Chemical Composition and Insecticidal Activity against Tribolium Castaneum of Thapsia garganica L. Seed Essential Oil

Due to the several side effects of synthetic pesticides, including environmental pollution, threats to human health, and the development of pest resistance to insecticides, the use of alternative healthy, available and efficient agents in pest management strategies is necessary. Recently, the use of essential oil obtained from aromatic plants has shown significant potential for insect pest management. For this reason, the essential oil isolated from seeds of Thapsia garganica L. was investigated for the first time for its chemical profile, and its toxicity and repellency effects against Tribolium castaneum adults. Qualitative and quantitative analyses of the chemical composition by gas chromatography coupled to mass spectrometry (GC/MS) revealed the presence of 18 organic volatiles representing 96.8 % of the total constituents. The main compounds were 1,4-dimethylazulene (51.3 %) followed by methyl palmitate (8.2 %), methyl linoleate (6.2 %) and costol (5.1 %). Concerning the repellent effect, results revealed that SEO (Seed Essential Oil) was very repellent towards T. castaneum adults, with 100 % repellency after 2 h of exposure. Furthermore, the essential oil exhibited remarkable contact toxicity against T. castaneum (93.3 % of mortality) at the concentration of 10 % (v/v). The median lethal dose (LD₅₀) of the topical application of the seed essential oil was 4.4 %. These encouraging outcomes suggested that the essential oil from T. garganica seeds could be considered a potent natural alternative to residual persistent and toxic insecticides.     

Slug Controls Stem/Progenitor Cell Growth Dynamics during Mammary Gland Morphogenesis

Background

Morphogenesis results from the coordination of distinct cell signaling pathways controlling migration, differentiation, apoptosis, and proliferation, along stem/progenitor cell dynamics. To decipher this puzzle, we focused on epithelial-mesenchymal transition (EMT) “master genes”. EMT has emerged as a unifying concept, involving cell-cell adhesion, migration and apoptotic pathways. EMT also appears to mingle with stemness. However, very little is known on the physiological role and relevance of EMT master-genes. We addressed this question during mammary morphogenesis. Recently, a link between Slug/Snai2 and stemness has been described in mammary epithelial cells, but EMT master genes actual localization, role and targets during mammary gland morphogenesis are not known and we focused on this basic question.

Methodology/Principal Findings

Using a Slug–lacZ transgenic model and immunolocalization, we located Slug in a distinct subpopulation covering about 10–20% basal cap and duct cells, mostly cycling cells, coexpressed with basal markers P-cadherin, CK5 and CD49f. During puberty, Slug-deficient mammary epithelium exhibited a delayed development after transplantation, contained less cycling cells, and overexpressed CK8/18, ER, GATA3 and BMI1 genes, linked to luminal lineage. Other EMT master genes were overexpressed, suggesting compensation mechanisms. Gain/loss-of-function in vitro experiments confirmed Slug control of mammary epithelial cell luminal differentiation and proliferation. In addition, they showed that Slug enhances specifically clonal mammosphere emergence and growth, cell motility, and represses apoptosis. Strikingly, Slug-deprived mammary epithelial cells lost their potential to generate secondary clonal mammospheres.

Conclusions/Significance

We conclude that Slug pathway controls the growth dynamics of a subpopulation of cycling progenitor basal cells during mammary morphogenesis. Overall, our data better define a key mechanism coordinating cell lineage dynamics and morphogenesis, and provide physiological relevance to broadening EMT pathways.     

Chemical Composition,Toxicity and Repellency of Inula graveolens Essential Oils from Roots and Aerial Parts against Stored-Product Beetle Tribolium castaneum (Herbst)

In this work, essential oils extracted from roots and aerial parts of Inula graveolens by hydrodistillation and their fractions obtained by chromatographic simplification were first investigated for their chemical composition by GC/MS and then evaluated for the first time for their repellency and contact toxicity properties against Tribolium castaneumadults. Twenty-eight compounds were identified in roots essential oil (REO), which accounted for 97.9 % of the total oil composition, with modhephen-8-β-ol (24.7 %), cis-arteannuic alcohol (14.8 %), neryl isovalerate (10.6 %) and thymol isobutyrate (8.5 %) as major constituents. Twenty-two compounds were found in the essential oil from aerial parts (APEO), which accounted for 93.9 % of the total oil, with borneol (28.8 %), caryophylla-4(14),8(15)-dien-6-ol (11.5 %), caryophyllene oxide (10.9 %), τ-cadinol (10.5 %) and bornyl acetate (9.4 %) as main compounds.REO and APEO displayed stronger repellency after 2 h of exposure (80.0 and 90.0 %, respectively) against T. castaneum at the concentration of 0.12 μL/cm². After fractionation, fractions R₄ and R₅ exhibited greater effects (83.3 % and 93.3 %, respectively) than the roots essential oil. Furthermore, the fractions AP₂ and AP₃ showed higher repellency (93.3 and 96.6 %, respectively) than the aerial parts oil. The LD₅₀ values of oils from roots and aerial parts topically applied were 7.44 % and 4.88 %, respectively. Results from contact toxicity assay showed that fraction R₄ was more effective than the roots oil with LD₅₀ value of 6.65 %. These results suggests that essential oils of roots and aerial parts from I. graveolens may be explored as potential natural repellent and contact insecticides against T. castaneum in stored products.     

Chemical Composition and Insecticidal Activity of Crithmum Maritimum L. Essential Oil against Stored‐Product Beetle Tribolium Castaneum

Several plant essential oils have been used against diverse insect pests since, unlike conventional pesticides, they pose almost no risk to humans and the environment. For this reason, the essential oil (EO) isolated from the fresh leaves of Crithmum maritimum L. and its fractions (F₁–F₅) obtained by chromatographic simplification were investigated for their chemical profile, as well as for their toxicity and repellency effects against Tribolium castaneum (Herbst ) adults. The analysis by GC/MS allowed the identification of 92.8–99.1 % of the compositions of the total oil (EO) and of its fractions (F₁–F₅). The EO and its fractions F₃–F₅ were characterized by the presence of a high amount of phenylpropanoids (94.4, 94.8, 93.6, and 88.7 %, respectively): in all the samples, dill apiole was the most abundant component (EO: 94.1 %, F₃: 94.6 %, F₄: 93.4 %, and F₅: 83.3 %). In addition, the repellency assay results showed that the volatile fraction F₅ and the complete EO exhibited a higher repellency towards T. castaneum (97 % and 93 %, respectively) after 2 h of exposure at the dose of 0.04 μL/cm². The median lethal dose of the topical application of the EO was 9 %. Furthermore, the fraction F₁ possessed interesting contact toxicity against T. castaneum (80 % of mortality) at the concentration of 10 %. These results suggested that the essential oil of C. maritimum leaves might be used as an alternative to synthetic insecticides in order to prevent insects from damaging the stored products.     

Isolation and characterization of non-Frankia actinobacteria from root nodules of Alnus glutinosa, Casuarina glauca and Elaeagnus angustifolia

Actinobacterial isolates randomly obtained on nitrogen-free BAP medium from surface sterilized root nodules of Alnus glutinosa, Casuarina glauca and Elaeagnus angustifolia sampled from fields were reported. They were assigned on the basis of partial 16S rRNA sequences to Micromonospora, Nocardia and Streptomyces genera. The isolates have been screened for hydrolytic activities, indole acetic acid (IAA) and siderophores production, phosphate solubilization and antagonistic activities. Results suggest putative traits as plant growth promoting bacteria proprieties of the isolates that occur in unique association in root nodules of the three analysed actinorhizal host species.