EXPERIMENTAL PARASITOLOGY

The molecular and histopathological investigations of TLR2 rs5743708 and TLR4 (rs4986790 and rs4986791) polymorphisms effects on cutaneous leishmaniasis lesions
Feiz-Haddad MH, Moradkhani MA, Sefat F and Ali SA
Cutaneous leishmaniasis (CL), a zoonotic and neglected disease, is prevalent in numerous regions, particularly in tropical and sub-tropical countries. In Iran, endemic foci of leishmaniasis exist in specific regions, with zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania major being common in most rural areas. Toll-like receptors (TLRs) play a crucial role in both innate and adaptive immunities, and the investigation of TLR2 rs5743708 and TLR4 (rs4986790 and rs4986791) polymorphisms in parasitic diseases can have significant implications for patient treatment. In the present study, a total of 88 leishmaniasis patients using the patients' lesions from Khuzestan province health-treatment centers, Iran, including 50 cases (56.8%; Central region) and 38 cases (43.2%; Western region) underwent examination between the years 2022 and 2023. Two direct smears from the lesions of each patient were prepared and one of the smears was stained with Giemsa for parasitological examination. Among the 88 patients, the highest frequency was observed in the 21-30 years' age group (35.2%), while the lowest was in the 11-20 years' age group (10.2%). No statistically significant relationship was found between gender and age (P > 0.05). Following disease confirmation via microscopic examination, TLR2 rs5743708 and TLR4 (rs4986790 and rs4986791) polymorphisms in the patients were assessed using PCR-RFLP. Fragments of 264, 249, and 406 base pairs were successfully amplified, targeting the TLR2 and TLR4 genes, respectively. Out of the 88 leishmaniasis patients, 14 cases (15.9%) exhibited polymorphisms. Notably, all individuals in the polymorphism group carried both the TLR2 rs5743708 homozygous and the TLR4 rs4986791 heterozygous genotype combinations. There were no observations of TLR2 rs5743708 heterozygous, TLR4 rs4986790 heterozygous and homozygous and TLR4 rs4986791 homozygous genotypes within the polymorphism group. Biopsies from lesions for all contributors were prepared for histopathological examination. All patients with polymorphism showed larger lesions than patients without polymorphism (P < 0.05). Histophatological study showed abnormal cases in patients with polymorphism including mild hyperkeratosis, mild acanthosis, focal parakeratosis in the epithelium surface and mild hyperpigmentation of melanocytes in the basal layer. Furthermore, a strong infiltration of immune cells such as PMNs and a small number of lymphocytes was observed in the epidermal region of patients with polymorphisms. There was no statistically significant relationship between age and the quantity of lesions (P > 0.05). Additionally, some regions of the epidermal surface layer displayed pustule formation in patients with polymorphisms. No significant difference was discerned in the dermal layers of patients with polymorphisms compared to other patients. Considering that all patients with polymorphisms concurrently had TLR2 rs5743708 homozygous and TLR4 rs4986791 heterozygous genotype combinations, the anomalies observed in conjunction with histological changes in the skin lesions of patients with CL may plausibly be linked to the polymorphisms. Nonetheless, a more expansive dataset involving a larger population is imperative to comprehensively elucidate the pathogenesis of the Leishmania parasite and the potential impact of TLR2 rs5743708 and TLR4 (rs4986790 and rs4986791) gene polymorphisms in individuals afflicted with CL across diverse geographical locales.
Saikosaponin inhibits Eimeria tenella infection by modifying the NF-κB pathway and regulating cytokines and the intestinal microbial community
Meng X, Gan X, Wang Y, Zhang Q, Duan X, Wang Y, Zhao Q and Cai Y
Eimeria tenella (E. tenella) is an intestinal parasite that not only endangers the health of broiler chickens but may also cause death in severe cases. However, the growing critical problem of drug resistance in E. tenella complicates therapy. Consequently, a more natural and safer technique for treating E. tenella is urgently warranted. Saikosaponin (SS) is a saponin component extracted from the traditional Chinese herb Chaihu that has been demonstrated to treat various diseases. However, little is known regarding the function of SS in E. tenella treatment. In the present investigation, SS lowered the weight loss rate and increased the survival rate of broiler chickens infected with E. tenella. SS inhibited the NF-κB pathway and regulated the gut microbiota structure to inhibit E. tenella-induced inflammatory damage in broiler chickens. In addition, 16S high-throughput sequencing results demonstrated that SS reconstructed the gut microbiota of E. tenella infected broilers, preserving gut microbial balance, increasing the production of total short-chain fatty acids (SCFAs), repairing intestinal villi and intestinal wall integrity, and decreasing inflammatory cell infiltration in the cecum. Overall, these findings show that SS could prevent E. tenella-induced inflammatory damage in broiler chickens by blocking the NF-κ B pathway and regulating the gut microbiota composition.
