Literature review on Water Productivity of date palm trees in Tunisian agro systems

The sustainability of agricultural productivity is closely related to the optimal exploitation of natural resources, namely the efficient water resources management.  The evaluation of the effectiveness of the adopted strategies and the applied practices and systems relies on a number of criteria and parameters of which water productivity indices represent the most relevant criteria. In this context, the present study aims to assess the water productivity for date palm cultivation in Tunisia based on an accurate literature review of the previously published scientific papers and reports related to the different studies carried out in these agro-oases regions of the country for the evaluation of the different indices of water productivity. This review represents the main baseline document highlighting in an exhaustive way the challenging features related to water productivity for date palm agro-systems. The outcome of this review indicates that (i) the cultivated date surface is  expanding, covering more than 58.000 ha with a total production of 355.000 tons in 2021(ii) the distribution of irrigation water is variable and irregular. iii) The reported water supply  for date palm range from 20,000 to 30,000 m3/ha while a number of scientific-based calculations estimate the crop water requirements for regular date palm production is  between 10,000 and 18,000 m3/ha (iv) the efficiency of water conservation techniques is related to numerous in farm factors related to the old traditional surface irrigation systems, to the soil salinization, alkalization and  permeability  loss and to the overexploitation issues of water resources that reaching is growing and may impact the productivity of date palms and sustainability of the production system (v) the estimation of the biophysical water productivity based on the reported data reaching barely  0.66kg/m3. This overview highlights the need for an accurate evaluation of the ecological efficiency of the used management measures to a clear appreciation of the  new strategies and policies to face the current constraints with regard to all different driving forces influencing water productivity both at the macro and micro scale

Étude des mécanismes moléculaires associés aux effets de l'ODN sur des cellules astrogliales et microgliales soumises à un stress oxydant : impact sur le métabolisme lipidique et la mort cellulaire

