43 research outputs found
Essential Oils and Biological Activities of <i>Eucalyptus falcata</i>, <i>E. sideroxylon</i> and <i>E. citriodora</i> Growing in Tunisia
No full textMany plants are able to synthesize essential oils (EOs), which play key roles in defense against weeds, fungi and pests. This study aims to analyze the chemical composition and to highlight the antioxidant, antimicrobial and phytotoxic properties of the EOs from Eucalyptus falcata, E. sideroxylon and E. citriodora growing in Tunisia. EOs were analyzed by gas chromatography coupled to mass spectrometry (GC/MS) and their antioxidant properties were determined by total antioxidant capacity (TAC), DPPH and ABTS assays. The phytotoxic potential was assessed against weeds (Sinapis arvensis, Phalaris canariensis) and durum wheat crop (Triticum durum) and compared to chemical herbicide glyphosate. The antifungal activity was investigated in vitro against eight target fungal strains. All EOs displayed a specific richness in oxygenated monoterpenes (51.3–90%) and oxygenated sesquiterpenes (4.8–29.4%), and 1,8-cineole, citronellal, citronellol, trans-pinocarveol, globulol, spathulenol and citronellyl acetate were the main constituents. Eucalyptus EOs exhibited remarkable antioxidant activity and E. citriodora oil exhibited significant activity when compared with E. falcata and E. sideroxylon EOs. The phytotoxic potential of the tested oils had different efficacy on seed germination and the growth of seedlings and varied among tested herbs and their chemical composition variability. Their effectiveness was better than that of glyphosate. At the post-emergence stage, symptoms of chlorosis and necrosis were observed. Furthermore, a decrease in chlorophyll and relative water content, electrolyte leakage and high levels of MDA and proline were indicators of the oxidative effects of EOs and their effectiveness as bioherbicides. Moreover, all the EOs exhibited moderate fungitoxic properties against all the tested fungal strains. Therefore, according to the obtained results, Eucalyptus EOs could have potential application as natural pesticides
Improvement of the Production of Entomopathogenic Proteases of Bacillus thuringiensis. K. Ennouri, R. Ben Ayed, H. Ben Hassen, H. Azzouz, and M.A. Triki. (Tunisia)
No full textBacillus thuringiensis (Bt) is a spore forming bacterium that produces an insecticidal crystalline protein
(ICP) making it a successful biopesticide. The ICPs are also referred to as Cry proteins and contain
delta-endotoxins which cause mortality of insects belonging to different orders such as Diptera,
Coleoptera and Lepidoptera. Bt subspecies produce also proteases which affect their entomotoxicity
toward targeted insects as proteolytic activities are strongly associated with Bt crystal protein.
Statistical techniques were applied to optimize the fermentation medium composition for the
production of bacterial proteases in shake-flask cultures. An experimental statistical design was
performed to evaluate the effects of different components on the concentration of proteolytic enzymes.
Preliminary results showed that starch and K2HPO4 are able to increase Bacillus sp. protease
production. In order to obtain more accurate results, interactions between ingredients were also studied.
In concordance with coefficient of determination (R²) value, considered as the most important criterion
for predictive model success, the best model demonstrated the effect of interactions and allowed precise
prediction of protease production. In fact, K2HPO4, KH2PO4, MgSO4, FeSO4 as well as Soybean meal
× starch and MnSO4 × starch interactions were shown to have active action on protease production.