Investigating the therapeutic effects of curcumin nanocapsules in hydatid cyst-infected mice
Sorouri N, Soleymani N, Sadr S, Rahdar A, Ebrahimzadeh E and Borji H
The primary treatment for cysts is surgery, including removing the cyst and administering the appropriate chemical drugs. Herbal remedies have gained popularity as a viable and secure alternative to conventional pharmaceuticals. It may be advantageous to use nanocapsules to overcome the bioavailability challenges associated with herbal remedies like curcumin. The present study aims to provide insights into the effectiveness of curcumin nanocapsules in treating hydatid infections.
A rapid and simple micro-assay to assess catalase activity in individual mosquito tissues
Ward MCE and Fallon AM
Oxidative stress generated as a normal byproduct of aerobic metabolism is minimized by the enzyme catalase (CAT; EC 1.11.1.6), which reduces hydrogen peroxide to molecular oxygen and water. In various mosquitoes, hydrogen peroxide and/or CAT activity have been implicated in oxidative responses to viral and protozoal pathogens as well as in ovarian maturation and insecticide resistance. We combined features of various CAT assays to develop a simple micro-assay that enables comparison of enzyme activities in individual mosquito tissues on a microscope slide. Activity recovered in the supernatant of mosquito whole body homogenates was inhibited by the CAT-specific inhibitor 3-amino-1,2,4-triazole. Activity was higher in blood-fed mosquitoes, consistent with exogenous enzyme in vertebrate blood. Triton X-100 improved evaluation of dissected organs, and accurate comparisons required careful removal of extraneous tissues. In unfed mosquitoes baseline CAT activity was lower in ovaries than in midgut or fatbody, but increased as oocytes matured after a blood meal, and was detectable in a single mature egg. CAT has unusual kinetics and can be difficult to assay directly. Our observations provide a simple approach for direct evaluation of CAT activity independent of changes in transcript levels and results of RNAi-based interference.
The role of NF-κB transcription factor in the regulation of cytokine induced thermal hyperalgesia in a Leishmania major model in BALB/c mice
Hoblos R, Khalil K, Karam M and Bazzi S
Cutaneous leishmaniasis caused mainly by Leishmania major (L. major) is one of the trending models used to investigate induced hyperalgesia and the involved cytokines. Previous studies approached the role of several cytokines in the observed hyperalgesia, but the molecular mechanisms orchestrating such a response still needed to be addressed. In this study, we inspect the role of the NF-κB in the modulation of L. major-prompted hyperalgesia and cytokine expression in BALB/c mice by administering celastrol, a potent blocker of this transcription factor. Intraperitoneal injection of 0.5 mg/kg and 1 mg/kg of celastrol attenuated the L. major-induced thermal hyperalgesia in BALB/c mice for 15 days and 21 days, respectively, as detected by hot plate and tail flick behavioral assessments. Cytokine levels were quantified in the infected paws of BALB/c mice using Sandwich ELISA. The administration of 1 mg/kg celastrol decreased TNF-α levels in L. major infected mice for 23 days, and IL-1β expression declined significantly for 23 days using both celastrol dosages. However, no significant change was observed in the levels of IL-10 in our experimental groups. The activation of NF-κB was detected by observing the phosphorylation levels of the p65 subunit using PathScan phospho-ELISA. The level of NF-κB phosphorylation was elevated in L. major infected BALB/c mice. Only administering 1 mg/kg celastrol suppressed the phosphorylation of p65, thus inactivating NF-kB. In conclusion, our results provide new insights into the correlation between the activation of NF-kB, the induction of thermal hyperalgesia, and the expression of TNF-α and IL-1β in the L. major-induced hyperalgesia model.
