Plants In Tunisia Research Articles

The cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is spreading in North Africa: first report in Tunisia

ABSTRACT Biological invasions by alien agricultural insect pests represent nowadays a major threat to the durability of agricultural systems. In this study, we report for the first time the presence of an invasive economic pest of ornamental and solanaceous crops in Tunisia: the cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae). It is native to America and has been spreading in Asia and the Mediterranean Basin. It was found in autumn 2021 forming dense colonies on Lantana camara L. (Verbenaceae) used for ornamental purposes in urban parks in the governorate of Tunis and on tomato Lycopersicon esculentum Mill. (Solanaceae) protected crops in the governorate of Sousse. Phenacoccus solenopsis was identified using an integrative approach based on morphological features and molecular analysis. Phylogenetic analysis using the mitochondrial Cytochrome Oxidase I (mtCOI) sequences of P. solenopsis populations from native and invaded areas retrieved in GenBank showed that Tunisian specimens might derive from an Asian population. We found that Nephus quadrimaculatus Herbst (Coleoptera: Coccinellidae: Scymninae) is the only natural enemy associated with this newly introduced pest so far. This is the first report of P. solenopsis attacking Lantana and tomato plants in Tunisia, and it should be considered as a potential threat to associated crops.

Effect of honey bee forage plants in Tunisia on diversity and antibacterial potential of lactic acid bacteria and bifidobacteria from Apis mellifera intermissa and its products.

Lactic acid bacteria and bifidobacteria (LAB and Bifido), isolated from the gastrointestinal tract of Apis mellifera intermissa (BGIT), honey (H), propolis (P) and bee bread (BB) of hives set in different vegetations (wildflowers, caraway, orange blossom, Marrubium vulgare, Eucalyptus and Erica cinerea), were subjected to analysis of their antibacterial potential. Isolates able to inhibit Staphylococcus aureus were selected and identified with MALDI-TOF MS leading to 154 strains representing 12 LAB and Bifido species. Lactiplantibacillus plantarum, Pediococcus pentosaceus and Enterococcus faecalis were predominantly found in all matrices. BGIT showed the highest LAB and Bifido diversity with exclusive occurrences of five species (including Bifidobacterium asteroides and Limosilactobacillus fermentum). Honey was the second origin harboring an important variety of LAB species of which Apilactobacillus kunkeei and Enterococcus mundtii were characteristic of both H and BGIT. Principal components analysis revealed associations between antibacterial activities of LAB and Bifido, matrices and honey bee forage plants. Inhibition trends of S. aureus and Citrobacter freundii were highlighted with: L. plantarum from BGIT, P, H of bees feeding on E. cinerea; Pediococcus pentosaceus from BGIT, P, BB associated with E. cinerea; and Bifidobacterium asteroides from BGIT/orange blossom system. However, Enterococcus faecium associated with BGIT/Eucalyptus system antagonized Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. Our findings highlighted noteworthy effects of bee forage plants on the antibacterial activity of LAB and Bifido. Our approach could be useful to identify multiple conditions promoting antibacterial potency of LAB and Bifido under the combined effects of feeding plants and living matrices.

Reuse of treated urban wastewater on the growth and physiology of Medicago sativa L. cv. Gea and Petroselinum crispum L. cv. Commun: correlation with oxydative stress and DNA damage.

The freshwater scarcity is one of the major environmental problems, which is why the water reuse has become a possible remedy to cope with the shortage of water needed for agriculture irrigation. This study focuses on the evaluation of the irrigation effect with treated effluent from wastewater treatment plant in Tunisia on parsley (Petroselinum crispum L. cv. Commun) used as human food and alfalfa (Medicago sativa L. cv. Gea) as animal food. In vitro germination test was conducted at different dilution levels of wastewater as rejected into the environment (25, 50, and 100%) and wastewater with further treatment (TWW). Results have shown that wastewater with dilution of 25% as well as TWW positively affected the physiological parameters in comparison with thedilutions 50 and 100%. However, the tap water (TW) applied as control treatment has shown the best effects. Oxidative stress evaluated by malondialdehyde (MDA) content was in agreement with the physiological results and showed that the most stressed seeds were those treated with thedilutions 50 and 100%. A pot trial was also conducted to evaluate the suitability of WW and TWW in comparison to TW. Results have shown that TWW is more adapted than WW for irrigation as an improvement of growth and physiological parameters was recorded. Oxidative stress assessed with MDA and proline content has shown that plants irrigated with WW significantly accumulate MDA and proline compared to TWW. The TW has shown the lowest values. DNA damage was evaluated by extraction and agarose gel electrophoresis. It has revealed degradation of DNA for plants irrigated with WW. According to these results, it can be concluded that TWW can be used for irrigation of plants destined for human or animal foods. So, it can be a hydric alternative to resolve the problem of water deficit in semi-arid countries.

