Efficacy of biorational insecticides against Bemisia tabaci (Genn.) and their selectivity for its parasitoid Encarsia formosa Gahan on Bt cotton.

The toxicity of seven biorational insecticides [five insect growth regulators (Buprofezin, Fenoxycarb, Pyriproxyfen, Methoxyfenozide, and Tebufenozide) and two oil-extracts of neem and bitter gourd seeds] against Bemisia tabaci and their selectivity for its parasitoid, Encarsia formosa were evaluated in laboratory and field conditions for 2 years (2018-2019) in Pakistan. Toxicity results demonstrate that Pyriproxyfen, Buprofezin, and Fenoxycarb proved to be effective (80-91% mortality and 66.3-84.2% population-reduction) against B. tabaci followed by Methoxyfenozide, Tebufenozide (50-75% mortality and 47.8-52.4% population-reduction), and then oil-extracts of neem and bitter gourd (25-50% mortality and 36.5-39.8% population-reduction) in the laboratory [72 h post-application exposure interval (PAEI)] and field trails (168 h PAEI), respectively. All tested biorationals, except Methoxyfenozide [(slightly-harmful/Class-II), i.e., causing mortality of parasitoids between a range of 25-50%] and Tebufenozide [(moderately-harmful/Class-III), i.e., causing mortality of parasitoids between the ranges of 51-75%], proved harmless/Class-I biorationals at PAEI of 7-days in the field (parasitism-reduction < 25%) and 3-days in the lab (effect < 30%). In laboratory bioassays, exposure of parasitized-pseudopupae and adult-parasitoids to neem and bitter gourd oils demonstrated that these compounds proved harmless/Class-I biorationals (< 30% mortality). Alternatively, Pyriproxyfen, Buprofezin, Fenoxycarb, Methoxyfenozide, and Tebufenozide were slightly-harmful biorationals (30-79% mortality) against the respective stages of E. formosa. We conclude that most of the tested biorationals proved harmless or slightly harmful to E. formosa, except tebufenozide after PAEI of 7-days (168 h) in the field and, therefore, may be used strategically in Integrated Pest Management (IPM) of B. tabaci.

Copaifera spp. oleoresins impair Toxoplasma gondii infection in both human trophoblastic cells and human placental explants.

The combination of pyrimethamine and sulfadiazine is the standard care in cases of congenital toxoplasmosis. However, therapy with these drugs is associated with severe and sometimes life-threatening side effects. The investigation of phytotherapeutic alternatives to treat parasitic diseases without acute toxicity is essential for the advancement of current therapeutic practices. The present study investigates the antiparasitic effects of oleoresins from different species of Copaifera genus against T. gondii. Oleoresins from C. reticulata, C. duckei, C. paupera, and C. pubiflora were used to treat human trophoblastic cells (BeWo cells) and human villous explants infected with T. gondii. Our results demonstrated that oleoresins were able to reduce T. gondii intracellular proliferation, adhesion, and invasion. We observed an irreversible concentration-dependent antiparasitic action in infected BeWo cells, as well as parasite cell cycle arrest in the S/M phase. The oleoresins altered the host cell environment by modulation of ROS, IL-6, and MIF production in BeWo cells. Also, Copaifera oleoresins reduced parasite replication and TNF-α release in villous explants. Anti-T. gondii effects triggered by the oleoresins are associated with immunomodulation of the host cells, as well as, direct action on parasites.

Peppermint essential oil inhibits Drosophila suzukii emergence but reduces Pachycrepoideus vindemmiae parasitism rates.

Spotted Wing Drosophila (Drosophila suzukii; Matsumura) is an invasive fruit fly with the ability to oviposit in a broad range of agriculturally valuable fruits. Volatile organic compounds (VOCs) produced by botanical oils may reduce D. suzukii's attraction to hosts and decrease survival, but it is unknown whether their efficacy varies across D. suzukii life stages or affects the survival and success of higher trophic levels. Through a series of laboratory bioassays, we evaluated the effects of peppermint (Mentha arvensis L.) oil produced VOCs on D. suzukii survival and the survival of and parasitism rates by a pupal parasitoid wasp, Pachycrepoideus vindemmiae (Rondani). First, we determined whether fumigation with peppermint oil VOCs at the pupal stage reduced adult emergence, and whether this depended on environmental conditions (i.e. soil moisture). Second, we evaluated whether fumigation with peppermint oil VOCs reduced or enhanced parasitism by the pupal parasitoid and whether this depended on the timing of peppermint oil VOC exposure (i.e. before, during, or after parasitoid access). Fumigation with VOCs of 4.5 mg of peppermint oil reduced D. suzukii emergence under moist soil conditions but dry soil had a similar effect on reducing adult emergence as peppermint oil presence. Peppermint oil VOC fumigation was toxic to adult P. vindemmiae, but developing P. vindemmiae were unaffected by peppermint oil VOC fumigation. Using peppermint essential oil as a fumigant may reduce D. suzukii emergence from the pupal stage. However, this could negatively impact P. vindemmiae dependent on the timing of application.