Expression pattern of ARG1 and iNOS genes in macrophages of Rhombomys opimus, BALB/c and C57BL/6 mice exposed to Leishmania major and salivary gland homogenates of Phlebotomus papatasi
Shirazian M, Taghipour N, Akhavan AA, Tabaei SJS, Abaei MR, Firouzjaie F, Fatemi M, Mosaffa N and Moin Vaziri V
Early interactions between Leishmania-macrophages (MQ) of host and effect of sand fly saliva are central to leishmaniasis outcome. Macrophages are able to kill or act as long-term hosts of parasite depending on host immunity. It proved that immunogenic proteins in sand fly saliva mostly have an exacerbating effect on leishmaniasis by up-regulating cytokines. We have explored expression of Arginase 1 (ARG1) and inducible Nitric Oxide Synthase (iNOS) genes in macrophages of three different rodents, BALB/c (susceptible), C57BL/6 (resistant) and Rhombomys opimus (R. opimus, natural reservoir) in presence of Leishmania major (L. major), salivary gland homogenate (SGH) of Phlebotomus papatasi (Ph. papatasi) and finally L. major + SGH. Stationary phase of promastigotes was used; salivary glands were extracted from female of Ph. papatasi (3-5 day-old/non-blood fed). SGH prepared by sonication. Macrophages harvested from the peritoneal cavity of each rodent and grouped as follow; 1) macrophage (control group), 2) MQ + L.major 3) MQ + SGH 4) MQ + L.major + SGH. After 6 h of incubation, culture medium supernatant collected, RNA extraction and cDNA synthesis performed, expression level of desired genes checked by Real-time PCR. ARG1 expression pattern in MQ + SGH and MQ + L.major group showed the highest and lowest expressions level respectively in BALB/c and C57BL/6. But, in MQ + L.major + SGH, although the highest ARG1 expression happened in BALB/c again, the lowest one observed in R. opimus. On the other hand, iNOS expression showed significant increase in all treated group of C57BL/6 macrophages. Interestingly, iNOS expression showed significant differences in MQ + L.major group of C57BL/6 in comparison to other rodents. Expression of ARG1 and iNOS in macrophages of BALB/c and C57BL/6 and R. opimus are different and can justify their clinical outcome of disease. The difference in gene expression pattern is related to the genetics of host and shows that genetic differences between hosts can affect the immune responses caused by saliva proteins even of the same species of sand fly.
Preparation, characterization, and in vivo activity of Gossypium hirsutum niosomes against cutaneous leishmaniasis caused by Leishmania major in a murine model: Parasite burden, gene expression, and histopathological profiling
Sharifi I, Salarkia E, Dabiri S, Pardakhty A, Sharifi F and Mohamadi N
The use of conventional drugs is not a satisfactory treatment for the disease. Therefore, there is a crucial need for alternative therapeutic approaches. This study aimed to investigate the potential anti-leishmanial activity of Gossypium hirsutum niosomes against cutaneous leishmaniasis in a murine model and evaluate their effectiveness by assessing parasite burden, immunomodulatory gene expression, and histopathological profile. We prepared G. hirsutum niosomes and characterized their morphology, size, Fourier transform infrared spectroscopy (FT-IR), and encapsulation efficiency. The in vivo anti-leishmanial activity of the niosomes was evaluated by assessing parasite burden, histopathological profile, and gene expression level. The spleen parasite load in BALB/c mice treated with different groups of G. hirsutum niosomes and G. hirsutum extracts (30%), demonstrated a significant decrease compared to Glucantime®. The least number of leishmanial parasites was observed in H and E-stained histological sections (grade+1), followed by G. hirsutum niosomes or G. hirsutum crude extract (grade+3), Glucantime® (grade+4) and the highest number in the untreated control group (grade+6). There was a substantial difference (P<0.001) among various treatment groups. Moreover, G. hirsutum niosomes up-regulated the levels of the gene (particularly IFN-γ, P < 0.001) compared to the extract form and Glucantime®. In contrast, IL-4, IL-10, and TNF-β were significantly decreased (P < 0.001) in comparison to untreated control. These results suggest that G. hirsutum niosomes have the potential to be considered a promising alternative therapy for leishmaniasis. Further research is warranted to explore their mechanism of action and optimize their formulation for clinical use.
