Changes in fatty acids profile,monosaccharide profile and protein content during batch growth of Isochrysis galbana (T.iso)

To investigate the nutritional value of the marine micro‐alga Isochrysis galbana Tahitian Isochrysis strain (T.iso) as an alternative feed for aquaculture during culture age, its biochemical composition was studied under autotrophic and controlled culture conditions at different growth stages: exponential phase, early and late stationary phases and decay phase. Analysis showed that C14:0, C16:0, C16:1, C18:4 (n‐3) and C22:6 (n‐3) were the most abundant fatty acids in this alga at different growth stages. The highest values of monounsaturated fatty acids were recorded at the late stationary and the decay phases. However, the highest levels of polyunsaturated fatty acids were observed at the early stationary phase. At all growth stages, I. galbana (T.iso) contained arabinose, xylose, mannose, galactose and glucose. Glucose represented the main sugar, and its content per dry alga biomass weight increased with increasing age of the culture and reached about fourfold in the decay phase. The maximum protein content was also observed during this last phase.     

Effectiveness of mating disruption with TUTATEC® dispensers against Tuta absoluta (Lepidoptera: Gelechiidae) in heated greenhouses in southern Tunisia

Phytoparasitica - Tomato production in geothermal greenhouses in Tunisia showed remarkable growth during the last decade and has been considered an important economic sector within the Tunisian...     

Transmission Efficiency of <Emphasis Type="Italic">Potato Leafroll Virus</Emphasis> by Four Potato Colonizing Aphid Species in Tunisian Potato Fields

This study investigated the transmission efficiency of Potato leafroll virus (PLRV) by four potato colonizing aphid species, Myzus persicae, Macrosiphum euphorbiae, Aphis gossypii and Aphis fabae, reported from leaves and yellow water trap. Physalis floridana was used as a test plant for virus transmission. DAS-ELISA was used for virus screening of samples as well as virus detection on the test plant after transmission experiment. A 2-h period was sufficient for the tested aphids to acquire PLRV virions. However, a difference in the transmission potential occurred according to the aphid species. The highest potential was recorded for M. persicae and M. euphorbiae, at 90 and 80%, respectively. For the first time, the study revealed the PLRV transmission efficiency of A. fabae, estimated at 50%. The lowest potential rate of 30% was recorded for A. gossypii. This study highlights the PLRV transmission capacities of four potato colonizing aphids suspected to play a key role in the spread of PLRV in potato seed production sites.     

Antioxidant and Antiproliferative Activity of <Emphasis Type="Italic">Diospyros lotus</Emphasis> L. Extract and Isolated Compounds

The object of the study was to determine the chemical composition of Diospyros lotus L. extract and their antioxidant and antiproliferative properties. Eight compounds were isolated from D. lotus and identified as gallic acid, methylgallate, ellagic acid, kaempferol, quercetin, myricetin, myricetin 3-O-β-glucuronide, and myricetin-3-O-α-rhamnoside. D. lotus extract tested in different in vitro systems (DPPH, ABTS, FRAP, and Fe²⁺ chelating activity assay) showed significant antioxidant activity. The potential antiproliferative properties of D. lotus extract and isolated compounds against nine human cancer cell lines such as COR-L23, CaCo-2, C32, ACHN, A375, A549, Huh-7D12, MCF-7, and LNCaP were investigated in vitro by SRB assay. D. lotus extract demonstrated the highest inhibitory activity against COR-L23 with an IC₅₀ value of 12.2 μg/ml. Among identified hydrolysable tannins, ellagic acid evidenced strong antiproliferative activity against both C32 and A375 cells with IC₅₀ values of 0.8 and 4.1 μg/ml, respectively. Interesting results were observed, also, with gallic acid that showed the highest cytotoxic activity against CaCo-2 (IC₅₀ 2.6 μg/ml). Overall, the results of this study suggest that D. lotus displays a good antioxidant activity and has antiproliferative effects. Both activities are related to identified phenolic compounds.     

Acidulated activation of phosphate rock enhances release,lateral transport and uptake of phosphorus and trace metals upon direct-soil application

Phosphate rock (PR) was activated via acidulation with HCl, EDTA, and oxalic acid to enhance its reactivity. The release, lateral transport, and uptake of phosphorus (P) along with trace metals from pristine and activated PRs were investigated in a soil micro-block system over a period of 27 days, using wheat (Triticum aestivum L.) plants. Significantly (p < 0.05) higher amounts of available soil P, Fe, Mn, and Zn were released from all the PRs after application to soil within first 9 days of seedling transplantation, while the release of other trace metals (Cd, Co, Cr, Cu, Ni, and Pb) was minimal (<1.2 mg kg^?1). On cumulative basis, APR-O (oxalic acid activated PR) was the most efficient amendment releasing 164% more available P, followed by APR-E (EDTA activated PR) releasing 130% more available P, compared to the pristine PR. Similar results were also observed in the release of available Fe, Mn, Zn, and other trace metals. The highest diffusive mass fluxes for available P, Mn, Fe, and Zn in soil were observed after 3 days of seedling transplantation, which reduced subsequently. The uptake of P, Fe, Mn, and Zn by wheat plants was increased by 394%, 715%, 92%, and 91%, respectively, in APR-O application compared to the pristine PR, while it was increased by 280%, 188%, 16%, and 27%, respectively, in APR-E application compared to the pristine PR. Subsequently, APR-O and APR-E amendments resulted in enhanced shoot lengths, root lengths, shoot dry matter, and root dry matter contents of wheat plants. Hence, it was concluded that activation of PR with oxalic acid and EDTA prior to direct soil application may enhance the reactivity of PR and could serve as a cost-effect fertilization strategy for higher wheat crop production.     