Phytochemical Characterization, Antioxidant and Anti-Inflammatory Effects of Cleome arabica L. Fruits Extract against Formalin Induced Chronic Inflammation in Female Wistar Rat: Biochemical, Histological, and In Silico Studies.

In recent decades, the use of herbs and plants has been of great interest, as they have been the sources of natural products, commonly named as bioactive compounds. In specific, the natural compounds from the Capparaceae family which has been proved to have antioxidant, anti-inflammatory, antimicrobial and anti-carcinogenic activities, by several studies. Cleome arabica L. (CA) specie is the most used medicinal plants in Tunisia and elsewhere in North African countries for treatment of various diseases including diabetes, rheumatism, inflammation, cancer, and digestive disorders. The current work was undertaken to estimate the total phenolic, flavonoid and condensed tannin contents, to identify and quantify the polyphenolic compounds, and to evaluate the antioxidant and the anti-inflammatory proprieties of CA fruits extract against formalin induced chronic inflammation in Female Wistar rats. In fact, the antioxidant activity was tested by Diphenyl-1-Picrylhydrazyl free radical scavenging (DPPH), Ferric reducing antioxidant power (FRAP) and Nitric Oxide radical (NO·). Anti-inflammatory effect of fruits extract was examined using formalin (2%) induced paw edema in rats. Molecular docking tools were used to investigate the interaction of some compounds from CA fruits extract with the cyclooxygenase-2 (COX-2) target protein. Our results showed that, the total phenolic, flavonoid and tannins contents, which were assessed by the Folin-Ciocalteu, Quercetin, and Catechin methods, respectively, were 230.22 mg gallic acid equivalent/g dry weight (mg GAE/g DW), 55.08 mg quercetin equivalent/g dry weight (QE/g DW) and 15.17 mg catechin equivalents/g dry weight (CatE/g DW), respectively. HPLC analysis revealed the presence of five polyphenolic compounds whose catechin was found to be the most abundant compounds. The antioxidant activity of extract was quantified by DPPH, FRAP and NO· tests and IC50 reached the values of 3.346 mg/mL, 2.306 and 0.023 mg/mL, respectively. Cleome fruits ameliorated the histological integrity of the skin and alleviated the disruptions in hematological parameters (WBC, LYM, RBC, and HGB), inflammatory cytokines (IL-1β, IL-6, TNF-α), C-reactive protein, and some oxidative stress markers (TBARS (-49%) and AOPP (-42%) levels, SOD (+33%) and GPx (+75%) activities, and GSH (+49%) content) induced by formalin injection. Moreover, the in-silico investigation had shown that CA fruits extract compounds have a stronger interaction with COX-2 active site, more than the reference drug "indomethacin" (two H-bonds). Our research gives pharmacological backing to the healthcare utilization of Cleome plant in the treatment of inflammatory diseases and oxidative harm.

Mesembryanthemum crystallinum L.: A potential invasive plant in Tunisia

Biological invasions are considered as one of the most serious threats to the biodiversity. Mesembryanthemum crystallinum L. (Aizoaceae) is reported invasive in many regions over the world. This paper aim to monitor its distribution in the Kerkennah islands and update its invasive status. Field surveys, performed during May 2022, were achieved to record M. crystallinum occurrences and generate the plant distribution map. Field monitoring reveals that M. crystallinum is widespread and has the ability to grow in a broad range of disturbed habitats. The plant distribution pattern show that it often forms dense stands which allow it to inhibit the growth of other plants. Concidering its behaviour M. crystallinum should be considered as a potential invasive plant in Tunisia which requires the implementation of an appropriate management plan.