Nicotinamide Inhibits Aphid Fecundity and Impacts Survival.

Nicotinamide (NAM) alters behavior in C. elegans and Drosophila, serving as an agonist of TRPV channels affecting sensory neurons and mimicking the mode of action of insecticides used to control phloem-feeding insects. The impact of NAM on green peach aphid (Myzus persicae) behaviors was assessed in artificial diet assays and foliar applications to Arabidopsis plants. Aphids feeding on artificial diets supplemented with NAM impaired stylet movement causing feeding interruptions and ultimately starvation and death. Aphid feeding behaviors were negatively impacted on NAM sprayed plants at concentrations as low as 2.5 mM leading to increased mortality. In choice assays with NAM sprayed leaves aphids showed clear preference for untreated control leaves. NAM is an intermediate in the NAD salvage pathway that should accumulate in nicotinamidase (nic) mutants. LC-MS analysis showed NAM accumulates 60-fold in nic-1-1 Arabidopsis mutants as compared with Col-0. Aphid reproductive potential was significantly decreased on nic-1-1 mutant plants, resulting in a smaller colony size and arrested population development. The results support the hypothesis that dietary NAM causes behavioral changes in aphids, including altered feeding, reduced reproduction, and increased mortality. NAM is thought to bind to TRPV channels causing overstimulation of sensory neurons in the aphid feeding apparatus.

Probiotics and yogurt modulate oxidative stress and fibrosis in livers of Schistosoma mansoni-infected mice.

BACKGROUND: Considerable morbidity, mortality, and economic loss result from schistosomiasis infection. Deposition of Schistosoma eggs in the hepatic portal vein is considered as the main causative agent for the development of liver fibrosis and subsequent liver cirrhosis. Probiotics are exogenous and beneficial microorganisms to living hosts against the harmful effect of many parasites. Strong evidence suggests the importance of probiotics in the control strategy of helminth. The ultimate goal of this study is to evaluate the protective effect of probiotics and yogurt on Schistosoma mansoni-induced oxidative stress and hepatic fibrosis in mice. METHODS: Mice were infected by tail immersion of schistosomal cercariae followed by an oral treatment with either probiotics or yogurt for one week before infection and immediately post-infection. Mice were scarified on day 56 following infection with S. mansoni and liver sample were obtained. RESULTS: We showed that oral administration of probiotics or yogurt revealed a significant reduction in worm number, egg load, and granuloma size in liver tissue, which is mainly assigned to the decreased expression level of matrix metalloproteinases 9 (MMP-9) in liver tissue. A significant reduction in the oxidative stress markers-induced by S. mansoni infection including lipid peroxidation and nitrite/nitrate was also detected. The level of some antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase) and reduced glutathione was greatly enhanced. Furthermore, treatment with probiotics or yogurt inhibited apoptosis in hepatic tissue, which is mainly assigned to the decreased expression level of caspases-3 in liver tissue. CONCLUSION: Our findings represent the promising anti-schistosomal activities of probiotics and yogurt.

Direct and Indirect Inhibition Effects of Resveratrol against Toxoplasma gondii Tachyzoites In Vitro.

