Meriem Msaad Guerfali

Dr. Meriem Msaad Guerfali

Ministry of Higher Education and Scientific Researcher
orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 April 2013 in Journal of Economic Entomology
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Journal Article
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HHHeithem Hamden
Heithem Hamden
MGMeriem Msaad Guerfali
Meriem Msaad Guerfali
SFSelma Fadhl
Selma Fadhl
MSMouldi Saidi
Mouldi Saidi
CCClaude Chevrier
Claude Chevrier
Successful mass rearing is crucial for sterile insect technique programs. It has been shown that the sterilizing process using gammaradiation results in damage

16 April 2020 in Foods
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Journal Article
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NGNils Th. Grabowski
Nils Th. Grabowski
STSéverin Tchibozo
Séverin Tchibozo
AAAmir Abdulmawjood
Amir Abdulmawjood
FAFatma Acheuk
Fatma Acheuk
MGMeriem Msaad Guerfali
Meriem Msaad Guerfali
MPMadeleine Plötz
Madeleine Plötz
Entomophagy is an ancient and actually African tradition that has been receiving renewed attention since edible insects have been identified as one of the solutions to improve global nutrition. As any other foodstuff, insects should be regulated by the government to ensure product quality and consumer safety. The goal of the present paper was to assess the current legal status of edible insects in Africa. For that, corresponding authorities were contacted along with an extensive online search, relying mostly on the FAOLEX database. Except for Botswana, insects are not mentioned in national regulations, although the definitions for “foodstuff” allow their inclusion, i.e., general food law can also apply to insects. Contacted authorities tolerated entomophagy, even though no legal base existed. However, insects typically appear in laws pertaining the use of natural resources, making a permit necessary (in most cases). Pest management regulation can also refer to edible species, e.g., locusts or weevils. Farming is an option that should be assessed carefully. All this creates a complex, nation-specific situation regarding which insect may be used legally to what purpose. Recommendations for elements in future insect-related regulations from the food hygiene point of view are provided.

7 May 2018 in PLOS ONE
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MGMeriem Msaad Guerfali
Meriem Msaad Guerfali
WDWafa Djobbi
Wafa Djobbi
KCKamel Charaabi
Kamel Charaabi
HHHeithem Hamden
Heithem Hamden
SFSalma Fadhl
Salma Fadhl
CCClaude Chevrier
Claude Chevrier
The Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is often referred to as the most severe agricultural pest. Its biological control is mainly through the Sterile Insect Technique (SIT). Colonization, mass-rearing conditions and the irradiation process impact the competitiveness of sterile males and disrupt symbiotic associations by favoring some bacterial species and suppressing others. Levels of Providencia species have been shown to fluctuate considerably in the gut of the medfly laboratory strain Vienna 8 under irradiation, increasing by up to 22%. This study aimed to determine the pathogenicity of Providencia rettgeri isolated from the gut of laboratory Vienna 8 medfly strains by examining the effects of 1) two different treatment doses on egg-hatching and development and 2) two infection methodologies (ingestion and injection) of male and female adults according to their mating status. Treatment of eggs with P. rettgeri (2%) significantly decreased the mean egg to pupae recovery rate. Our data showed significant high mortality in flies with both injection and ingestion after 24 hours without any effect of sex. Microbial counts demonstrated that the bacteria could proliferate and replicate in adult flies. There was a significant sex-dependent effect after infection, with mortality decreasing significantly for males more than females. Providencia rettgeri can be considered as a potential pathogen of C. capitata. Mating protected males and females against infection by P. rettgeri by triggering an immune response leading to double the levels of Cecropin being secreted compared to infected virgin adults, thus reducing the virulence of the bacteria.

10 September 2021 in PLOS ONE
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Journal Article
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MGMeriem Msaad Guerfali
Meriem Msaad Guerfali
KCKamel Charaabi
Kamel Charaabi
HHHaytham Hamden
Haytham Hamden
WDWafa Djobbi
Wafa Djobbi
SFSalma Fadhl
Salma Fadhl
ACAmeur Cherif
Ameur Cherif
Ceratitis capitata (medfly) is one of the most devastating crop pests worldwide. The Sterile Insect Technique (SIT) is a control method that is based on the mass rearing of males, their sterilization, and release in the field. However, the effectiveness of the technique depends on the quality of the released males and their fitness. We previously isolated and selected a probiotic bacteria (Enterobacter sp.), from wild-caught medflies, according to criteria that improved biological quality traits of reared medfly males.We firstly evaluated the impact of the irradiation on the expression of different immune and stress genes in the medfly sterile males. Expression was measured at differents time points ranging from 0 to 168 h after irradiation to capture the response of genes with distinct temporal expression patterns. Then, we supplemented the larval diet with previously isolated Enterobacter sp.strain, live and autoclaved at various concentrations to see whether the probiotic treatments affect, through their protective role, the gene expression level, and quality traits. The irradiation had significant effect on the genes attacin, cecropin, PGPR-LC, hsp23, and hsp70 level expression. The expression of attacin and PGPR-LC was up-regulated while that of cecropin was down-regulated. Hsp genes showed decreased levels between 0 and 18 h to peak at 72 h. However, the supplementation of the probiotic strain, either live or autoclaved, was statistically significant only for attacingene. However, significant interaction time x probiotic was noticed for attacin, cecropin, hsp23 and hsp70. The probiotic treatments also improved the quality control parameters like pupal weight. From this work we can conclude that a consortium of parabiotics (autoclaved probiotics) treatment will be recommended in insectaries considering both the beneficial effects on mass reared insects and its general safety for insectary workers and for environment.