Predicting current and future distributions of Mentha pulegium L. in Tunisia under climate change conditions, using the MaxEnt model

Climate change and human activities have caused the degeneration of the natural habitats of medicinal plants. Mentha pulegium L. is one of the most common medicinal plants in Tunisia that features high economic and ecological values. Predicting species' suitable habitats, through modeling, has evolved as a useful tool for the assessment of resource conservation to protect medicinal plants. Herein, we used MaxEnt model to predict current and future distributions of M. pulegium under two representative concentration pathways (RCP2.6 and RCP8.5) for the years 2050 and 2070. MaxEnt modeling was in the “Excellent” category since all the AUCs were above 0.9. Results showed that high and moderate suitable habitats for the current distribution of M. pulegium encompassed ca. 9929 km2 and 16,423 km2, respectively. These areas are mainly located in North Tunisia. Precipitation of the coldest quarter (Bio19) was identified as the most critical factor shaping M. pulegium distribution. Compared to the current distribution, the highly and moderately suitable areas for M. pulegium under the two RCPs (RCP2.6 and RCP8.5) would decrease in the 2050s and 2070s. The model projected a shift of the suitable area from Northeastward to Center-eastward. These results may provide a useful tool for developing adaptive management strategies to enhance M. pulegium protection and sustainable utilization in the context of global climate change.

Identification and removal of sulfhydryl groups from wastewaters

Thiols represent a source of environmental pollution especially wastewater. This work proposed to study the elaboration of cellulose acetate polymer-based membranes for their application in the removal of a sulfhydryl groups of real biological treated wastewaters. The addition of nanoparticles to membranes improves the water purification capacity by promoting a good separation of sulfur, more particularly by ZnO-NPs. We used ultrafiltration membrane-assisted ZnO and TiO2 NPs application on real effluents from different biological treatment plants. We identified the hydrosulfite (thiol) group in wastewater and we used membrane processes ultrafiltration technique for sulfur removal. We evaluated the degradation of sulfur in biological treatment plants in Tunisia: The urban wastewater treatment plant or the conventional plant of Rades Malienne is a secondary biological wastewater treatment plant noted STEP1. The rural wastewater treatment plant based vertical flow planted with Phragmites australis from the Grombalia region noted STEP2 and rural wastewater treatment plant based horizontal flow planted with Phragmites australis from the Grombalia region noted STEP3. STEP1 is found to be more loaded with sulfur. Application of AC-ZnO membrane gives 99.07% and 99.55% of sulfur removal from wastewater of STEP1 and STEP3. STEP3 is 50 times less charged on sulfur than STEP1. We suggested that when the sulfur content is high, this leads to an increase in mineral elements. This could be explained by the interactions between thiols and the major elements that cause mineral pollution.

Essential oil of Rosmarinus officinalis induces in vitro anthelmintic and anticoccidial effects against Haemonchus contortus and Eimeria spp. in small ruminants

This work aimed to evaluate the valorisation of the volatile oil of “Rosmarinus officinalis L.”, a spontaneously growing medicinal plant in Tunisia, by studying its chemical composition, anthelmintic and anticoccidial potentials against Eimeria spp. and Haemonchus contortus at different essential oil concentrations. The main compounds of the R. officinalis essential oil identified by GC/MS were three monoterpenes: 1,8-cineole (52.06%), α-pinene (15.35%) and camphor (7.69%). The anticoccidial activity was estimated by the inhibition percentage of the oocyte sporulation in addition to the unsporulated and degenerated Eimeria oocysts using a haemocytometer after exposure to different essential oil concentrations. The essential oil was active against Eimeria spp. oocysts of sheep at IC<sub>50</sub> = 1.82 ug/ml. Therefore, the IC<sub>50</sub> values of the anticoccidial activity of this oil examined was 1.82 mg/ml. The anthelmintic efficacy of the rosemary volatile oil against Haemonchus contortus was realised by two in vitro tests: the egg hatch assay (EHA) and the adult worm’s motility assay (AWMA), by comparing this efficacy with albendazole (anthelmintic, of reference). In the egg hatch assay, the percentage of inhibition was observed at 16 mg/ml and was 73.76% after 2 days of incubation (IC<sub>50</sub> = 11.41 mg/ml) and for the adult worm’s motility assay, it was 100% inhibition.

