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.     

Shear wave induced resonance elastography of soft heterogeneous media

In the context of ultrasound dynamic elastography imaging and characterization of venous thrombosis, we propose a method to induce mechanical resonance of confined soft heterogeneities embedded in homogenous media. Resonances are produced by the interaction of horizontally polarized shear (SH) waves with the mechanical heterogeneity. Due to such resonance phenomenon, which amplifies displacements up to 10 times compared to non-resonant condition, displacement images of the underlying structures are greatly contrasted allowing direct segmentation of the heterogeneity and a more precise measurement of displacements since the signal-to-noise ratio is enhanced. Coupled to an analytical model of wave scattering, the feasibility of shear wave induced resonance (SWIR) elastography to characterize the viscoelasticity of a mimicked venous thrombosis is demonstrated (with a maximum variability of 3% and 11% for elasticity and viscosity, respectively). More generally, the proposed method has the potential to characterize the viscoelastic properties of a variety of soft biological and industrial materials.     

Proximate causes and consequences of intergenerational influences of salient sensory experience

Salient sensory environments experienced by a parental generation can exert intergenerational influences on offspring. While these data provide an exciting new perspective on biological inheritance, questions remain about causes and consequences of intergenerational influences of salient sensory experience. We previously showed that exposing male mice to a salient olfactory experience, like olfactory fear conditioning, resulted in offspring demonstrating a sensitivity to the odor used to condition the paternal generation and possessing enhanced neuroanatomical representation for that odor. In this study, we first injected RNA extracted from sperm of male mice that underwent olfactory fear conditioning into naïve single‐cell zygotes and found that adults that developed from these embryos had increased sensitivity and enhanced neuroanatomical representation for the odor (Odor A) with which the paternal male had been conditioned. Next, we found that female, but not male offspring sired by males conditioned with Odor A show enhanced consolidation of a weak single‐trial Odor A + shock fear conditioning protocol. Our data provide evidence that RNA found in the paternal germline after exposure to salient sensory experiences can contribute to intergenerational influences of such experiences, and that such intergenerational influences confer an element of adaptation to the offspring. In so doing, our study of intergenerational influences of parental sensory experience adds to existing literature on intergenerational influences of parental exposures to stress and dietary manipulations and suggests that some causes (sperm RNA) and consequences (behavioral flexibility) of intergenerational influences of parental experiences may be conserved across a variety of parental experiences.     

Hmgcr in the corpus allatum controls sexual dimorphism of locomotor activity and body size via the insulin pathway in Drosophila

The insulin signaling pathway has been implicated in several physiological and developmental processes. In mammals, it controls expression of 3-Hydroxy-3-Methylglutaryl CoA Reductase (HMGCR), a key enzyme in cholesterol biosynthesis. In insects, which can not synthesize cholesterol de novo, the HMGCR is implicated in the biosynthesis of juvenile hormone (JH). However, the link between the insulin pathway and JH has not been established. In Drosophila, mutations in the insulin receptor (InR) decrease the rate of JH synthesis. It is also known that both the insulin pathway and JH play a role in the control of sexual dimorphism in locomotor activity. In studies here, to demonstrate that the insulin pathway and HMGCR are functionally linked in Drosophila, we first show that hmgcr mutation also disrupts the sexual dimorphism. Similarly to the InR, HMGCR is expressed in the corpus allatum (ca), which is the gland where JH biosynthesis occurs. Two p[hmgcr-GAL4] lines were therefore generated where RNAi was targeted specifically against the HMGCR or the InR in the ca. We found that RNAi-HMGCR blocked HMGCR expression, while the RNAi-InR blocked both InR and HMGCR expression. Each RNAi caused disruption of sexual dimorphism and produced dwarf flies at specific rearing temperatures. These results provide evidence: (i) that HMGCR expression is controlled by the InR and (ii) that InR and HMGCR specifically in the ca, are involved in the control of body size and sexual dimorphism of locomotor activity.     

Epidemiology and Genetic Characterization of Measles Strains in Senegal, 2004-2013

BackgroundIn Senegal, with the variable routine vaccination coverage, the risk for illness and death from measles still exists as evidenced by the measles epidemic episode in 2009. Since 2002 a laboratory-based surveillance system of measles was established by the Ministry of Health and the Institut Pasteur de Dakar. The present study analysed the data collected over the 10 years inclusive between 2004-2013 in order to define a measles epidemiological profile in Senegal, and we carried out a phylogenetic analysis of measles virus circulating in Senegal over the period 2009-2012.ConclusionImprovements in the measles surveillance in Senegal are required and the introduction of oral fluid and FTA cards as an alternative to transportation of sera should be investigated to improve surveillance. The introduction of a national vaccine database including number of doses of measles-containing vaccine will greatly improve efforts to interrupt and ultimately eliminate measles virus transmission in Senegal.     