Neurodegenerative diseases are characterized by oxidative stress associated with mitochondrial damages leading to neuronal cell death. To mitigate these damages and promote neuronal cytoprotection and neurogenesis, endogenous (Neuropeptide: octadecaneuropeptide (ODN)) or exogenous (Polyphenols: resveratrol (RSV) and apigenin (API)) natural neurotrophic factors could be used as therapeutic agents to promote neuronal differentiation of immature and pluripotent stem cells. ODN is a peptide produced by astrocytes and known as a powerful neuroprotective agent. It is therefore of interest of studying its effects on the mobilization of calcium, its ability to protect neuronal cells against apoptosis death caused by hydrogen peroxide (H2O2) and evaluate its ability to stimulate neurogenesis by promoting neuronal differentiation. The effects of polyphenols (RSV, API), major compounds of the Mediterranean diet, on neurogenesis were also evaluated.The cytoprotective and/or differentiating properties of ODN (10-16 -10-8 M) and polyphenols (RSV: 6.25 -50 μM, API: 6.25 -50 μM) were mainly studied on murine N2a neuroblastoma cells but also on other murine (BV-2, C6) and human (SK-N-BE, CCF-STTG1) nerve lines. Cytoprotection was measured by various viability tests (FDA, MTT, DiOC6(3), propidium iodide). Differentiation was morphologically evaluated by the presence of neurites (axons and dendrites) and visualized by different microscopical techniques. Retinoic acid (RA: 6.25-50 μM) was used as a positive inductor of differentiation. The signaling pathways involved in neuronal differentiation have been characterized. We also studied the effect of ODN (10-14 M, 48 h) on the morphology, topography and activity of mitochondria and peroxisome during differentiation. These two organelles are involved in the metabolism of lipids (fatty acids, cholesterol).The results obtained show that ODN is able to promote the survival of N2a cells cultured under the conditions of acute oxidative stress induced by H2O2. In addition, ODN as well as polyphenols (RSV and API), which lack intrinsic cytotoxic effects, stimulate neurite outgrowth, indicating that they exert pro-differentiating neurotrophic effects. This effect of ODN involves activation of its metabotropic receptor associated with intracellular transduction pathways PKA, PKC and MAPK / ERKs. In addition, ODN stimulates the biogenesis of mitochondria and peroxisomes, essential organelles in axonal activity (axonal transport and renewal). The study of signaling pathways demonstrate that the trophic effects of RSV and API involve the activation of PKC, PKA and MAPK / ERK transduction pathways.Based on these results, the ODN release could be an endogenous protective mechanism in response to oxidative attacks and process of neurodegeneration, preventing cell death and promoting neuronal cell differentiation. Our work also highlights for the first time that polyphenols, in addition to their antioxidant activity, stimulate the formation, maturation and elongation of neurites of undifferentiated N2a cells. All of this work indicates that ODN neuropeptide and polyphenols (RSV and API) are potent neurotrophic agents. These molecules and/or their synthetic analogues may have pharmacological interest for treating neurodegenerative diseases by promoting neuroprotection, neuro-repair and neurogenesis.Les maladies neurodégénératives sont caractérisées par un stress oxydatif associé à des dommages mitochondriaux aboutissant à la mort des cellules neuronales. Pour atténuer ces dommages et favoriser la cytoprotection neuronale ainsi que la neurogenèse, des facteurs neurotrophiques naturels de type endogènes (Neuropeptide : octadécaneuropeptide (ODN)) ou exogènes (Polyphénols : resvératrol (RSV) et apigénine (API)) pourraient être utilisés comme agents thérapeutiques permettant de favoriser la différenciation neuronale des cellules souches immatures et pluripotentes. L’ODN est un peptide produit par les astrocytes et connu comme agent neuroprotecteur puissant d’où l’intérêt d’étudier ses effets sur la mobilisation du calcium, sa capacité à protéger les cellules neuronales contre la mort par apoptose générée par le peroxyde d’hydrogène (H2O2) et d’évaluer son pouvoir à stimuler la neurogenèse en favorisant la différenciation neuronale. Les effets des polyphénols (RSV, API), composés majeurs du régime méditerranéen, sur la neurogenèse ont été également évalués.Les propriétés cytoprotectrices et/ou différenciatrices de l’ODN (10-16 -10-8 M) et des polyphénols (RSV : 6.25 -50 µM ; API : 6.25 -50 µM) ont été essentiellement étudiées sur des cellules de neuroblastomes murins N2a mais aussi sur d’autres lignées nerveuses murines (BV-2, C6) et humaines (SK-N-BE ; CCF-STTG1). La cytoprotection a été mesurée par différents tests de viabilité (FDA, MTT, DiOC6(3), iodure de propidium). La différenciation a été évaluée morphologiquement par la présence de neurites (axones et dendrites) visualisés grâce à différentes techniques de microscopie. L’acide rétinoïque (AR : 6.25 -50 µM) a été utilisé comme contrôle positif d’induction de différenciation. Les voies de signalisation impliquées dans la différenciation neuronale ont été caractérisées. Nous avons aussi étudié l’effet de l’ODN (10-14 M, 48 h) sur la morphologie, la topographie et l’activité des mitochondries et des peroxysomes au cours de la différenciation. Ces deux organites sont impliqués dans le métabolisme des lipides (acides gras, cholestérol).Les résultats obtenus montrent que l’ODN est capable de promouvoir la survie des cellules N2a cultivées en condition de stress oxydatif aigue induit par le H2O2. De plus, l’ODN ainsi que les polyphénols RSV et l’API, qui sont dépourvus d’effet cytotoxique intrinsèque stimulent la croissance des neurites indiquant qu’ils exercent des effets neurotrophiques pro-différenciateurs. Cet effet de l’ODN met en jeu l’activation de son récepteur métabotropique associé aux voies de transduction intracellulaire PKA, PKC ainsi que MAPK / ERKs. De plus, l’ODN stimule la biogenèse des mitochondries et des peroxysomes, organites essentiels dans l’activité axonale (transport axonal et renouvellement). L’étude des voies de signalisation démontre que les effets trophiques du RSV et API mettent en jeu l’activation des voies de transduction de la PKC, PKA ainsi que celle des MAPK / ERKs.Sur la base de ces résultats, la libération d’ODN pourrait être un mécanisme endogène de protection en réponse aux attaques oxydatives et au processus de neurodégénérescence, empêchant la mort cellulaire et favorisant la différenciation des cellules neuronales. Nos travaux mettent aussi en évidence pour la première fois que les polyphénols en plus de leur action antioxydante stimulent la formation, la maturation et l’élongation des neurites des cellules N2a non différenciées. L’ensemble de ces travaux indique que le neuropeptide ODN et les polyphénols RSV et API sont de puissants agents neurotrophiques. Ces molécules présentent donc un intérêt pharmacologique en vue de leur utilisation et/ou de leurs analogues synthétiques pour traiter des maladies neurodégénératives en favorisant la neuroprotection, la neuro-réparation et la neurogenèse