Toxoplasma gondii is one of the most widespread obligatory parasitic protozoa and infects nearly all warm-blooded animals, leading to toxoplasmosis. The therapeutic drugs currently administered, like the combination of pyrimethamine and sulfadiazine, show high rates of toxic side effects, and drug resistance is encountered in some cases. Resveratrol is a natural plant extract with multiple functions, such as antibacterial, anticancer, and antiparasite activities. In this study, we evaluated the inhibitory effects of resveratrol on tachyzoites of the Toxoplasma gondii RH strain extracellularly and intracellularly. We demonstrate that resveratrol possesses direct antitoxoplasma activity by reducing the population of extracellularly grown tachyzoites, probably by disturbing the redox homeostasis of the parasites. Moreover, resveratrol was also able to release the burden of cellular stress, promote apoptosis, and maintain the autophagic status of macrophages, which turned out to be regulated by intracellular parasites, thereby functioning indirectly in eliminating T. gondii In conclusion, resveratrol has both direct and indirect antitoxoplasma effects against RH tachyzoites and may possess the potential to be further evaluated and employed for toxoplasmosis treatment.

Lethal and Sublethal Effects on Tamarixia triozae (Hymenoptera: Eulophidae), an Ectoparasitoid of Bactericera cockerelli (Hemiptera: Triozidae), of Three Insecticides Used on Solanaceous Crops.

Lethal and sublethal effects of refined soybean oil, imidacloprid, and abamectin on Tamarixia triozae (Burks; Hymenoptera: Eulophidae) were assessed after exposure of the eggs, larvae, and pupae of this parasitoid to three concentrations of these active substances: the LC50 for fourth-instar Bactericera cockerelli (Sulc.; Hemiptera: Triozidae) and 50% and 100% of the minimum field-registered concentration (MiFRC). Soybean oil caused 26-61% mortality in T. triozae eggs and 6-19% in larvae; mortality in both eggs and larvae was ≤19% for imidacloprid and 4-100% for abamectin. All three compounds caused <18% mortality of T. triozae pupae, with the exception of the abamectin 50% (47%) and 100% (72%) MiFRC. The mortality of larvae and pupae derived from treated eggs was ≤39% for all three insecticides, and that of pupae derived from treated larvae was ≤10%. In general, emergence of adults developed from treated eggs, larvae, and pupae was affected more by abamectin than by the other treatments. The proportion of females derived from all three development stages was not affected by treatment with the compounds, except when the parasitoid was treated as larvae with the soybean oil 100 and 50% MiFRC (66 and 68%, respectively) or when treated as pupae with the imidacloprid LC50 and 100% MiFRC (~60%). Female longevity was generally higher than that of males. The use of imidacloprid, soybean oil, and abamectin in combination with T. triozae for pest control may be effective when the parasitoid is in the pupal stage because this stage is less susceptible than other immature stages.

Review of Experimental Compounds Demonstrating Anti-Toxoplasma Activity.

Toxoplasma gondii is a ubiquitous apicomplexan parasite capable of infecting humans and other animals. Current treatment options for T. gondii infection are limited and most have drawbacks, including high toxicity and low tolerability. Additionally, no FDA-approved treatments are available for pregnant women, a high-risk population due to transplacental infection. Therefore, the development of novel treatment options is needed. To aid this effort, this review highlights experimental compounds that, at a minimum, demonstrate inhibition of in vitro growth of T. gondii When available, host cell toxicity and in vivo data are also discussed. The purpose of this review is to facilitate additional development of anti-Toxoplasma compounds and potentially to extend our knowledge of the parasite.

Testing Dose-Dependent Effects of the Nectar Alkaloid Anabasine on Trypanosome Parasite Loads in Adult Bumble Bees.

The impact of consuming biologically active compounds is often dose-dependent, where small quantities can be medicinal while larger doses are toxic. The consumption of plant secondary compounds can be toxic to herbivores in large doses, but can also improve survival in parasitized herbivores. In addition, recent studies have found that consuming nectar secondary compounds may decrease parasite loads in pollinators. However, the effect of compound dose on bee survival and parasite loads has not been assessed. To determine how secondary compound consumption affects survival and pathogen load in Bombus impatiens, we manipulated the presence of a common gut parasite, Crithidia bombi, and dietary concentration of anabasine, a nectar alkaloid produced by Nicotiana spp. using four concentrations naturally observed in floral nectar. We hypothesized that increased consumption of secondary compounds at concentrations found in nature would decrease survival of uninfected bees, but improve survival and ameliorate parasite loads in infected bees. We found medicinal effects of anabasine in infected bees; the high-anabasine diet decreased parasite loads and increased the probability of clearing the infection entirely. However, survival time was not affected by any level of anabasine concentration, or by interactive effects of anabasine concentration and infection. Crithidia infection reduced survival time by more than two days, but this effect was not significant. Our results support a medicinal role for anabasine at the highest concentration; moreover, we found no evidence for a survival-related cost of anabasine consumption across the concentration range found in nectar. Our results suggest that consuming anabasine at the higher levels of the natural range could reduce or clear pathogen loads without incurring costs for healthy bees.