Corrigendum to "Plasmodium yoelii: Contribution of oocysts melanization to natural refractoriness in Anopheles dirus" [Exp. Parasitol. 116 (2007) 433-439]
Wen-Yue X, Jian Z, Tao-Li Z, Fu-Sheng H, Jian-Hua D, Ying W, Zhong-Wen Q and Li-Sha X
ئAntiparasitic activity of Cerastes cerastes venom on Schistosoma mansoni infected mice‏
Mahdy A, Mostafa OMS, Aboueldahab MM and Nigm AH
This study investigates whether Cerastes cerastes venom (CCV) administrated at different doses (3 and 6μg/mouse) and times (a week pre-infection, the first week post-infection, and the fifth week post-infection) possesses antischistosomal activity on Schistosoma mansoni infected mice. The results showed that treatment with half lethal dose (6 μg/mouse) of CCV, at various time schedules, led to a significant decrease in the total worm burden. However, quarter lethal dose (3μg/mouse) of CCV showed a significant decrease in the total worm burden only when administered a week pre-infection. The total number of deposited eggs by females of S. mansoni was significantly decreased in the liver and the intestine of mice treated with 3μg/mouse or 6μg/mouse CCV, associated with significant alterations in the oogram pattern with significant elevation in dead eggs levels and significant decrease in the number of mature eggs. Histological examinations illustrated a significant decrease in the number and diameter of hepatic granulomas in high dose (6μg/mouse) CCV-treated groups, while it was significant only a week pre-infection in low dose (3μg/mouse) CCV-treated groups. CCV also caused several tegumental changes in treated female and male worms, including loss of the normal surface architecture, tubercular destruction, loss of tubercles' spines, oedema, erosion, membrane blebbing, and swelling. S. mansoni-infected mice groups treated with CCV (6μg/mouse) a week before infection and at fifth week post-infection had, in all individuals up to a dilution of 1:1600, higher levels of antibodies against adult worm antigen. The current investigation found that C. cerastes venom has potential antischistosomal action in a time and dose-dependent manner (more enhanced antischistosomal effects at a dose of 6 μg and in the group treated in a week before infection), in addition to its potential immunomodulatory effect against schistosomiasis infection. More studies will be required to identify the venom's active ingredients that affect the host's immunology. This information could be used in the future to develop novel antischistosomal therapies.
Antitrypanosomal and antileishmanial activity of compounds from some Nigerian plants
Alenezi S, Igoli NP, Gray AI, Oaikhena EE, Alfayez IA, de Koning HP and Igoli JO
Ten compounds, six extracts and five fractions obtained from three Nigerian plants were assayed for their in vitro antitrypanosomal and antileishmanial activities. Each plant was extacted with hexane, ethyl acetate, and methanol. Isolated compounds were characterized and identified based on their NMR chemical shifts and comparison to literature reports. The crude extracts, fractions and isolated compounds were tested against the kinetoplastid parasites: bloodstream forms of Trypanosoma brucei Lister 427WT and the derived multi-drug resistant clone B48, and promastigote forms of Leishmania mexicana cas9/T7 and the derived clone cas9ΔNT1. Column chromatography of the extracts using silica gel yielded ten compounds identified as curzerenone, epi-curzerenone, chloranthene F, isofuranodienone, 8(17)-12E-labdadiene-15, 16-dial and 15-hydroxy-8(17),12E-labdadiene-16-al from Siphonochilus aetiopicus, lupeol, linalolic acid and spinasterone from Calliandra portoricensis, and abruquinone B from Abrus precatorius. The assay results showed that the Siphonochilus aetiopicus and Calliandra portoricensis crude extracts, fractions and compounds displayed moderate activity against the Trypanosoma brucei but showed less activity against Leishmania mexicana. Abrus precatorius crude extract, fraction, and isolated compound exhibited only weak trypanocidal and leishmanicidal activities against both kinetoplastid parasites tested. These findings have provided evidence for the use of Siphonochilus aetiopicus and Calliandra portoricensis in traditional medicine relating to parasitic diseases.