Probabilistic seismic hazard assessment for two potential nuclear power plant sites in Tunisia

As part of a feasibility study for a potential electronuclear power plant in Tunisia, a new seismic catalogue and a new seismic source model have been proposed, for Tunisia and adjacent areas. These findings are used in this study to evaluate the seismic hazard for two selected nuclear power plant sites: Marsa-Douiba in the north and Skhira in the southeast. The investigations and the assessment are conducted at a regional scale. The location of these sites and the choice of a regional review extent allow us to consider the entire Tunisian territory as the study area and also to conduct the hazard evaluation at a ‘national level’. In this study, a probabilistic seismic hazard analysis is performed using the R-CRISIS software, and a logic tree is developed to capture uncertainties related to the characterisation of both seismic sources and ground-motion. First, a hazard map of Tunisia for the return period of 475 years is generated to compare it with the ones obtained within previous studies. Then, the 10,000-year return period is considered, and the recommendations of the International Atomic Energy Agency are applied to determine the uniform hazard spectrums and perform disaggregation for the selected sites.

Spatial distribution and ecological risk assessment of potentially toxic elements in agricultural soils, stream sediments, and plants around Lakhouat mine (northwestern Tunisia)

Potentially toxic element (PTE) distribution in 21 soil samples, 07 stream sediment samples and wheat near an abandoned mining site in the region of Lakhouat (northwestern Tunisia), sampled during dry season was investigated. The main objective was to characterize the environmental impacts of the former Pb-Zn extractive activity in the region. Chemical analysis revealed the presence of high PTE concentrations up to 28,040 mg kg−1 (Pb) and 94,420 mg kg−1 (Zn). Regarding nearby agricultural soils, PTE concentrations are exceeding the Tunisian standards for non-contaminated soils. The same contamination was detected in the stream sediments for which the Pb and Zn levels were found to be 54 to 147 times higher compared to the geochemical tolerance. Moreover, important concentrations of PTEs up to 638 mg kg−1 (Pb) and 939 mg kg−1 (Zn) were also found even in deep horizons (beyond 40 cm). Pollution index (PI) and Nemerow integrated pollution index (NIPI) gave several statuses of sediment quality revealing a polymetallic contamination dominated by the two elements Pb and Zn. The contamination found in Lakhouat soils is the result of the chemical and mineralogical composition of the soil and the infiltration of water loaded with PTEs from the discharges nearby. Extremely high PTE concentrations were also found in the roots (Pb = 1086 mg kg−1; Zn = 16.9 mg kg−1) and aerial parts (Pb = 3231 mg kg−1; Zn = 150 mg kg−1) of wheat grown on the contaminated soils, exceeding the thresholds for plant toxicity. Our study helps to assess the ecological risk due to potentially toxic elements contamination in agricultural soils, stream sediments and plants in Tunisia and other similar regions.

Sustainability assessment of a hybrid CSP/biomass. Results of a prototype plant in Tunisia

A renewable electricity system hybrid concentrated solar power/biomass power plantin Tunisia has been assessed. Life Cycle Assessment (LCA) and the Input-Output Analysis (IOA) methodologies have been performed to assess the environmental and socio-economic impacts of this technology in the Tunisian context. Application of these methodologies allowed computing environmental footprint, and the total economic stimulation produced by the increase in the demand for goods and services needed to build and operate this kind of plant. Results show for system operates in closed digester conditions value of 18.5 gCO2eq per kWh. In an open digester system, levels of GHG emissions are similar to fossil electricity generation with 550 gCO2eq per Kwh. For socioeconomic impacts, the multiplier effect of the direct investment for production of goods and services amounts is 2.43. Domestic value added created was quantified in a 42% (0.15 €2015/kWh) and employment creation in 532.9 FTE (0.006 FTE/MWh). Finally, the calculated abatement costs are low, 86 US$/tCO2eq. From the obtained results, it can be concluded that investments in this technology are then a cost-effective way of mitigating global warming emissions while also producing additional benefits in terms of value-added creation in the country and domestic employment generation.