Molecular mechanisms associated with the effects of ODN on astroglial and microglial cells stressed by an oxidative stress : impact on lipid metabolism and cell death

Les maladies neurodégénératives sont caractérisées par un stress oxydatif associé à des dommages mitochondriaux aboutissant à la mort des cellules neuronales. Pour atténuer ces dommages et favoriser la cytoprotection neuronale ainsi que la neurogenèse, des facteurs neurotrophiques naturels de type endogènes (Neuropeptide : octadécaneuropeptide (ODN)) ou exogènes (Polyphénols : resvératrol (RSV) et apigénine (API)) pourraient être utilisés comme agents thérapeutiques permettant de favoriser la différenciation neuronale des cellules souches immatures et pluripotentes. L’ODN est un peptide produit par les astrocytes et connu comme agent neuroprotecteur puissant d’où l’intérêt d’étudier ses effets sur la mobilisation du calcium, sa capacité à protéger les cellules neuronales contre la mort par apoptose générée par le peroxyde d’hydrogène (H2O2) et d’évaluer son pouvoir à stimuler la neurogenèse en favorisant la différenciation neuronale. Les effets des polyphénols (RSV, API), composés majeurs du régime méditerranéen, sur la neurogenèse ont été également évalués.Les propriétés cytoprotectrices et/ou différenciatrices de l’ODN (10-16 -10-8 M) et des polyphénols (RSV : 6.25 -50 µM ; API : 6.25 -50 µM) ont été essentiellement étudiées sur des cellules de neuroblastomes murins N2a mais aussi sur d’autres lignées nerveuses murines (BV-2, C6) et humaines (SK-N-BE ; CCF-STTG1). La cytoprotection a été mesurée par différents tests de viabilité (FDA, MTT, DiOC6(3), iodure de propidium). La différenciation a été évaluée morphologiquement par la présence de neurites (axones et dendrites) visualisés grâce à différentes techniques de microscopie. L’acide rétinoïque (AR : 6.25 -50 µM) a été utilisé comme contrôle positif d’induction de différenciation. Les voies de signalisation impliquées dans la différenciation neuronale ont été caractérisées. Nous avons aussi étudié l’effet de l’ODN (10-14 M, 48 h) sur la morphologie, la topographie et l’activité des mitochondries et des peroxysomes au cours de la différenciation. Ces deux organites sont impliqués dans le métabolisme des lipides (acides gras, cholestérol).Les résultats obtenus montrent que l’ODN est capable de promouvoir la survie des cellules N2a cultivées en condition de stress oxydatif aigue induit par le H2O2. De plus, l’ODN ainsi que les polyphénols RSV et l’API, qui sont dépourvus d’effet cytotoxique intrinsèque stimulent la croissance des neurites indiquant qu’ils exercent des effets neurotrophiques pro-différenciateurs. Cet effet de l’ODN met en jeu l’activation de son récepteur métabotropique associé aux voies de transduction intracellulaire PKA, PKC ainsi que MAPK / ERKs. De plus, l’ODN stimule la biogenèse des mitochondries et des peroxysomes, organites essentiels dans l’activité axonale (transport axonal et renouvellement). L’étude des voies de signalisation démontre que les effets trophiques du RSV et API mettent en jeu l’activation des voies de transduction de la PKC, PKA ainsi que celle des MAPK / ERKs.Sur la base de ces résultats, la libération d’ODN pourrait être un mécanisme endogène de protection en réponse aux attaques oxydatives et au processus de neurodégénérescence, empêchant la mort cellulaire et favorisant la différenciation des cellules neuronales. Nos travaux mettent aussi en évidence pour la première fois que les polyphénols en plus de leur action antioxydante stimulent la formation, la maturation et l’élongation des neurites des cellules N2a non différenciées. L’ensemble de ces travaux indique que le neuropeptide ODN et les polyphénols RSV et API sont de puissants agents neurotrophiques. Ces molécules présentent donc un intérêt pharmacologique en vue de leur utilisation et/ou de leurs analogues synthétiques pour traiter des maladies neurodégénératives en favorisant la neuroprotection, la neuro-réparation et la neurogenèse.Neurodegenerative diseases are characterized by oxidative stress associated with mitochondrial damages leading to neuronal cell death. To mitigate these damages and promote neuronal cytoprotection and neurogenesis, endogenous (Neuropeptide: octadecaneuropeptide (ODN)) or exogenous (Polyphenols: resveratrol (RSV) and apigenin (API)) natural neurotrophic factors could be used as therapeutic agents to promote neuronal differentiation of immature and pluripotent stem cells. ODN is a peptide produced by astrocytes and known as a powerful neuroprotective agent. It is therefore of interest of studying its effects on the mobilization of calcium, its ability to protect neuronal cells against apoptosis death caused by hydrogen peroxide (H2O2) and evaluate its ability to stimulate neurogenesis by promoting neuronal differentiation. The effects of polyphenols (RSV, API), major compounds of the Mediterranean diet, on neurogenesis were also evaluated.The cytoprotective and/or differentiating properties of ODN (10-16 -10-8 M) and polyphenols (RSV: 6.25 -50 μM, API: 6.25 -50 μM) were mainly studied on murine N2a neuroblastoma cells but also on other murine (BV-2, C6) and human (SK-N-BE, CCF-STTG1) nerve lines. Cytoprotection was measured by various viability tests (FDA, MTT, DiOC6(3), propidium iodide). Differentiation was morphologically evaluated by the presence of neurites (axons and dendrites) and visualized by different microscopical techniques. Retinoic acid (RA: 6.25-50 μM) was used as a positive inductor of differentiation. The signaling pathways involved in neuronal differentiation have been characterized. We also studied the effect of ODN (10-14 M, 48 h) on the morphology, topography and activity of mitochondria and peroxisome during differentiation. These two organelles are involved in the metabolism of lipids (fatty acids, cholesterol).The results obtained show that ODN is able to promote the survival of N2a cells cultured under the conditions of acute oxidative stress induced by H2O2. In addition, ODN as well as polyphenols (RSV and API), which lack intrinsic cytotoxic effects, stimulate neurite outgrowth, indicating that they exert pro-differentiating neurotrophic effects. This effect of ODN involves activation of its metabotropic receptor associated with intracellular transduction pathways PKA, PKC and MAPK / ERKs. In addition, ODN stimulates the biogenesis of mitochondria and peroxisomes, essential organelles in axonal activity (axonal transport and renewal). The study of signaling pathways demonstrate that the trophic effects of RSV and API involve the activation of PKC, PKA and MAPK / ERK transduction pathways.Based on these results, the ODN release could be an endogenous protective mechanism in response to oxidative attacks and process of neurodegeneration, preventing cell death and promoting neuronal cell differentiation. Our work also highlights for the first time that polyphenols, in addition to their antioxidant activity, stimulate the formation, maturation and elongation of neurites of undifferentiated N2a cells. All of this work indicates that ODN neuropeptide and polyphenols (RSV and API) are potent neurotrophic agents. These molecules and/or their synthetic analogues may have pharmacological interest for treating neurodegenerative diseases by promoting neuroprotection, neuro-repair and neurogenesis