β-glucosidase from <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis>: a new and efficient purification procedure and use as a suitable marker in immuno-enzymatic assay

The β-glucosidase enzyme β-glu2 isolated from Sclerotinia sclerotiorum was purified and used as tracer in enzyme linked immunosorbent assay. A novel purification procedure of the protein was developed that consists of ammonium sulphate precipitation, gel filtration on Sephacryl S-200-HR column, ion exchange chromatography on DEAE-Toyopearl and polybuffer exchanger PBE 94 TM chromatofocusing. The pI value was 4.45. K _m and V _max values for the enzyme towards p-nitrophenyl-β-D-glucopyranoside were respectively 0.45 mM and 0.2 U/mL. Thermal stability showed that β-glu2 has a half-life of 85 min at 55 °C and of 25 min at 65 °C. β-glu2 was conjugated to goat anti-rabbit antibodies with glutaraldehyde as cross linking agent according to the one-step method. Conjugates were purified by HPLC gel filtration on TSK 2000. Enzymatic and immunological activities of the β-glucosidase conjugate component were tested by the ELISA method.     

Effects of N and P supply on phytoplankton in Bizerte Lagoon (western Mediterranean)

Enriched bottle experiments were conducted in situ during winter (January and February) and summer (July and August) 2001 to examine the effects of nutrient enrichments (+ N, + P and + NP) on phytoplankton in Bizerte Lagoon, Tunisia. Chlorophyll a (Chl a), ranging from 3.05 μg L⁻¹ in winter to 4.52 μg L⁻¹ in summer, was dominated by the small size-faction (<5 μm) during both seasons. However, the contribution of the large size-fraction (5-200 μm) to Chl a increased from winter (26%) to summer (37%). Similarly, the carbon biomass of the 5-200 μm algae increased during the July/August period that was characterised by the high proliferation of several diatom taxa. In winter, N was the limiting element for phytoplankton growth. Its addition alone (+ N) or with P (+ NP) increased both the <5 μm and 5-200 μm Chl a concentrations. There was no change in the phytoplankton size structure, with the small cells dominating the final algal biomass in all treatments after 5 days. In summer, N and P limited the phytoplankton, but small and large algae exhibited diverse responses to different nutrient enrichments: addition of P increased the Chl a only in the 5-200 μm fraction, the + N treatment enhanced both size classes, and the NP fertilisation mostly stimulated the biomass of large cells. Consequently, the N and P addition in summer was followed by a significant change in the phytoplankton size structure, since both size-fractions contributed equally to the final Chl a biomass. Within the 5-200 μm algal community, various taxa had diverse responses to the nutrient supply during both seasons, leading to a change in the final community composition. The autotrophic flagellates appeared to grow well under N-deficient conditions. In contrast, diatom growth and biomass were mostly stimulated by the N enrichment while dinoflagellates exhibited the highest increase in their growth and biomass with P fertilisation. Our results suggest that the increasing anthropogenic supply of nutrients in the lagoon may influence algal dynamics as well as productivity in different ways depending on the nutrient composition.     

Seasonal phytoplankton responses to N:Si:P enrichment ratio in the Bizerte Lagoon (southwestern Mediterranean)

This study investigated the role of N, P and Si enrichments on phytoplankton in the Bizerte Lagoon (southwestern Mediterranean Sea, Tunisia) during March, June, August, October and December 2004. Polycarbonate bottles were enriched with different nutrients according to four treatments N:Si:P ratios [+NSi/-P (40:40:1), +P/-NSi (20:20:2,5), +NP/-Si (16:0:1) and +Si/-NP (16:32:1)] and incubated in situ during six days. Chl a and carbon biomass of phytoplankton varied significantly during the course of months, with the highest levels recorded in summer (4-4.4 microg Chl a L(-1) or 1126-1721 microg C L(-1)). Dinoflagellates dominated the initial phytoplankton communities, except in August, when diatoms represented a high fraction of microalgae (48%). Enrichment experiments induced significant increases in Chl a and in the final phytoplankton carbon biomasses. In summer (June/August), Si was the main limiting element for phytoplankton. Diatoms strongly responded to +Si/-NP and +NSi/-P enrichments and dominated the final phytoplankton communities (52-61%) in both treatments. Si played the most important role in the growth and development of diatoms. The biomasses and growth rates of dinoflagellates were significantly stimulated by +P/-NSi and +NP/-Si enrichments. After 6 days, dinoflagellates represented more than 70% of the total phytoplankton biomass in samples subjected to these treatments. Moreover, the addition of +P/-NSi increased the biomasses of several dinoflagellates. This suggests that dinoflagellates were mostly controlled by P availability. Unlike diatoms and dinoflagellates, flagellates showed weak responses to nutrient treatments during only some months of the year. The results showed that phytoplankton dynamics in the lagoon were influenced by nutrients in different manners.