Plant Extract Valorization ofMelissa officinalisL. for Agroindustrial Purposes through Their Biochemical Properties and Biological Activities

Lemon balm (Melissa officinalisL.) is one of the rare medicinal plants in Tunisia. It was found only in two sites in the north of Tunisia with a small number of plants. The study of germination under the NaCl and PEG effect showed that Tunisian lemon balm seeds were sensitive to saline and osmotic stress. Morphological and biochemical characterizations of TunisianM. officinaliswere performed. Results showed that the Tunisian populations presented plants with long, broad leaves and weak branching. The major constituent in leaf essential oil was germacrene-D with a percentage ranging from 29.17 to 24.6%, and the major fatty acids were polyunsaturated fatty acids, linoleic acid, ranging from 73.93 to 66.74%. The phenolic content ofM. officinalisextract varied significantly among origins which could explain the high variation in antiradical scavenging activity. The evaluation of allelopathic activities showed that the extract of the lemon balm leaves presented an allelopathic effect with the majority of the tested seeds.

Potential of common bean (Phaseolus vulgaris L.) root microbiome in the biocontrol of root rot disease and traits of performance

Common bean root microbiome was used to research for potential biocontrol agents of phytopathogenic fungi as Fusarium sp., Macrophomina sp., and Alternaria sp. causal agents of root rot disease on host plants. Therefore, a bacterial collection of 90 endophytic and rhizospheric isolates was established from field-grown common bean plants in Tunisia and screened for their antifungal activity against pathogenic fungal strains. Antifungal activity was checked at biochemical and genetic levels. Twelve bacterial strains exhibited up to 71% of inhibition of the three pathogenic strains of Fusarium sp., Macrophomina sp., and Alternaria sp. Biocontrol assays conducted under controlled conditions demonstrated that Bacillus amyloliquefaciens, Bacillus halotolerans, Bacillus velezensis, Agrobacterium fabrum, and Pseudomonas lini displayed the highest protective effect on common bean cv. Coco blanc. These bacterial strains were associated with significant plant growth promotion up to 217%, in comparison with control plants. Biochemical analysis of the antagonistic and plant growth promoting activity revealed the production of xylanases, chitinases, siderophore, hydrogen cyanide, phosphate-solubilizing activity, and the production of indole-3-acetic acid, particularly in Bacillus spp. strains. Polymerase chain reaction revealed the presence of lipopeptide biosynthetic genes encoding surfactin, iturin, bacillomycin, and fengycin. The study unveiled that common bean root microbiome contains potential bacterial strains that exhibit efficient biocontrol activity of Fusarium sp., Macrophomina sp., and Alternaria sp., and act as plant growth promoters. Considering various plant growth promoting and biocontrol traits, the study showed the superiority of the Bacillus spp. strains among different common bean root microbiomes.

Chorological and taxonomic notes on African plants, 4: Caryophyllales

ABSTRACTSome taxonomically critical and poorly known taxa from the order Caryophyllales are discussed. Both molecular and morphological data suggest that the chorologically distant populations of Tribulocarpus dimorphanthus in Namibia and East Africa are not uniform. Consequently, a new combination for Tetragonia somalensis, previously described from East Africa, is made within the genus Tribulocarpus (as T. somalensis). A single record of T. dimorphanthus from South Africa is suggested here to be erroneous, so that in its new circumscription, T. dimorphanthus is endemic to Namibia. The morphology of Caroxylon nollothense and related taxa is discussed, and C. angolense and C. luederitzense are placed in the synonymy of C. nollothense. New records from southern Africa are presented for the poorly known Dysphania pseudomultiflora. Suaeda spicata, so far known only from Spain and Morocco, is recorded for Tunisia. The composition of the genus Chenopodium s.l. in its recent circumscription is revised for the flora of the Mascarenes, and C. blomianum is recorded for Mauritius. Sesuvium verrucosum from the Americas is recognized as a naturalized species on the São Vicente Island (Cape Verde). Opuntia elatior is recognized as a naturalized plant in Tunisia. A diagnostic key to the naturalized cacti in northern Africa is provided. Sagina apetala is recorded for Tanzania and the whole eastern Africa. Mollugo verticillata is recorded from South Africa for the first time. Oxygonum sinuatum, a species native to eastern and southern Africa, is recorded as a common weed in inland areas of the Santo Antão Island (Cape Verde).

