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...     

Verte and Romaine lettuce varieties (Lactuca sativa) show differential responses to high NaCl concentrations

In this study, we report on the relationship between individual antioxidant carotenoids, phenolic fractions, and flavonoids and attenuating NaCl toxicity in two contrasting varieties of lettuce (Lactuca sativa L., var. Verte and Romaine), as a means of developing more precise targets for lettuce breeding. In seedling leaves, carotenoid levels increased under NaCl stress in Verte, but remained unchanged in Romaine. Chlorogenic acid (CGA), a soluble polyphenol abundantly present in leaves, was the only phenolic acid that accumulated significantly in both varieties and was predominant under salinity. Remarkably, CGA was more prominent in Verte than Romaine at moderate salinity levels (100 mM). Foliar flavonoid levels were also differentially increased in both seedling types grown under 100 mM NaCl, but dropped significantly in both varieties under 200 mM NaCl. Germination, which was overall more salt‐resistant in Romaine, was significantly increased under salt stress by application of low dosage (10^–6 to10^–5 M) of CGA to Verte, but not to Romaine. These results suggest that CGA is involved in modulating NaCl‐induced oxidative‐stress responses during seed germination in Verte.     

Potential of Exopolysaccharide from Porphyridium marinum to Contend with Bacterial Proliferation,Biofilm Formation,and Breast Cancer

Exopolysaccharide (EPS) from marine microalgae are promising sources of a new generation of drugs. However, lot of them remain to be discovered and tested. In this study, EPS produced by Porphyridium marinum and its oligomers prepared by High Pressure Homogenizer have been tested for different biological activities, i.e., antibacterial, anti-fungal and antibiofilm activities on Candida albicans, as well as for their effects on the viability of murine breast cancer cells. Results have shown that all EPS samples present some biological activity. For antibacterial and antibiofilm activities, the native EPS exhibited a better efficiency with Minimum Inhibitory Concentration (MIC) from 62.5 µg/mL to 1000 µg/mL depending on the bacterial strain. For Candida albicans, the biofilm formation was reduced by about 90% by using only a 31.3 µg/mL concentration. Concerning breast cancer cells, lower molar masses fractions appeared to be more efficient, with a reduction of viability of up to 55%. Finally, analyses of polymers composition and viscosity measurements were conducted on all samples, in order to propose hypotheses involving the activities caused by the intrinsic properties of polymers.     

Thrips (Thysanoptera: Thripidae) in northern Tunisian citrus orchards: population density,damage and insecticide trial for sustainable pest management

Phytoparasitica - Thrips (Thysanoptera: Thripidae) have been considered serious pests infesting a wide range of host plants around the world, which has also been the case for citrus trees in...     

Optimization of lipase-catalyzed synthesis of acetylated tyrosol by response surface methodology

The ability of a noncommercial immobilized lipase from Staphylococcus xylosus (SXLi) to catalyze the transesterification of tyrosol and ethyl acetate was investigated. Response surface methodology was used to evaluate the effects of the temperature (40-60 degrees C), the enzyme amount (50-500 UI), and the ethyl acetate/hexane volume ratio (0.2-1) on the tyrosol acetylation conversion yield. Two independent replicates were carried out under the optimal conditions predicted by the model (reaction temperature 54 degrees C, enzyme amount 500 UI, and volume ratio ethyl acetate/hexane 0.2). The maximum conversion yield reached 95.36 +/- 3.6%, which agreed with the expected value (96.8 +/- 3.7%). The ester obtained was characterized by spectroscopic methods. Chemical acetylation of tyrosol was performed, and the products were separated using HPLC. Among the eluted products from HPLC, mono- and diacetylated derivatives were identified by positive mass spectrometry. Tyrosol and its monoacetylated derivative exert similar antiradicalar activity on 2,2-diphenyl-1-picrylhydrazyle.     

Comparison on the total phenol contents and the color of fresh and infrared dried olive leaves

The color (L*, a*, b* parameters), the total phenols content and the global chemical composition (moisture, protein, fat, carbohydrates and ash) of four fresh varieties of olive leaves (Chemlali, Chemchali, Zarrazi and Chetoui) were determined. Fresh olive leaves are characterized by a green color (greenness parameter, a*, varying from ?5.01 ± 0.26 to ?9.14 ± 1.21), an intermediate moisture content (0.85 to 1.00 g/g dry matter, i.e. 46 to 50 g/100 g fresh matter) and a variable amount of total phenols according to the olive leaf variety (from ≈2.32 to ≈1.40 g caffeic acid/100 g dry matter).Fresh leaves were submitted to blanching and/or infrared drying at 40, 50, 60 and 70 °C in order to be stabilized by reducing their moisture contents. The impact of IR drying temperature on some quality attributes (color, total phenols and moisture rate removal) was evaluated. Nevertheless, the effect of prior blanching treatment on the quality attributes of dried leaves is less significant and it depends on the olive leaf variety. The infrared drying induces a considerable moisture removal from the fresh leaves (more than 85%) and short drying durations (varying from ≈162 at 40 °C to 15 min at 70 °C). IR drying temperature showed a significant effect of on total phenols content and the color of the leaves whatever the leaf variety. In fact, total phenols content of dried olive leaves increased if compared to fresh ones. For example, total phenols of Chemlali leaves increased from 1.38 ± 0.02 (fresh leaves) to 2.13 ± 0.29 (dried at 40 °C) and to 5.14 ± 0.60 g caffeic acid/100 g dry matter (dried at 70 °C). IR drying allows preserving the greenness color of fresh leaves and enhancing their luminosity. It could be suggested for preserving olives leaves before their use in food or cosmetic applications.     

不同杀菌剂对玉米弯孢叶斑病菌的毒力测定

以分生孢子萌发法和生长速率抑制法比较了5种杀菌剂对玉米弯孢叶斑病菌(Curvularialunata(Boed)Wakker)的毒力作用。结果表明,不同杀菌剂、同种杀菌剂不同系列浓度之间存在差异,且同种杀菌剂对分生孢子与菌丝毒力作用不同。分生孢子萌发试验中,百菌清、退菌特、多菌灵、粉锈宁和代森锰锌的EC50分别为0.171,0.064,0.241,0.193和0.591mg/mL;生长速率抑制试验中,百菌清、退菌特、多菌灵、粉锈宁和代森锰锌的EC50分别为0.094,0.039,0.026,0.284和0.159mg/mL。     

Pyogenic bacterial infections in humans with MyD88 deficiency

MyD88 is a key downstream adapter for most Toll-like receptors (TLRs) and interleukin-1 receptors (IL-1Rs). MyD88 deficiency in mice leads to susceptibility to a broad range of pathogens in experimental settings of infection. We describe a distinct situation in a natural setting of human infection. Nine children with autosomal recessive MyD88 deficiency suffered from life-threatening, often recurrent pyogenic bacterial infections, including invasive pneumococcal disease. However, these patients were otherwise healthy, with normal resistance to other microbes. Their clinical status improved with age, but not due to any cellular leakiness in MyD88 deficiency. The MyD88-dependent TLRs and IL-1Rs are therefore essential for protective immunity to a small number of pyogenic bacteria, but redundant for host defense to most natural infections.