A remote sensing-based agricultural drought indicator and its implementation over a semi-arid region,Jordan

The objective of the study was to develop a remote sensing(i.e., Landsat-8 and MODIS)-based agricultural drought indicator(ADI) at 30-m spatial resolution and 8-day temporal resolution and also to evaluate its performance over a heterogeneous agriculture dominant semi-arid region in Jordan. Firstly, we used principal component analysis(PCA) to evaluate the correlations among six commonly used remote sensing-derived agricultural drought related variables. The variables included normalized difference water index(NDWI), normalized difference vegetation index(NDVI), visible and shortwave drought index(VSDI), normalized multiband drought index(NMDI), moisture stress index(MSI), and land surface temperature(LST). Secondly, we integrated the relatively less correlated variables(that were found to be NDWI, VSDI, and LST) to generate four agricultural drought categories/conditions(i.e., wet, mild drought, moderate drought, and severe drought). Finally, we evaluated the ADI maps against a set of 8-day ground-based standardized precipitation index values(i.e., SPI-1, SPI-2, …, SPI-8) by use of confusion matrices and observed the best results for SPI-4(i.e., overall accuracy and Kappa-values were 83% and 76%, respectively) and SPI-5(i.e., overall accuracy and Kappa-values were 85% and 78%, respectively). The results demonstrated that the method would be valuable for monitoring agricultural drought conditions in semi-arid regions at both a reasonably high spatial resolution(i.e., 30-m) and a short time period(i.e., 8-day).     

Effects of commonly used disinfectants on bacterial load,hatchability and survival of Bluefin Sea bream (Sparidentex hasta) eggs

The efficacy of four chemical reagents, iodophor, formalin, hydrogen peroxide and bronopol as fish egg surface disinfectants were evaluated in bluefin sea bream (Sparidentex hasta). Fertilized eggs were counted and subjected to a static bath dip treatment in different concentrations of the above chemicals for 4 min before being incubated at 20 ± 0.5°C for 40 h. Treatment efficacy of the different disinfectants was evaluated by assessing the bactericidal activity, egg hatch percentage and survival of larvae up to 3 days post hatch. Results showed that iodophor at medium concentrations (75 and 100 ppm) was the best of all tested disinfectants in bacterial killing ability (12% reduction in the bacterial counts), egg hatching per cent (99.8% and 99.6% respectively) and larval survival up to 3 days post hatch (50.8% and 54.8% respectively). Formalin was the second best disinfectant at levels of 100 and 150 ppm. Hydrogen peroxide gave good results compared with the control while, bronopol showed discouraging results. In conclusion, iodophor appeared to be suitable for bluefin sea bream eggs disinfection with a 4 min exposure to 75–100 ppm when applied 14–16 h after egg fertilization.     

Molecular polymorphism of cytoplasmic DNA in Ficus carica L.: Insights from non-coding regions of chloroplast DNA

The trnL (UAA) intron and the intergenic spacer between the 3′ exon of trnL (UAA) and trnF (GAA) sequences were used as genetic markers for differentiating Ficus carica cultivars and establishing refined genetic relationships. The study was based on 20 fig cultivars, collected from south and centre of Tunisia. Since, the intron was thought to be more variable among close relatives than is the chloroplast spacer. The size of these non-coding regions varied from 554 to 589 and from 989 to 1022 bases pairs for the intron and the combined sequences correspondingly. The average of GC content was 33.9% and 34.6% in the intron and the combined intron and spacer respectively. High values of A + T contents were detected in both data sets and may explain the high proportions of transversions founded. The observed variation pattern of plastid DNA provides evidence of an important genetic diversity. The overall transition/transversion bias (R) was 0.202 in the intron and 0.27 in the combined regions. The RI index of 0.592 indicates that these combined sequences have clearly more homoplasy then the intron (RI = 0.705) and spacer (RI = 0.777) sequences separately. Phylogenetic trees were generated based on maximum parsimony (MP) and neighbor-joining (NJ) analysis of the chloroplast sequences data. Results proved that a typically continuous genetic diversity characterizes the local fig germplasm. In fact, relationships inferred from the cpDNA analysis suggest several clades, which do not show geographical or tree sex correspondence. Although the level of apparent diversity is considerable, we may conclude that non-coding regions of chloroplast genome provide a new and practical opportunity to evaluate genetic diversity and to discriminate fig cultivars. Revealed cytoplasmic DNA markers are reliable to elaborate a molecular data base to conduct management and breeding programs on local fig germplasm.