Phenolic profile, antioxidant capacity and antimicrobial activity of Calligonum arich L., desert endemic plant in Tunisia

Calligonum arich L. is an endemic plant belonging to the Polygonaceae family and growing in North Africa, particularly in Tunisia. This study aims to determine the phenolic profile and to evaluate the antioxidant and antibacterial activities of C. arich grown in Southern Tunisia environmental conditions. The samples were extracted using methanol solvent. Spectrophotometric methods were used to assess the total polyphenol content (TPC) and total flavonoid content (TFC) using respective standards (gallic acid and quercetin). Individual phenolic compounds were identified using high performance liquid chromatography (HPLC). The in vitro antioxidant capacity was studied adopting three different tests including total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-Azino-bis(3-ethylbenothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities. Results showed that total polyphenol content ranged from 32.02 mg GAE/g DW in roots to 34.27 mg GAE/g DW in leaves. Total flavonoid content ranged from 22.79 to 26.41 mg QE/g DW, respectively in stem and leaves. Qualitative and quantitative HPLC analysis revealed the presence of 14 phenolic compounds that varied significantly with plant parts. Interestingly, the antimicrobial test showed that C. arich leaves extract exhibited the highest antibacterial activity against five microorganisms (two Gram-positive and three Gram-negative bacteria). Moreover, both leaves and roots present a valuable source of phenolic compounds providing to C. arich a high antioxidant capacity with significant variability. This plant could be exploited as a potential source of natural bioactive molecules which confers on this species a greater nutritional value replacing synthetic antioxidants.

Investigation of flow dynamics of phosphate fertilizer production reactors using radiotracer technique

Radiotracer investigations were carried out in two identical phosphoric acid production reactors and a triple super phosphate (TSP) production reactor in three different plants in Tunisia. The main objective of the study was to investigate and compare their flow behavior and identify flow abnormalities, if any. Residence time distribution (RTD) of the process material (ore pulp) was measured in the three reactors using Iodine-131. The measured RTDs were treated and analyzed to obtain flow parameters such as the mean residence time (MRT), dead volume, and extent of bypassing. The treated RTD curves were modeled using a suitable mathematical model, and the values of the parameters were obtained. The results of the investigations were used to evaluate and compare the flow performance of the reactors, quantify the degree of mixing, and visualize the prevailing flow patterns. The results of the investigations are expected to be used to make necessary modifications to enhance the efficiency and optimize the performance of the reactors or the production process.

Sapovirus in Wastewater Treatment Plants in Tunisia: Prevalence, Removal, and Genetic Characterization.

Sapovirus (SaV), from the Caliciviridae family, is a genus of enteric viruses that cause acute gastroenteritis. SaV is shed at high concentrations with feces into wastewater, which is usually discharged into aquatic environments or reused for irrigation without efficient treatments. This study analyzed the incidence of human SaV in four wastewater treatment plants from Tunisia during a period of 13 months (December 2009 to December 2010). Detection and quantification were carried out using reverse transcription-quantitative PCR (RT-qPCR) methods, obtaining a prevalence of 39.9% (87/218). Sixty-one positive samples were detected in untreated water and 26 positive samples in processed water. The Dekhila plant presented the highest contamination levels, with a 63.0% prevalence. A dominance of genotype I.2 was observed on 15 of the 24 positive samples that were genetically characterized. By a Bayesian estimation algorithm, the SaV density in wastewater was estimated using left-censored data sets. The mean value of log SaV concentration in untreated wastewater ranged between 2.7 and 4.5 logs. A virus removal efficiency of 0.2 log was calculated for the Dekhila plant as the log ratio posterior distributions between untreated and treated wastewater. Multiple quantitative values obtained in this study must be available in quantitative microbial risk assessment in Tunisia as parameter values reflecting local conditions.IMPORTANCE Human sapovirus (SaV) is becoming more prevalent worldwide and organisms in this genus are recognized as emerging pathogens associated with human gastroenteritis. The present study describes novel findings on the prevalence, seasonality, and genotype distribution of SaV in Tunisia and Northern Africa. In addition, a statistical approximation using Bayesian estimation of the posterior predictive distribution ("left-censored" data) was employed to solve methodological problems related with the limit of quantification of the quantitative PCR (qPCR). This approach would be helpful for the future development of quantitative microbial risk assessment procedures for wastewater.