11 January 2024 in Scientific Reports
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Journal Article
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HHHamden Haytham
Hamden Haytham
CKCharaabi Kamel
Charaabi Kamel
DWDjobbi Wafa
Djobbi Wafa
FSFadhel Salma
Fadhel Salma
BNBel Mokhtar Naima
Bel Mokhtar Naima
MGMeriem Msaad Guerfali
Meriem Msaad Guerfali
The sterile insect technique (SIT) remains a successful approach in managing pest insects. However, the long-term mass rearing and sterilizing radiation associated with SIT have been observed to induce physiological and ecological fitness decline in target insects. This decline may be attributed to various factors, including commensal microbiota dysbiosis, selection procedures, loss of heterozygosity, and other complex interactions.. There is evidence that the bacterial symbiont of insects may play critical roles in digestion, development, reproduction, and behavior. Probiotics are an increasingly common approach for restoring the intestinal microbiota structure and fitness parameters of sterile insects, particularly in the Vienna 8 genetic sexing strain (V8-GSS) of the Mediterranean fruit fly (medfly), Ceratitis capitata. Here, we explore the influence of the previously isolated bacterial strain, Lactococcus lactis, Enterobacter sp., and Klebsiella oxytoca, administration as probiotic consortia (LEK-PC) to the larvae and/or adult diet over the course of 20 rearing generations on fitness parameters. The experiment was carried out in four colonies: a control colony (C), one to which probiotics were not added, one to which probiotics were added to the larval medium (L+), one to which probiotics were added to the adult medium (A+), and one to which probiotics were added to both the larval and adult mediums (AL+). Emergence, flight ability, survival under stress conditions, and mating competitiveness, were all significantly improved by the LEK-PC treatment independently of the administration stage. The intestinal microbiota structure of various medfly V8-GSS colonies also underwent a significant shift, despite the fact that the core microbial community was unaffected by the LEK-PC administration stage, according to 16S metagenomics sequencing. Comparison of the metabolic function prediction and associated carbohydrate enzymes among colonies treated with “LEK-PC” showed an enrichment of metabolic functions related to carbohydrates, amino acids, cofactors, and vitamins metabolism, as well as, glycoside hydrolase enzymes in the AL+ colony compared to the control. This study enriches the knowledge regarding the benefits of probiotic treatment to modulate and restore the intestinal microbiota of C. capitata sterile males for a better effectiveness of the SIT.

1 January 2020 in Journal of Radiation Research and Applied Sciences
Verified
Journal Article
Open access
HHH. Hamden
H. Hamden
MGMeriem Msaad Guerfali
Meriem Msaad Guerfali
KCK. Charaabi
K. Charaabi
WDW. Djobbi
W. Djobbi
SFS. Fadhl
S. Fadhl
ACA. Cherif
A. Cherif
The Mediterranean fruit fly,Ceratitis capitata (Diptera: Tephritidae), is an important economic pest worldwide causing direct crop damage. One of the most successful control strategies for this pest is the application of the sterile insect technique. However, the deterioration of competitive mating performance against wild males was observed in Vienna8 Genetic Sexing Strain sterile males, which was aconsequence of irradiation. Therefore, beneficial probiotics were investigated to use as supplementation in sterile insect diets with properties on sexual performance enhancing which was the objective of the study. Hence, bacterial strains were isolated from C. capitata wild strain guts and were identified using the 16S-23S rRNA internal transcribed spacers region and 16S rRNA sequencing method. The isolated strains were evaluated for their probiotic potential by ‘in vitro’ and ‘in vivo’ tests. Finally, the candidate probiotic strains were selected by statistical analysis of their ‘in vitro’ and ‘in vivo’ tests data using principal component analysis (PCA). In conclusion, the combination of the two PCAs allowed the selection of Enterobacter sp., Lactococcus lactis and Klebsiella oxytoca as potential probiotic candidates to integrate into the larval diet.