Therapeutic efficacy of praziquantel loaded-chitosan nanoparticles on juvenile Schistosoma mansoni worms in murine model
Mahmoud M, Allam AF, Essawy AE, Shalaby TI and El-Sherif SS
Praziquantel (PZQ) is the standard treatment for schistosomiasis; however, it is poorly effective on immature and juvenile worms. The present study aimed to evaluate the therapeutic efficacy of praziquantel loaded-chitosan nanoparticles (PZQ-CSNPs) on the 25 days old juvenile Schistosoma mansoni worms compared to PZQ and chitosan nanoparticles (CSNPs). It was conducted on 60 Swiss albino mice, including 20 control and 40 experimental mice. The control groups included healthy uninfected and infected non-treated mice. The experimental groups included mice infected treated on the 25th day with 400 mg/kg PZQ, 30 mg/kg CSNPs, 100 mg/kg, and 400 mg/kg PZQ-CSNPs. The results revealed that PZQ-CSNPs (100, 400 mg/kg) gave the best results substantiated by a remarkable decrease in worm burden, egg count, granuloma count and size compared to the other treatments. Moreover, it induced severe deformations of worm morphology regarding oral and ventral suckers, tegument, spines distribution, and male gynaecophoric canal. Liver enzymes and oxidative stress markers were significantly decreased while antioxidant activities were increased compared to control and other treated groups. In conclusion, a single dose of PZQ-CSNPs had significant antischistosomal therapeutic effects during the early maturation phase.
Effects of environmental factors on host-parasite interaction patterns in backyard-tethered goats of Kerala, India
Ajith Y, Adithya S, Athira KS, Beena V, Safeer MS, Mevin SM, Preena P, Nisha AR, Manju M, Arun G and Ajithkumar S
The environment is the most important stratum in the epidemiological triad of a parasitic disease and any variations in the environmental factors may decide the dynamic occurrence and existence of different lifecycle stages of these parasites. The present study investigated the correlations between key biometeorological and demographical parameters with the incidence of different gastrointestinal parasites and hemoparasites among goats. Four hundred and thirty-two goats were screened for parasitic infection in a yearlong survey conducted from July 2022 to June 2023 in the Teaching Veterinary Clinical Complex, Mannuthy, Kerala, India. The weather parameters (T, T, RH, THI, and bright sunshine hours), air quality parameters [AQI, PM, and PM], and demographic parameters (gender and age) were recorded along with the test positivity of different categories of gastrointestinal parasites and hemoparasites in goats by routine fecal sample examination and blood smear examination, respectively. The infection level was ranked based on the severity of the infection. The mean and daily variations in biometeorological parameters were calculated and the data were statistically analyzed to figure out the pertinent correlations in host-parasite-environment interaction patterns. High levels of parasitic infections with significant month-wise variations and climate-correlated peak infection patterns were noticed. The incidence of parasites was negatively correlated to all parameters except humidity, indicating more severe parasitism during monsoon months. The significant variations in the host-parasite interaction dynamics point towards the need for detailed explorations concerning the lifecycle of each specific parasite with a focus on the possible environment-favourable and resistant lifecycle stages. Future studies may be designed from a biometeorological perspective to develop a crucial understanding of host-parasite-environment interactions in goats ensuring sustainable goat farming.