Estimation and experimental evaluation of the shortfall of photovoltaic plants in Tunisia: case study of the use of titled surfaces

To maximize the production of electrical energy in photovoltaic plants, the best solution is to use sun tracking systems whose panels are permanently exposed to solar radiation to ensure the best angle of inclination. These systems are expensive, their implementation is difficult, and their maintenance is complicated. The fixed inclination of the solar panels is easy to implement but its profitability is minimal. To solve this dilemma, the researchers propose to shift the panel’s angle of inclination over predetermined periods. In many countries, weather data measurements are either unavailable or lacking. So to fill this gap, we propose in this paper the development of mathematical models to calculate the best angle of inclination and the period of poise of this angle (month, season or other duration). The theoretical results obtained are validated by experimental tests and are conducted in three regions of Tunisia (North, Center and South). The objective is to determine, for each region, the optimal angle and the duration needed before switching to the next angle depending on the installation of fixed PV panels shortfalls.

Adaptive biochemical and physiological responses of Eriobotrya japonica to fluoride air pollution.

The biochemical and physiological effects of fluoride were investigated in loquat trees (Eriobotrya japonica) grown in the vicinity of a phosphate fertilizer plant in Tunisia. Photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities were assessed; along with photosynthetic pigments, lipid peroxidation, electrolytic leakage (EL) and total phenolic contents in foliage and roots of trees at different distances from the phosphate fertilizer plant. All assessed parameters showed significant discrepancies in comparison with unpolluted sites. Obtained results showed high oxidative stress indices including H2O2, lipid peroxidation, and EL, SOD, CAT and GPx activities and proline contents in leaves and roots at the polluted sites as compared to control. In contrast, leaf Pn, Gs, E and photosynthetic pigment contents were low as compared to the control. These results indicate that even though antioxidant responses increased near the factory, adverse effects on physiology were pronounced.

Staphylococcus aureus isolated from wastewater treatment plants in Tunisia: occurrence of human and animal associated lineages.

The objective was to characterize Staphylococcus aureus isolated from two wastewater treatment plants (WWTPs) located in Tunis City (Tunisia), during the period 2014-2015. Genetic lineages, antibiotic resistance mechanisms and virulence factors were determined for the recovered isolates. S. aureus isolates were recovered from 12 of the 62 wastewater samples tested (19.35%), and one isolate/sample was characterized, all of them being methicillin-susceptible (MSSA). Six spa types (t587, t674, t224, t127, t701 and t1534) were found among the 12 isolates, and the spa-t587, associated with the new sequence type ST3245, was the most predominant one (7 isolates). The remaining isolates were assigned to five clonal complexes (CC5, CC97, CC1, CC6 and CC522) according to the sequence-type determined and/or the spa-type detected. S. aureus isolates were ascribed to agrI (n = 3), agrII (n = 7) and agrIII (n = 1); however, one isolate was non-typeable. S. aureus showed resistance to (number of isolates): penicillin (12), erythromycin (7), tetracycline (one) and clindamycin (one). Among the virulence factors investigated, only one isolate harboured the tst gene, encoding the TSST-1 (toxic shock syndrome toxin 1). Despite the low number of studied isolates, the present study reports the occurrence of both human- and animal-associated S. aureus clonal complexes in WWTPs in Tunisia.