Evaluation of leishmanicidal activity and cytotoxicity of Ricinus communis and Azadirachta indica extracts from western Kenya: in vitro and in vivo assays.

BACKGROUND: Despite advances to targeted leishmanicidal chemotherapy, defies around severe toxicity, recent emergence of resistant variants and absence of rational vaccine still persist. This necessitates search and/or progressive validation of accessible medicinal remedies including plant based. The study examined both in vivo and in vitro response of L. major infection to combined therapy of Ricinus communis and Azadirachta indica extracts in BALB/c mice as the mouse model. A comparative study design was applied. RESULTS: BALB/c mice, treated with combination therapy resulted in significantly (p < 0.05) larger reduction of lesion than those treated with monotherapies. The spleno-somatic index was found to be significantly low with combination therapy than monotherapies. Antiparasitic effect of A. indica and R. communis on amastigote with a 50 % inhibitory concentration (IC50) was of 11.5 and 16.5 µg mL(-1) respectively while combination therapy gave 9.0 µg ml(-1) compared to the standard drugs, Pentostam and amphotericin B which had an IC50 of 6.5 and 4.5 µg ml(-1) respectively. Optimal efficacy of A. indica and R. communis was 72 and 59.5 % respectively, combination therapy gave 88 %, while Pentostam and amphotericin B had 98 and 92 % respectively against amastigotes. Against promastigotes A. indica and R. Communis gave an IC50 of 10.1, 25.5 µg mL(-1) respectively, while combination, 12.2 µg mL(-1) against 4.1 and 5.0 µg ml(-1) for Pentostam and amphotericin B respectively. The optimal efficacy of the compounds against promastigotes was 78.0, 61.5 and 91.2 % (A. indica, R. communis and A. indica + R. communis respectively) against 96.5 and 98 % for Pentostam and amphotericin B respectively. The concentrations at optimal efficacy were significantly different (p < 0.05) among the test compounds. An evaluation of the IC50 values of the combination therapies clearly reveals synergistic effects. CONCLUSION: Combination therapy of A. indica and R. communis had best antileishmanial activity than the monotherapies. The active ingredients of both R. communis and A. indica need to be fractionated, and studied further for activity against Leishmania parasites.

Effects of alcoholic extract of Curcuma longa on Ascaridia infestation affecting chicken.

Ascaridia galli, the common intestinal nematode, remains a major cause of economic loss in the poultry industry in developing countries. Treatments using chemicals are not only expensive but also affect host health. Plant extracts as better alternative is gaining significance. Here, we have studied the effects of alcoholic extract of turmeric, Curcuma longa L. (Zingiberaceae) roots, against A. galli infection in chicken. Different concentrations of C. longa root extract were tested in vitro on 5 groups of adults A. galli worms and in vivo on 6 groups of chicks. The results showed that the turmeric root extract @ 60 mg mL(-1) in vitro significantly (P < 0.001) proved paralytic and fatal against worms (16.80 ± 1.28 h). In vivo, chicken groups (G2-G6) were infected with an average of 300 ± 12 embryonated eggs of A. galli. The G2 was not given any treatment while G3 was treated with piperazine (@ 200 mg kg(-1) body wt.); and Groups 4, 5 and 6 were given turmeric @ 200, 400 and 600 mg kg(-1) body wt., respectively. The mean number of worms extracted at the end of the trial in G2 (untreated) was 18.10 ± 2.42, while the G3 treated with piperazine had no worms. Groups 4 and 5 did not show any significant difference compared to G2. However, G6 that had 3.20 ± 1.33 worms was statistically significant. Higher concentrations of turmeric given to infected chickens significantly reduced the length and weight of worms. The study showed that the worm infestation damaged the intestinal villi, and.treatment with high concentration of C. longa had healing effects and restored the integrity of intestinal mucosa. The results have demonstrated the ameliorating effect of C. longa turmeric on A. galli infested chickens.