Corrigendum to "Development and evaluation of a real-time PCR for genotyping of Cryptosporidium spp. from water monitoring slides" [Experiment. Parasitol. 242 (2022) 108366]
K E, G R, Perez-Cordon G and Rm C
In vivo Study of Nano Chitosan Beads-Based ELISA versus Traditional Sandwich ELISA for the Early Diagnosis of Trichinosis
Mahgoub AMA, Ali MI, Abu-Sarea EY, Rady SA, Bayoumi Ali IR and Sayed DR
Human trichinosis is a serious foodborne parasitic zoonosis. Diagnosing human trichinosis is usually difficult due to the nonspecific clinical picture and the limited effectiveness of serological tests in acute infections. While ELISA can detect circulating Trichinella antigens, aiding in early diagnosis, its sensitivity may be low. The application of nanoparticles can improve the sensitivity of ELISA and allow a specific early diagnosis of the disease. This work compares the nano chitosan beads-based ELISA (NCSB-ELISA) and traditional sandwich ELISA for the detection of circulating Trichinella spiralis (T. spiralis) crude extract-antigen (CEA) in serum samples of experimentally infected mice. Fifty-seven mice included in this study were classified into 3 groups: T. spiralis infected group (Group I) (36 mice), which was equally subdivided into six subgroups according to the time of sacrifice (6, 8, 10, 12, 14 and 16) day post-infection (dpi), cross-reactivity group (Group II) (9 mice) and negative control group (Group III) (12 mice). T. spiralis AW-CEA prepared from the adult worms were used to produce anti- T. spiralis IgG-polyclonal antibodies in rabbits; these antibodies were utilized to detect AW-CEA in serum samples by traditional sandwich ELISA and NCSB-ELISA. Using NCSB-ELISA, T. spiralis AW-CEA was detected in sera collected at 8 dpi, with a sensitivity of 50% and a specificity of 100%. Meanwhile, traditional sandwich ELISA could not detect the antigen at the same time interval. Both ELISA techniques were able to detect the antigen in samples collected at 10, 12, 14 and 16 dpi with a sensitivity of 16.67%, 50%, 67.67% and 83.67%, respectively, for traditional sandwich-ELISA and a specificity of 100% at 10, 12 and 14 dpi while at 16 dpi specificity was decreased to 90.91%. In contrast, the sensitivity of NCSB-sandwich ELISA on the same days was 66.67%, 83.34%, 100% and 100%, respectively, with a specificity of 100% at all days. False positive detection of T. spiralis AW-CEA in the serum of mice in GII was recorded on day 16 pi by only traditional sandwich ELISA. This study concluded that NCSB-ELISA is a promising and sensitive technique for the early and specific diagnosis of acute trichinosis in an animal model.
RAD51 recombinase and its paralogs: Orchestrating homologous recombination and unforeseen functions in protozoan parasites
Flores-Vega JJ, Puente-Rivera J, Sosa-Mondragón SI, Camacho-Nuez M and Alvarez-Sánchez ME
The DNA of protozoan parasites is highly susceptible to damage, either induced by environmental agents or spontaneously generated during cellular metabolism through reactive oxygen species (ROS). Certain phases of the cell cycle, such as meiotic recombination, and external factors like ionizing radiation (IR), ultraviolet light (UV), or chemical genotoxic agents further increase this susceptibility. Among the various types of DNA damage, double-stranded breaks (DSBs) are the most critical, as they are challenging to repair and can result in genetic instability or cell death. DSBs caused by environmental stressors are primarily repaired via one of two major pathways: non-homologous end joining (NHEJ) or homologous recombination (HR). In multicellular eukaryotes, NHEJ predominates, but in unicellular eukaryotes such as protozoan parasites, HR seems to be the principal mechanism for DSB repair. The HR pathway is orchestrated by proteins from the RAD52 epistasis group, including RAD51, RAD52, RAD54, RAD55, and the MRN complex. This review focuses on elucidating the diverse roles and significance of RAD51 recombinase and its paralogs in protozoan parasites, such as Acanthamoeba castellanii, Entamoeba histolytica (Amoebozoa), apicomplexan parasites (Chromalveolata), Naegleria fowleri, Giardia spp., Trichomonas vaginalis, and trypanosomatids (Excavata), where they primarily function in HR. Additionally, we analyze the diversity of proteins involved in HR, both upstream and downstream of RAD51, and discuss the implications of these processes in parasitic protozoa.