This method revealed that limited number of experiments allowed useful results
MOLECULAR CHARACTERIZATION OF WILD GRAPES FROM NORTHEASTERN PART OF TURKEY
No full textKupe M., S. Ercisli, T. Jovanovic - Cvetkovic, S. P. Eyduran, R. B. Ayed (2021). Molecular characterization of wild grapes from northeastern part of TurkeyGenetika, Vol 53, No.1,93 -102
Artificial Intelligence to Improve the Food and Agriculture Sector
No full textThe world population is expected to reach over 9 billion by 2050, which will require an increase in agricultural and food production by 70% to fit the need, a serious challenge for the agri-food industry. Such requirement, in a context of resources scarcity, climate change, COVID-19 pandemic, and very harsh socioeconomic conjecture, is difficult to fulfill without the intervention of computational tools and forecasting strategy. Hereby, we report the importance of artificial intelligence and machine learning as a predictive multidisciplinary approach integration to improve the food and agriculture sector, yet with some limitations that should be considered by stakeholders
Morphological and Biochemical Diversity Among Autochthonous Grape Cultivars Morphologische und biochemische Vielfalt bei autochthonen Rebsorten
No full textNortheastern part of Turkey is rich in terms of autochthonous grape cultivars. In the region Yusufeli district has special importance for historical cultivation of grapevine. This small district has over fourteen local grape cultivars. Present study describe morphological and biochemical characteristics of nine autochthonous grape cultivars grown in Yusufeli district in Turkey. The standard Turkish grape cultivar 'Cavus' was also included experiment to make comparison with local ones. Bunch size, berry color, berry shape and usage are the searched main morphological characteristics. Phenolic compounds, organic acids, vitamin C and specific sugars were the main biochemical parameters. We found a wide variation among both morphological and biochemical characteristics. The cultivars showed low to medium bunch size. Chlorgenic acid (2.231-4.811 & x202f;mg/L), syringic acid (1.027-5.426 & x202f;mg/L) and rutin (1.013-1.129 & x202f;mg/L) were found the highest content in berries of cultivars. As expected, tartaric acid that characteristic for grape berries was the dominant (ranged from 1.826 to 3.336 & x202f;g/L) and followed by malic acid (ranged from 1.089 to 2.344 & x202f;g/L). The all autochthonous grape cultivars had glucose the highest concentration as major sugar and followed by fructose. It can be concluded that morphological and biochemical characteristics analyzed could be useful to give information about selection of the promising grape cultivars for breeders
Geographical Discrimination of Virgin Olive Oils from the Tunisian Coasts by Combining Fatty Acids and Phenolic Acids Profiles within a Multivariate Analysis
No full textEvaluation of Variability in Tunisian Olea europaea L. Accessions using Morphological Characters and Computational Approaches
No full textThe olive trees (Olea europaea L.) have been cultivated for millennia in the Mediterranean basin and its oil has been an important part of human nutrition in the region. In order to distinguish between olive accessions, morphological and biological characters have been widely and commonly used for descriptive purposes and have been used to characterize olive accessions. A comparative study of morphological characters of olive accessions grown in Tunisia was carried out and analyzed using Bayesian Networks (BN) and Principal Components Analysis (PCA). The obtained results showed that averages of fruit and kernel weights were 2.27 grams and 0.41 grams, respectively. Besides, a relatively moderate level of variation (51.22%) being explained by four Principal components. BN revealed that geographical localisation plays a role in the increase of tree habit, size of lenticels and leaf shape. A dendrogram has been carried out in the aim to classify studied olive accessions. We proposed a novel method of analysis based on the three-step scheme, in which first the data set is clustered, then olive tree features are evaluated. The studied accessions can be divided into four main groups by cutting the dendrogram at a similarity value of 0.645. Different relationships are studied and highlighted, and finally the collected features are subjected to a global principal component analysis. Obtained results confirmed that core surface was negatively correlated with geographical location (r = -0.52, p<0.05) and maturation period r = -0.539, p<0.05). Number of lenticels was positively correlated to lenticels size (r = 0.632, p<0.05). Core shape had a negative correlation with fruit shape (r = -0.759, p<0.05). On the basis of these findings, this research confirmed that morphological markers are a preliminary tool to characterize olive oil accessions.</jats:p
Contamination Assessment of Durum Wheat and Barley Irrigated with Treated Wastewater through Physiological and Biochemical Effects and Statistical Analyses