Biomarkers of Amyotrophic Lateral Sclerosis: Current Status and Interest of Oxysterols and Phytosterols

Amyotrophic lateral sclerosis (ALS) is a non-demyelinating neurodegenerative disease in adults with motor disorders. Two forms exist: a sporadic form (90% of cases) and a family form due to mutations in more than 20 genes including the Superoxide dismutase 1, TAR DNA Binding Protein, Fused in Sarcoma, chromosome 9 open reading frame 72 and VAPB genes. The mechanisms associated with this pathology are beginning to be known: oxidative stress, glutamate excitotoxicity, protein aggregation, reticulum endoplasmic stress, neuroinflammation, alteration of RNA metabolism. In various neurodegenerative diseases, such as Alzheimer’s disease or multiple sclerosis, the involvement of lipids is increasingly suggested based on lipid metabolism modifications. With regard to ALS, research has also focused on the possible involvement of lipids. Lipid involvement was suggested for clinical arguments where changes in cholesterol and LDL/HDL levels were reported with, however, differences in positivity between studies. Since lipids are involved in the membrane structure and certain signaling pathways, it may be considered to look for oxysterols, mainly 25-hydroxycholesterol and its metabolites involved in immune response, or phytosterols to find suitable biomarkers for this pathology

Bacteria associated with the rhizosphere of manganese-deficient date palms affected by Brettle Leaf Disease