Silver nanoparticles exhibit in vitro anthelmintic and antimicrobial activities against Dactylogyrus minutus (Kulwieć, 1927), and Aeromonas hydrophila in Cyprinus carpio Koi
Gomes Dos Santos G, Perenguez Riofrio LV, Miguel Libanori MC, Capistrano Dos Santos P, Costa DS, Pereira Junior JA, Vaz da Silva A, Lopes EM, de Souza AP, Pedreira Mouriño JL, Nogueira DJ, Jerônimo GT and Martins ML
The study aimed to evaluate the in vitro anthelminthic and antimicrobial activity of silver nanoparticles (AgNPs) against Dactylogyrus minutus and Aeromonas hydrophila, pathogens of Cyprinus carpio Koi. Gill arches of the fish were removed and placed into six-well plates containing 10 mL of tank water with varying concentrations of AgNPs: 100, 400, 500, 600, and 800 mg/L, along with control groups using tank water and distilled water. Each group was tested in triplicate. Parasites were observed every 10 min for 300 min (5 h) using a stereomicroscope, and mortality rates were recorded. Anthelminthic efficacy was calculated at the end of the tests. For the in vitro antimicrobial test, the Minimum Inhibitory Concentration (MIC) of AgNPs was determined by adding 100 μL of Poor Broth (PB) culture medium to all 96 wells of a microplate. The first well was filled with 100 μL of AgNPs, followed by serial dilutions (1:2 ratio). Subsequently, 50 μL of A. hydrophila (1 × 10 CFU/mL) was added to all wells and incubated for 24 h at 28 °C. Results showed that 800 mg/L of AgNPs achieved 87% anthelminthic efficacy within 300 min, while 100 mg/L achieved 47% efficacy. The MIC showed bacterial growth inhibition at 125 mg/mL. Despite the 87% efficacy against parasites within 300 min, AgNPs did not reach 100% efficacy quickly, limiting their potential use in ornamental fish farming. Further studies are needed to assess the toxicity of AgNPs in fish.
Preliminary evaluation of the protective effect of rEi-SAG19 on Eimeria intestinalis infection in rabbits
Pu J, Hao G, Chen H, He W, Xiong C, Xiao J and Yang G
Eimeria intestinalis is one of the most pathogenic coccidia species in rabbits. Anticoccidial treaments are the main measures to control rabbit coccidiosis now, but there are drug resistance and residues concerns. Therefore, vaccine has been used as an alternative strategy. The surface antigens (SAGs) of apicomplexan protozoa play a role in adhesion and invasion of host intestinal cells, and are considered to be potential candidate antigens for vaccines. In this study, transcriptional analysis of 5 Ei-SAGs genes at four developmental stages was conducted, then the Ei-SAG19 gene were screened out for prokaryotic expression and the reactogenicity of recombinant SAG19 (rEi-SAG19) was investigated by immunoblotting. To assessment the protective effects of rEi-SAG19, rabbits (n = 40) were randomly divided into four groups (Blank control, PBS-infected, Trx-His-S-Quil-A-infected and rEi-SAG19 immunized groups), the rEi-SAG19 immunized group was subcutaneously immunized with 100 μg rEi-SAG19 in the neck with an interval of two weeks, and challenged with 5 × 10 homologous oocysts two weeks after the second immunization. Two weeks after the challenge, all rabbits were sacrificed. After that, the level of serum specific IgG antibody was detected weekly and the level of cytokines in serum before the challenge were determined. At the end of the experiment, the weight gain, oocyst reduction rate, lesion score and anticoccidial index (ACI) were calculated. The results showed that rEi-SAG19 has a good reactogenicity. The relative weight gain rate, oocyst reduction rate and ACI of the rabbits in rEi-SAG19 immunized group were 80.51%, 72.6%, and 165.1, respectively, which has a moderate protective effect. The level of serum specific IgG antibody and IL-4 rised significantly (P < 0.05), but the levels of IL-2, IFN-γ and IL-10 had no significant difference (P > 0.05). Our results indicated that rEi-SAG19 could provides moderate protective effect against E. intestinalis infection in rabbits (ACI = 165.1). Therefore, rEi-SAG19 could be used as a vaccine candidate antigen for E. intestinalis.
Trypanosoma cruzi P21 protein exacerbates Leishmania (L.) amazonensis infection
Teixeira TL, Teixeira SC, Borges BC, Servato JPS, Oliveira ECM, Velikkakam T and Silva CVD
The protozoan parasite Trypanosoma cruzi, the etiological agent of Chagas disease, affects millions of people worldwide. Current treatments rely on drugs effective only in the acute phase, making the search for new therapeutic targets a priority. While a recombinant protein based on T. cruzi P21 (rP21) exhibits immunomodulatory properties and contributes to controlling parasitism and inflammation during T. cruzi infection, its efficacy against other trypanosomatids remains unexplored. This study investigated the impact of rP21 on Leishmania (L.) amazonensis infection in a murine model. Contrary to our expectations, treatment with rP21 did not ameliorate L. (L.) amazonensis infection. Instead, rP21 treatment resulted in increased parasite load in the paws of infected BALB/c mice, evidenced by larger lesion sizes and higher parasite burdens, accompanied by an intensified inflammatory infiltrate in the paw tissue. These findings suggest that despite its promising effects in the context of T. cruzi infection, rP21 may not be a suitable therapeutic candidate for L. amazonensis infection and might even exacerbate disease.
