Responses of Arabidopsis thaliana to bicarbonate-induced iron deficiency

Morpho-physiological and biochemical responses of Arabidopsis thaliana (accession N1438) to bicarbonate-induced iron deficiency were investigated. Plants were grown in cabinet under controlled conditions, in a nutrient solution containing 5 μM Fe, added or not with 10 mM NaHCO₃. After 30 days, bicarbonate-treated plants displayed significantly lower biomass, leaf number and leaf surface area as compared to control plants, and slight yellowing of their younger leaves was observed. Potassium (K⁺) content was not modified by bicarbonate treatment in roots, whereas it was significantly diminished in shoots. Their content in ferrous iron (Fe²⁺) and in leaf total chlorophylls was noticeably lower than in control plants. Root Fe(III)-chelate reductase and phosphoenolpyruvate carboxylase (PEPC) activities were significantly enhanced, but leaf ribulose 1.5-bisphosphate carboxylase (Rubisco) activity was decreased.     

Spasmolytic and anti-inflammatory effects of constituents from Hertia cheirifolia

A sesquiterpenoid Bakkenolide (1), and two steroids, (3β, 22E)-Stigmasta-5, 22-diène-3-ol (Stigmasterol) (2) and stigmasterol 3β-glucoside (3), isolated from the Hertia cheirifolia (L.) chloroform extract, were evaluated respectively for their spasmolytic and anti-inflammatory activities. We note that these natural products were isolated and purified for the first time from the specie Hertia cheirifolia. Their structures have been established by spectroscopy (1 and 2D NMR experiences) and mass spectrometry. Chloroform-, ethyl acetate- and methanol-extracts were also tested for their spasmolytic and anti-inflammatory activities. Spasmolytic and anti-inflammatory screening were based respectively on the contractile response effects on rat isolated smooth muscles and on the dose-related carrageenan induced paw edema in rats. screening of the crude extracts showed spasmolytic and anti-inflammatory positive results. The antispasmodic effect of Bakkenolide was found in the same range as that of Alverine, a standard musculotropic spasmolytic agent.     

Malachite green decolourization and detoxification by the laccase from a newly isolated strain of Trametes sp.

The decolourization and detoxification of the triarylmethane dye Malachite green (MG) by laccase from Trametes sp. were investigated. The laccase decolorized efficiently the dye down to 97% of 50 mg L^?1 initial concentration of MG when only 0.1 U mL^?1 of laccase was used in the reaction mixture. The effects of different physicochemical parameters were tested and optimal decolourization rates occurred at pH 6 and at temperatures between 50 and 60 °C. Decolourization of MG occurred in the presence of metal ions which could be found in textile industry effluent. 1-hydroxybenzotriazole (HBT) affected positively the decolourization of MG. The presence of some phenolic compounds namely ferulic, coumaric, gallic, and tannic acids was found to be inhibiting for the decolourization at a concentration of 10 mM.The effect of laccase inhibitors in the decolourization of MG was tested with l-cysteine, and ethylene diamine tetra-acetic acid (EDTA) at concentrations of 0.1, 1 and 10 mM. It was demonstrated that l-cysteine and EDTA inhibited the decolourization starting from 1 mM concentration. However, for NaCl a concentration of 100 mM was needed for the inhibition of laccase. The decolourization of MG resulted in the removal of its toxicity against Phanerochaete chrysosporium.The stability of the laccase toward temperature and HBT free radicals was also assessed during MG decolourization. It was shown that laccase was stable at 50 °C but in the presence of the laccase mediator HBT, the stability of the enzyme was severely affected resulting in a loss of 50% of the activity after 3 h incubation.     

Reproductive performance of the wild white-lipped peccary (<Emphasis Type="Italic">Tayassu pecari</Emphasis>) female in the Peruvian Amazon

The ability of any species to support high hunting pressures depends on its reproductive efficiency. Based on the gross anatomic examination of 208 adult female reproductive tracts, we characterised the reproductive biology of the wild white-lipped peccary in the northeastern Peruvian Amazon. White-lipped peccary apparently bred year round in the northeastern Peruvian Amazon, and the number of pregnant females was 80 (38.4%). Mean ovulation rate was 2.09 ± 0.47 CLs, and litter size was 1.60 ± 0.49 embryos or foetuses per pregnant female. A phenomenon of embryo migration was observed in the 27.5% of pregnant females. Estimations suggest 0.89 births per year and a yearly reproductive production of 1.42 piglets per pregnant female. Females in the late pregnancy stage showed a higher hunting vulnerability that could be an important restrictive factor for the reproductive efficiency of the wild white-lipped peccary populations in the Peruvian Amazon.     

Genome scan to assess the respective role of host-plant and environmental constraints on the adaptation of a widespread insect

Background  

The evolutionary success of phytophagous insects could result from their adaptation to different host-plants. Alternatively, the diversification of widespread species might be driven by adaptation along environmental gradients. To disentangle the respective roles of host-plant versus abiotic environmental variables acting on the genome of an oligophagous insect, we performed a genome scan using 83 unlinked AFLP markers on larvae of the large pine weevil collected on two host-plants (pine and spruce) in four forestry regions across Europe.     

Gene expression following induction of regeneration in <Emphasis Type="Italic">Drosophila</Emphasis> wing imaginal discs. Expression profile of regenerating wing discs

Background  

Regeneration is the ability of an organism to rebuild a body part that has been damaged or amputated, and can be studied at the molecular level using model organisms. Drosophila imaginal discs, which are the larval primordia of adult cuticular structures, are capable of undergoing regenerative growth after transplantation and in vivo culture into the adult abdomen.