[EN] Brittle leaf disease or "Maladie des feuilles cassantes" (MFC) is a disorder affecting date palm (Phoenix dactylifera) orchards in oases of southern Tunisia. No causal pathogen has yet been identified, despite search for nematodes, fungi, bacteria, viruses and viroids. Although the soils of the oases in which affected palms grow have similar contents of total and exchangeable manganese (Mn) compared with oases with no disease, the leaflets of affected palms are deficient in this element. Here, we characterized the bacterial flora in the rhizosphere of three MFC-affected date palms and three non-affected controls. Our results show a high bacterial diversity in the date palm rhizosphere. From 201 clones corresponding to a 16S rDNA PCR fragment, we identified 177 different bacterial phylotypes. Some of them corresponded potentially to Mn-oxidizing bacteria that may be involved in soil Mn oxidation and, consequently, deplete this micronutrient in MFC-affected date palms. More detailed studies are necessary to establish the exact role of these bacteria in the disease syndrome.Work supported by grants AGL2007-65653-C02-01 (JAD) and AGL2007-65653-C02-02 (NDV) from Ministerio de Educacion y Ciencia (MEC) from Spain and ACOMP07/261 (JAD) from Generalitat Valenciana. JM was the recipient of a predoctoral fellowship from MEC. We thank Holly Kuzmiak-Ngiam (University of Rochester, USA) for critical reading of the manuscript.Marques, J.; Duran Vila, N.; Namsi, A.; Bove, J.; Daros Arnau, JA. (2012). Bacteria associated with the rhizosphere of manganese-deficient date palms affected by Brettle Leaf Disease. Journal of Plant Pathology. 94(1):157-169. https://doi.org/10.4454/jpp.fa.2011.004S15716994

Variability of physicochemical properties of ‘Deglet Nour’ date fruits collected from different oases in Djerid Region, Tunisia

Purpose : Quality and physical characteristics of date palm changes during growth and maturation stages of fruits in main production areas in the south of Tunisia. Research Method: The effect of season, ripening date and climatic conditions (temperature and relative humidity) on physicochemical characteristics of fresh dates “Deglet Nour” grown at four different oases were evaluated using multivariate analysis. Main findings: Dates from Traditional Mountain Oases (TMO) had the highest values of length, width, weight, moisture content for the two seasons. Those from Modern Palm Plantation (MPP) had the highest values of fiber content, water activity, glucose and fructose in 2014. In 2014 and 2015, date palm fruits of Modern Continental Oases (MCO) had the highest values of sucrose. The lower values of the different parameters were registered for dates from Traditional Continental Oases (TCO). Meteorological data from the experimental station recorded higher temperature and relative humidity during fruit maturation (July, August and September) in 2014 compared to 2015. Results showed that the good quality of dates was obtained in oases TMO that had higher relative humidity and lower temperature compared to other oases (MPP, MCO, and TCO). Such changes may have resulted from earlier pollination and higher temperatures during the maturation period. Considering the two seasons 2014 and 2015, the highest thermal coefficients were observed in MCO (3726 and 3704, respectively) and the lower ones in TCO (3083 and 3025, respectively). Research limitation: No limitations were founded. Originality/Value: Seasons and oases climate significantly affected the physical and biochemical quality characteristics of date palm fruits. This engendered in the longest maturity period recorded in TCO. MPP where we recorded the highest spring temperatures, showed the shorted development cycle

Chemical fruit composition of Tunisian date palm 'Deglet Nour' collected at maturation from four different oases in Djerid region

peer reviewedThe Deglet Nour in Djerid Region is the most popular variety of date palm. Our study aims to provide information about physicochemical properties of dates Deglet Nour at Tamar stage from different oases in Djerid Region. The date fruits were collected from four different oases at different locations in South Tunisia: Traditional Continental Oasis (TCO), Traditional Mountain Oasis (TMO), Modern Continental Oasis (MCO), and Modern Palm Date Plantation (MPP). Fruit size and weight, Total Soluble Solids (TSS), pH, Titratable Acidity (TA), Dietary Fiber (DF), Protein content (MPT) and sugars were studied. The obtained results showed that physiochemical properties varied significantly according to the locations. Fruits from all oasis may be considered suitable for marketing as Deglet Nour dates from well-known producing areas. TSS, pH, TA, MPT and sugars were significantly important in dates from TMO oasis