Effects of tannin-rich host plants on the infection and establishment of the entomopathogenic nematode Heterorhabditis bacteriophora.

Parasitized animals can self-medicate. As ingested plant phenolics, mainly tannins, reduce strongyle nematode infections in mammalian herbivores. We investigated the effect of plant extracts known to be anthelmintic in vertebrate herbivores on the recovery of the parasitic entomopathogenic nematode Heterorhabditis bacteriophora infecting African cotton leafworm (Spodoptera littoralis). Nematode infective juveniles (IJs) were exposed to 0, 300, 900, 1200, 2400 ppm of Pistacia lentiscus L. (lentisk), Inula viscosa L. (strong-smelling inula), Quercus calliprinos Decne. (common oak) and Ceratonia siliqua L. (carob) extracts on growth medium (in vitro assay). In control treatments, 50-80% of IJs resumed development to J4, young and developed adult hermaphrodites, whereas all extracts, except for C. siliqua at 300 ppm, impaired IJ exsheathment and development. The highest concentration of I. viscosa extract (2400 ppm) had the strongest effect, killing 95% of exposed nematodes. Surviving nematodes did not recover, remaining at the IJ stage. Over the whole cycle, I. viscosa extract inhibited recovery to 25% or less, and did not allow full development to adulthood, whereas 65% of IJs in the control treatment recovered and resumed development, 12% reaching complete maturation within 72 h of incubation. When herbivorous S. littoralis larvae were fed with different plant extracts in vivo, I. viscosa had the strongest effect at concentrations above 300 ppm, with 90% of insect-invading IJs not developing to parasitic stages, whereas in the control treatment, 85% of IJs resumed development. Exposure to C. siliqua extract also inhibited exsheathment and development of 75% of the IJs. Half of those that resumed development reached full maturation. P. lentiscus and Q. calliprinos extracts also inhibited development of 50% IJs. Our results suggest that H. bacteriophora can be used to study herbal medication against parasites in animals.

Treatment of echinococcosis: albendazole and mebendazole--what else?

The search for novel therapeutic options to cure alveolar echinococcosis (AE), due to the metacestode of Echinococcus multilocularis, is ongoing, and these developments could also have a profound impact on the treatment of cystic echinococcosis (CE), caused by the closely related Echinococcus granulosus s.l. Several options are being explored. A viable strategy for the identification of novel chemotherapeutically valuable compounds includes whole-organism drug screening, employing large-scale in vitro metacestode cultures and, upon identification of promising compounds, verification of drug efficacy in small laboratory animals. Clearly, the current focus is targeted towards broad-spectrum anti-parasitic or anti-cancer drugs and compound classes that are already marketed, or that are in development for other applications. The availability of comprehensive Echinococcus genome information and gene expression data, as well as significant progress on the molecular level, has now opened the door for a more targeted drug discovery approach, which allows exploitation of defined pathways and enzymes that are essential for the parasite. In addition, current in vitro and in vivo models that are used to assess drug efficacy should be optimized and complemented by methods that give more detailed information on the host-parasite interactions that occur during drug treatments. The key to success is to identify, target and exploit those parasite molecules that orchestrate activities essential to parasite survival.

Modulation of inflammation response to murine cutaneous Leishmaniosis by homeopathic medicines: thymulin 5cH.

BACKGROUND: In previous studies, we observed that thymulin 5cH could modulate BCG (Bacillus Calmette-Guerin) induced chronic inflammation by increasing peritoneal B1 stem cells differentiation into phagocytes and improving phagocytosis efficiency. METHODS: We used the same protocol to study the effects of thymulin 5cH in the experimental murine Leishmaniasis, in order to elucidate some aspects of the parasite-host relation under this homeopathic treatment. Male Balb/c mice were orally treated with thymulin 5cH or vehicle during 60 days, after the subcutaneous inoculation of 2 × 10(6) units of Leishmania (L.) amazonensis into the footpad. Washied inflammatory cell suspension from peritoneal cavity, spleen, local lymph node and infected subcutaneous tissue were harvested after 2 and 60 days from infection to quantify the inflammation cells by flow cytometry and histometry methods. RESULTS: After a transitory increase of peritoneal T reg cells, treated mice presented, chronically, increase in the peritoneal and spleen B1 cells percentage (p = 0.0001) in relation to other cell types; more organized and exuberant inflammation response in the infection site, and decrease in the number of parasites per field inside the primary lesion (p = 0.05). No difference was seen in local lymph node histology. CONCLUSIONS: Thymulin 5cH is able to improve B1 cell activation and Leishmania (L) amazonensis phagocytosis efficiency in mice, similarly to that observed previously in BCG experimental infection.