Structural elucidation of andrographolide from Andrographis paniculata and its ovicidal, larvicidal and pupicidal activities against Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae)
Vilvest J, Milton MCJ, Yagoo A and Balakrishna K
Both human beings and animals around the globe are vulnerable to the transmission of infectious diseases carried by mosquitoes. They have the ability to transmit a diverse array of pathogenic agents, such as viruses and parasites, while feeding on blood. The objective of this research is to investigate andrographolide isolation, characterization, and structure elucidation from Andrographis paniculata. Furthermore, it aims to evaluate the activity of andrographolide against the immature stages of Aedes aegypti and Culex quinquefasciatus. The fractions obtained from A. paniculata extracts underwent further purification and analysis to identify the most active ones. To confirm the structure of andrographolide, spectroscopic methods including IR, H-NMR, C-NMR, and GC-MS were used. Biological assays were conducted to assess its ovicidal, larvicidal, and pupicidal activities. Importantly, andrographolide demonstrated moderate ovicidal activity, resulting in mortality rates of 36% and 32% in Ae. aegypti and Cx. quinquefasciatus eggs, respectively, at a concentration of 2 ppm. Additionally, it exhibited strong larvicidal and pupicidal efficacy, with LC values of 2.02 ppm and 3.19 ppm against Ae. aegypti larvae and pupae, and 2.14 ppm and 2.73 ppm against Cx. quinquefasciatus larvae and pupae. These findings highlight the potential of andrographolide as a powerful natural compound in mosquito control efforts. Furthermore, this study underscores the importance of natural products as viable alternatives to synthetic insecticides in managing vector-borne diseases.
Characterization and phylogenetic analysis of the complete mitochondrial genome of Rhabdias kafunata (Rhabditida: Rhabdiasidae)
Li YX, Huang XH, Li MR, Li SY, Huang ZJ, Wang DF, Yin GW and Wang L
Rhabdias kafunata (Rhabditida: Rhabdiasidae) is a parasitic nematode that significantly affects bufonids. To better understand the genome-level characteristics of related species, Illumina sequencing was used to identify mitochondrial genes and analyze their basic characteristics and gene arrangements. The mitogenome of R. kafunata is 14,068 bp in length and contains 36 genes, including 12 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes and one noncoding region (NCR). The nucleotide composition is highly biased toward A + T, accounting for 75.5% of the entire mitochondrial genome. The cox1 sequence is relatively conserved in Ka/Ks analyses and can be used as a gene fragment for species identification. While 8 of the 12 PCGs use the typical ATN initiation codon, nad1-2, nad4, and cox3 utilize a TTG initiation codon. Most stop codons end with the standard TAA or TAG, except for cytb, which ends with an incomplete TA. Additionally, trnM, trnK, and trnI have the typical clover-leaf secondary structure, while the remaining tRNAs lack the DHU arm or TΨC arm. Phylogenetic analysis indicates that R. kafunata belongs to the Rhabditidae family and is closely related to Litoditis marina and Caenorhabditis angaria among sequenced lepidopteran mitochondrial genomes.
Applicability of three indices to evaluate the reproductive capacity of Rhipicephalus microplus engorged female ticks in acaricide efficacy trials
Sarli M, Morel N and Nava S
This study aimed to analyze the applicability of three different indices to evaluate the reproductive capacity of engorged females (RCEF). The indices, RCEF, RCEF and RCEF, were proposed as alternative to the count of the exact number of unhatched eggs and larvae in in vivo and in vitro acaricide efficacy trials that involve the use of engorged females to estimate the effect of a drug on their reproductive capacity. A comparison of the values of the reproductive efficiency index (REI) and the fertility efficiency index (FEI) of ten engorged females calculated from the count of the exact number of unhatched eggs and larvae and from the application of the proposed indices was performed. The absence of differences in the values obtained by both methods support the reliability and validate the use of the RCEF, RCEF and RCEF indices to assess the RCEF.