Browsing by Author "Miladi, Meriam"

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The aggregation pheromone phenylacetonitrile : joint action with the entomopathogenic fungus Metarhizium anisopliae var. acridum and physiological and transcriptomic effects on Schistocerca gregaria nymphs
(Elsevier, 2020) Abdellaoui, Khemais; Miladi, Meriam; Mkhinini, Marouane; Boughattas, Iteb; Ben Hamouda, Amel; Hajji-Hedfi, Lobna; Tlili, Haithem; Acheuk, Fatma
The combined use of entomopathogenic fungi and sublethal rate of chemical insecticides or other biological control agents have been proposed as an environmentally and sustainable strategy in the control of locust pests. In this paper, the quarter and the half of the recommended dose of Metarhizium anisopliae var. acridum (¼ and ½ Ma) and the aggregation pheromone (Phenylacetonitrile: PAN) were applied simultaneously and sequentially to Schistocerca gregaria fifth-instar nymphs. In addition, the physiological effects of PAN on locusts were assessed at the behavior, immune response, and biochemical level by evaluating for glutathione-S-transferase (GST), acetylcholinesterase inhibition (AChE), and malondialdehyde accumulation (MDA). Results showed that simultaneous application of PAN and the entomopathogenic fungus exhibited additive interaction. Synergistic interaction was also demonstrated when nymphs were exposed to PAN first, then treated with M. anisopliae var. acridum. Behavioral bioassay revealed that fifth-instar nymphs avoided the PAN odour and tended to remain away from the stimulus cup. In the choice assay, the pheromone significantly repelled the locusts at 2, 4, and 6 h of exposure which selected the PAN-free arena chamber. Moreover, treated nymphs become hyperactive and disoriented as evidenced by the cumulative distance travelled and the trajectory of locusts during the experiment. Immunological studies showed that PAN significantly decreased the differential haemocyte counts (prohemocytes and plasmatocytes) with a dose-response relationship. Data of biochemical analyzes showed that the PAN exposure reduced the activity of acetylcholinesterase and induced significantly the glutathione S-transferases and MDA concentration in the desert locust fifth-instar nymphs. Moreover, transcriptomic responses to the PAN exposure were evaluated using gene expression levels of CYP540 and GST. The transcript levels showed an up-regulation in GST expression level particularly in nymphs exposed for 4 and 6 h. A significant increase in CYP450 transcript level was also observed after 2 h of exposure, which decreased significantly after 4 and 6 h
The aggregation pheromone phenylacetonitrile: Joint action with the entomopathogenic fungus Metarhizium anisopliae var. acridum and physiological and transcriptomic effects on Schistocerca gregaria nymphs
(Academic Press Inc, 2020) Abdellaoui, K.; Miladi, Meriam; Mkhinini, M.; Boughattas, I.; Ben Hamouda, A.; Hajji-Hedfi, L.
The combined use of entomopathogenic fungi and sublethal rate of chemical insecticides or other biological control agents have been proposed as an environmentally and sustainable strategy in the control of locust pests. In this paper, the quarter and the half of the recommended dose of Metarhizium anisopliae var. acridum (¼ and ½ Ma) and the aggregation pheromone (Phenylacetonitrile: PAN) were applied simultaneously and sequentially to Schistocerca gregaria fifth-instar nymphs. In addition, the physiological effects of PAN on locusts were assessed at the behavior, immune response, and biochemical level by evaluating for glutathione-S-transferase (GST), acetylcholinesterase inhibition (AChE), and malondialdehyde accumulation (MDA). Results showed that simultaneous application of PAN and the entomopathogenic fungus exhibited additive interaction. Synergistic interaction was also demonstrated when nymphs were exposed to PAN first, then treated with M. anisopliae var. acridum. Behavioral bioassay revealed that fifth-instar nymphs avoided the PAN odour and tended to remain away from the stimulus cup. In the choice assay, the pheromone significantly repelled the locusts at 2, 4, and 6 h of exposure which selected the PAN-free arena chamber. Moreover, treated nymphs become hyperactive and disoriented as evidenced by the cumulative distance travelled and the trajectory of locusts during the experiment. Immunological studies showed that PAN significantly decreased the differential haemocyte counts (prohemocytes and plasmatocytes) with a dose-response relationship. Data of biochemical analyzes showed that the PAN exposure reduced the activity of acetylcholinesterase and induced significantly the glutathione S-transferases and MDA concentration in the desert locust fifth-instar nymphs. Moreover, transcriptomic responses to the PAN exposure were evaluated using gene expression levels of CYP540 and GST. The transcript levels showed an up-regulation in GST expression level particularly in nymphs exposed for 4 and 6 h. A significant increase in CYP450 transcript level was also observed after 2 h of exposure, which decreased significantly after 4 and 6 h. © 2020 Elsevier Inc
Olive leaf extracts toxicity to the migratory locust, locusta migratoria : histopathological effects on the alimentary canal and acetylcholinesterase and glutathione S-Transferases activity
(Springer, 2019) Abdellaoui, Khemais; Boussadia, O.; Miladi, Meriam; Boughattas, I.; Omri, Ghofrane; Mhafdhi, Mouna; Hazzoug, M.; Acheuk, Fatma; Brahem, M.
Physiological and biochemical effects of Olea europaea leaf extracts from four phenological growth stages on the oogenesis of female locust Locusta migratoria
(Wiley, 2018) Abdellaoui, Khemais; Hazzoug, Meriem; Boussadia, Olfa; Miladi, Meriam; Omri, Ghofrane; Acheuk, Fatma; Ben Halima‐Kamel, Monia; Brahem, Mohamed
Physiological, histopathological and cellular immune effects of Pergularia tomentosa extract on Locusta migratoria nymphs
(Elsevier, 2019) Miladi, Meriam; Abdellaoui, Khemais; Ben Hamouda, Amel; Boughattas, Iteb; Mhafdhi, Mouna; Acheuk, Fatma; Ben Halima-Kamel, Monia
The migratory locust Locusta migratoria (Orthoptera, Acrididae) is one of the most important pests due to its extensive and severe damage to crops in large parts of Africa and Asia. Biodegradable and ecologically natural products such as botanical insecticides are emerging candidates for replacement of usually applied chemical pesticides. The crude methanolic extract of Pergularia tomentosa (PME) was investigated for their toxicity and physiological aspects on L. migratoria nymphs. Results showed that treatment of newly emerged fourth and fifth instar nymphs resulted in significant mortality and significant repellent activity with an LC50 value of 0.18 and 0.38%, respectively, after seven days of treatment. The PME toxicity was also demonstrated by histopathological changes in the alimentary canal resulting in considerable disorganization and severe damage of the caeca and proventriculus structure. The extract induced cellular immune reactions which manifested by a significant decrease in the number of the differential haemocyte counts (prohemocytes and plasmatocytes) and important cell lysis. Data of biochemical analyses showed that the PME reduced the activity of acetylcholinesterase and induced the glutathione S-transferases. The neurotoxic effect was confirmed by the histological alterations in the brain structure, particularly in the neurosecretory cells showing typical signs of cell necrosis