Discovery of carbohybrid-based 2-aminopyrimidine analogues as a new class of rapid-acting antimalarial agents using image-based cytological profiling assay.

New antimalarial agents that exhibit multistage activities against drug-resistant strains of malaria parasites represent good starting points for developing next-generation antimalarial therapies. To facilitate the progression of such agents into the development phase, we developed an image-based parasitological screening method for defining drug effects on different asexual life cycle stages of Plasmodium falciparum. High-throughput screening of a newly assembled diversity-oriented synthetic library using this approach led to the identification of carbohybrid-based 2-aminopyrimidine compounds with fast-acting growth inhibitory activities against three laboratory strains of multidrug-resistant P. falciparum. Our structure-activity relationship study led to the identification of two derivatives (8aA and 11aA) as the most promising antimalarial candidates (mean EC50 of 0.130 and 0.096 µM against all three P. falciparum strains, selectivity indices >600, microsomal stabilities >80%, and mouse malaria ED50 values of 0.32 and 0.12 mg/kg/day, respectively), targeting all major blood stages of multidrug-resistant P. falciparum parasites.

Effect of crude extracts of Moringa stenopetala and Artemisia absinthium on parasitaemia of mice infected with Trypanosoma congolense.

BACKGROUND: Treatment of trypanosomosis is currently facing a number of problems including toxicity of trypanocidal drugs and development of resistance by the parasites. These limitations have prompted the search for alternative active substances (such as of natural origin). The purpose of the study was to investigate the effect of extracts of Moringa stenopetala and Artemisia absinthium on Trypanosoma congolense in mice. METHODS: Swiss white male mice aged 8-12 weeks were divided into six experimental groups of six animals. Water and methanol extracts of the two plants were prepared. T. congolense was isolated from cattle at Ghibe valley (Ethiopia). All experimental mice received approximately 1 x 10(5) trypanosomes in 0.2 ml of blood. Plant extracts were given orally to four groups (2 plant species and two extraction methods) at 400 mg/kg body weight for seven consecutive days. One group remained as distilled water treated control and the other as diminzene aceturate treated control. The effect of the extracts on levels of parasitaemia, body weight, packed cell volume (PCV) and mice survival was monitored for 25 days. RESULTS: All treatments have significantly reduced parasitaemia and helped improve body weight, PCV and survival of mice compared to the water-treated control (P < 0.01 in all cases). These effects were comparable to that with diminazene aceturate. No significant difference was observed in the reduction of parasitaemia between plant extract treatment groups. However, mice with extracts of A. absinthium had significantly higher body weight than those with extracts of M. stenopetala (P < 0.05). CONCLUSIONS: The two plants have antitrypanosomal potential against T. congolense by reducing the levels of parasitaemia, maintaining good PCV and body weight, and prolonging the lives of infected animals.

Aluminum induces cross-resistance of potato to Phytophthora infestans.

The phenomenon of cross-resistance allows plants to acquire resistance to a broad range of stresses after previous exposure to one specific factor. Although this stress-response relationship has been known for decades, the sequence of events that underpin cross-resistance remains unknown. Our experiments revealed that susceptible potato (Solanum tuberosum L. cv. Bintje) undergoing aluminum (Al) stress at the root level showed enhanced defense responses correlated with reduced disease symptoms after leaf inoculation with Phytophthora infestans. The protection capacity of Al to subsequent stress was associated with the local accumulation of H2O2 in roots and systemic activation of salicylic acid (SA) and nitric oxide (NO) dependent pathways. The most crucial Al-mediated changes involved coding of NO message in an enhanced S-nitrosothiol formation in leaves tuned with an abundant SNOs accumulation in the main vein of leaves. Al-induced distal NO generation was correlated with the overexpression of PR-2 and PR-3 at both mRNA and protein activity levels. In turn, after contact with a pathogen we observed early up-regulation of SA-mediated defense genes, e.g. PR1, PR-2, PR-3 and PAL, and subsequent disease limitation. Taken together Al exposure induced distal changes in the biochemical stress imprint, facilitating more effective responses to a subsequent pathogen attack.

