Effect of temperature on the development of Eotetranychus hirsti (Tetranychidae) on fig leaves

International audienceThe fig spider mite, Eotetranychus hirsti is one of the major pests of fig trees worldwide. The effect of temperature on the developmental time and the survival rate of E. hirsti feeding on fig leaves was determined at six constant temperatures of 15, 20, 25, 30, 32 and 35°C. The total developmental time of females (from egg to adult emergence) at the above-mentioned temperatures was 41.29, 24.15, 16.95, 12.35, 10.21 and 10.67 days, respectively. The lower, optimal and upper developmental threshold (Tmin, Topt and Tmax, respectively) and thermal constant (K) of the pest were estimated by ordinary linear and Logan 6 nonlinear models. The lower temperature threshold (Tmin) and thermal constant (K) of the immature stages were estimated to be 9.86°C and 239.48 degree-days (DD), respectively. The Topt and Tmax were estimated to be 34.30 and 35.44°C, respectively. As the temperature increased from 15 to 30°C, the survival rate of immature stages increased from 33.33 to 70.59 %, then decreased and reached 54.91 % at 35°C. Temperature-dependent development data, thermal requirements and temperature thresholds can be used to predict the occurrence, number of generations and population dynamics of E. hirsti

Microfluidic fabrication of alendronate-loaded chitosan nanoparticles for enhanced osteogenic differentiation of stem cells

Aims: In this study, we used a cross-junction microfluidic device for preparation of alendronate-loaded chitosan nanoparticles with desired characteristics to introduce a suitable element for bone tissue engineering scaffolds. Main methods: By controlling the reaction condition in microfluidic device, six types of alendronate-loaded chitosan nanoparticles were fabricated which had different physical properties. Hydrodynamic diameter of synthetized particles was evaluated by dynamic light scattering (102 to 215 nm). Nanoparticle morphology was determined by SEM and AFM images. The osteogenic effects of prepared selected nanoparticles on human adipose stem cells (hA-MSCs) were evaluated by assessment of alkaline phosphatase (ALP) activity, calcium deposition, ALP and osteopontin gene expression. Key findings: The highest loading efficiency percentage (LE) was 32.42 ± 2.02. Based on MTT assessment, two samples which had no significant cytotoxicity were chosen for further studies (particle sizes and LE were 142 ± 6.1 nm, 198 ± 16.56 nm, 16.76 ± 3.91 and 32.42 ± 2.02, respectively). In vitro release behavior of nanoparticles displayed pH responsive characteristics. Significant faster release was seen in acidic pH = 5.8 than neutral pH = 7.4. The selected nanoparticles demonstrated higher ALP activity at 14 days in comparison to selected blank sample and osteogenic differentiation media (ODM) and a downregulation at 21 days in comparison to 14 days. Calcium content assay at 21 days displayed significant differences between alendronate-loaded nanoparticles and ODM. ALP and osteopontin mRNA expression was significantly higher than the cells cultured in ODM at 14 and 21 days. Significance: We concluded that our prepared nanoparticles significantly enhanced osteogenic differentiation of hA-MSCs and can be a suitable compartment of bone tissue engineering scaffolds. © 202