No full textThe present work focused on the impact of crop irrigation by treated wastewater (TWW) on soil fertility, in germination, and growth of two species of cereals (T. turgidum and H. vulgare). This investigation was conducted at the germination stage (controlled condition) and in pots containing a soil irrigated with wastewater in comparison with controlled soil. Germination rate, vigor index, seedling growth, total fresh mass, chlorophyll content, proline, ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT) activities were measured. Similar effects were shown on both species which emphasize the important role of antioxidant enzymes in the defense against oxidative stress induced by prolonged reuse of TWW. The disturbing effect of the reuse TWW on soil fertility, germination, and development of young plants (T. turgidum and H. vulgare) was linked to the presence of micropollutants in TWW. Data were analyzed by R language using a nonparametric statistical hypothesis test. These have caused the disorganization of many physiological mechanism targets, especially growth disorders observed under different abiotic stress conditions. In conclusion, high salt and heavy metal concentrations contained in the TWW are the major constraints related to the reuse of TWW. Hence, repetitive irrigation with this water can induce, at long term, soil contamination which can limit plant production and crop contamination
Experimental design and Bayesian networks for enhancement of delta-endotoxin production by Bacillus thuringiensis
No full textBacillus thuringiensis (Bt) is a Gram-positive bacterium. The entomopathogenic activity of Bt is related to the existence of the crystal consisting of protoxins, also called delta-endotoxins. In order to optimize and explain the production of delta-endotoxins of Bacillus thuringiensis kurstaki, we studied seven medium components: soybean meal, starch, KH2PO4, K2HPO4, FeSO4, MnSO4, and MgSO4 and their relationships with the concentration of delta-endotoxins using an experimental design (Plackett—Burman design) and Bayesian networks modelling. The effects of the ingredients of the culture medium on delta-endotoxins production were estimated. The developed model showed that different medium components are important for the Bacillus thuringiensis fermentation. The most important factors influenced the production of delta-endotoxins are FeSO4, K2HPO4, starch and soybean meal. Indeed, it was found that soybean meal, K2HPO4, KH2PO4 and starch also showed positive effect on the delta-endotoxins production. However, FeSO4 and MnSO4 expressed opposite effect. The developed model, based on Bayesian techniques, can automatically learn emerging models in data to serve in the prediction of delta-endotoxins concentrations. The constructed model in the present study implies that experimental design (Plackett—Burman design) joined with Bayesian networks method could be used for identification of effect variables on delta-endotoxins variation
Nutraceutical potentialities of Tunisian Argan oil based on its physicochemical properties and fatty acid content as assessed through Bayesian network analyses
No full textAbstract Background Argan oil is traditionally produced by cold pressing in South-western Morocco where rural population uses it as edible oil as well as for its therapeutic properties which give them in counterpart valuable income. Given the economical interest of this oil, several attempts of fraudulency have been registered in the world global market leading to loss of authenticity. Our purpose is to launch a program of Tunisian Argan oil valorization since trees from this species have been introduced sixty years ago in Tunisia. The first step was thus to characterize the physicochemical properties and determine the chemical composition of Tunisian Argan oil in order to assess its quality. Methods Physicochemical parameters of oil quality were determined according to the international standard protocols. Fatty acid content analysis of Argan oils was performed by gas chromatography coupled to mass spectrophotometry. A comparative study was realized among Tunisian, Moroccan and Algerian samples differing also by their extraction procedure. The impact of geographical localisation on the fatty acids composition was studied by statistical and modeling Bayesian analyses. Results Physicochemical parameters analysis showed interestingly that Tunisian Argan oil could be classified as extra virgin oil. Argan oil is mainly composed by unsaturated fatty acids (80%), mainly oleic and linoleic acid (linoleic acid was positively influenced by the geographical localization (r = 0.899, p = 0.038) and the P/S index (r = 0.987, p = 0.002)) followed by saturated fatty acids (20%) with other beneficial compounds from the unsaponifiable fraction like polyphenols and carotenoids. Together with fatty acid content, these minor components are likely to be responsible for its nutraceutical properties and beneficial effects. Conclusion Tunisian Argan oil displayed valuable qualitative parameters proving its competitiveness in comparison with Moroccan and Algerian oils, and could be therefore considered as extra virgin edible oil for nutraceutical purposes as well as for cosmetic use