Bioactivity against Bursaphelenchus xylophilus: Nematotoxics from essential oils, essential oils fractions and decoction waters.

The Portuguese pine forest has become dangerously threatened by pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Synthetic chemicals are the most common pesticides used against phytoparasitic nematodes but its use has negative ecological impacts. Phytochemicals may prove to be environmentally friendly alternatives. Essential oils (EOs) and decoction waters, isolated from 84 plant samples, were tested against B. xylophilus, in direct contact assays. Some successful EOs were fractionated and the fractions containing hydrocarbons or oxygen-containing molecules tested separately. Twenty EOs showed corrected mortalities ⩾96% at 2 µL/mL. These were further tested at lower concentrations. Ruta graveolens, Satureja montana and Thymbra capitata EOs showed lethal concentrations (LC100)<0.4µL/mL. Oxygen-containing molecules fractions showing corrected mortality ⩾96% did not always show LC100 values similar to the corresponding EOs, suggesting additive and/or synergistic relationships among fractions. Nine decoction waters (remaining hydrodistillation waters) revealed 100% mortality at a minimum concentration of 12.5µL/mL. R. graveolens, S. montana and T. capitata EOs are potential environmentally friendly alternatives for B. xylophilus control given their high nematotoxic properties. Nematotoxic activity of an EO should be taken in its entirety, as its different components may contribute, in distinct ways, to the overall EO activity.

Efficiency of ginger (Zingbar officinale) against Schistosoma mansoni infection during host-parasite association.

The possible protective effect of ethanolic extract of ginger against infection with Schistosome mansonii was evaluated in mice. The extract was given daily for 45 days beginning at either 2nd day or 45 days post infection. Oral supplementation of ginger extract to infected animals was effective in reducing worm burden and the egg load in the liver and intestine which coincided with the reduction in granuloma diameters. Ginger extract had also the effect to offset liver fibrosis in response to S. mansoni infection indicated by reduced liver hydroxyproline level and serum alpha-fetoprotein (AFP). The extract reduces some inflammatory mediators that play a crucial role in schistosomal liver fibrosis and its complications. These include liver xanthine oxidase (XO); nitric oxide (NO); tumour necrosis factor-alpha (TNF-α); immunoglobins E, G, and M (Ig-E, Ig-G and Ig-M, respectively), and interleukin 4, 10 and 12 (IL-4, IL-10 and IL-12, respectively). Administration of ginger extract ameliorated the infection-induced alterations in serum gamma-glutamyl transferase (GGT), alanine amintransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP). It was concluded that oral administration of ginger extract to S. mansoni infected mice could minimize the deleterious effects of this parasite on the vital functions of infected animals.

In vitro inhibition of Eimeria tenella invasion of epithelial cells by phytochemicals.

Resistance to coccidiostats and possible future restrictions on their use raise the need for alternative methods of reducing coccidiosis in poultry. The aim of this study was to evaluate the effect of selected phytochemicals on Eimeria tenella sporozoite invasion in vitro. Four phytochemicals were selected on the basis that they reduce the virulence of Eimeria spp. and/or provide immune modulatory benefits to host cells: betaine, carvacrol, curcumin and Echinacea purpurea extract (EP). Madin-Darby bovine kidney (MDBK) cells were covered by medium containing phytochemicals at the highest concentration which was non-toxic to the cells. Salinomycin 50 µg/ml was positive control; negative control was medium only. E. tenella (Houghton strain) sporozoites were added to wells and after incubation for 2, 4 or 20 h at 37°C, cells were fixed and stained with hematoxylin-eosin. Ten evenly spaced fields per well were photographed and the percentage of cells invaded by sporozoites was calculated and normalized to the control. At 2h, carvacrol, curcumin and EP showed a significantly lower percentage of sporozoite invasion than the untreated control; in contrast, betaine treatment represented a significantly higher invasion percentage. Combining carvacrol with EP inhibited E. tenella invasion more effectively than applying the compounds individually, but the further addition of curcumin did not reduce invasion further. In conclusion, this study shows that invasion of MDBK epithelial cells by E. tenella sporozoites is inhibited in the presence of carvacrol, curcumin, or EP and enhanced by betaine. There may be potential for developing these phytochemicals as anti-coccidial feed or water additives for poultry.