Role of Bacillus cereus in Improving the Growth and Phytoextractability of Brassica nigra (L.) K. Koch in Chromium Contaminated Soil

Plant growth-promoting rhizobacteria (PGPR) mediate heavy metal tolerance and improve phytoextraction potential in plants. The present research was conducted to find the potential of bacterial strains in improving the growth and phytoextraction abilities of Brassica nigra (L.) K. Koch. in chromium contaminated soil. In this study, a total of 15 bacterial strains were isolated from heavy metal polluted soil and were screened for their heavy metal tolerance and plant growth promotion potential. The most efficient strain was identified by 16S rRNA gene sequencing and was identified as Bacillus cereus. The isolate also showed the potential to solubilize phosphate and synthesize siderophore, phytohormones (indole acetic acid, cytokinin, and abscisic acid), and osmolyte (proline and sugar) in chromium (Cr⁺³) supplemented medium. The results of the present study showed that chromium stress has negative effects on seed germination and plant growth in B. nigra while inoculation of B. cereus improved plant growth and reduced chromium toxicity. The increase in seed germination percentage, shoot length, and root length was 28.07%, 35.86%, 19.11% while the fresh and dry biomass of the plant increased by 48.00% and 62.16%, respectively, as compared to the uninoculated/control plants. The photosynthetic pigments were also improved by bacterial inoculation as compared to untreated stress-exposed plants, i.e., increase in chlorophyll a, chlorophyll b, chlorophyll a + b, and carotenoid was d 25.94%, 10.65%, 20.35%, and 44.30%, respectively. Bacterial inoculation also resulted in osmotic adjustment (proline 8.76% and sugar 28.71%) and maintained the membrane stability (51.39%) which was also indicated by reduced malondialdehyde content (59.53% decrease). The antioxidant enzyme activities were also improved to 35.90% (superoxide dismutase), 59.61% (peroxide), and 33.33% (catalase) in inoculated stress-exposed plants as compared to the control plants. B. cereus inoculation also improved the uptake, bioaccumulation, and translocation of Cr in the plant. Data showed that B. cereus also increased Cr content in the root (2.71-fold) and shoot (4.01-fold), its bioaccumulation (2.71-fold in root and 4.03-fold in the shoot) and translocation (40%) was also high in B. nigra. The data revealed that B. cereus is a multifarious PGPR that efficiently tolerates heavy metal ions (Cr⁺³) and it can be used to enhance the growth and phytoextraction potential of B. nigra in heavy metal contaminated soil.     

Measuring the fundamental frequency and the harmonic properties of the wingbeat of a large number of mosquitoes in flight using 2D optoacoustic sensors

Mosquito flight tones occur during locomotion and courtship and are mostly analyzed using microphones. The use of microphones is impractical for analyzing the wingbeat of non-tethered insects especially if one is interested in studying the frequency content of wingbeats of a large number of insects. In this study we present a practical setting based on a novel 2D optical sensor that we embed inside insectary cages to record the wingbeats of three mosquito species belonging to three different genera, namely Culex pipiens molestus, Anopheles gambiae and Aedes albopictus. We show that this setting allows to automatically create distributions of parameters related to wingbeat frequency and harmonic properties derived from many non-tethered wingbeats and therefore characterize the wingbeat properties of a whole species with increased confidence. Implications for potential applications are discussed.     

Analyse a posteriori d'erreur par reconstruction pour un modèle d'écoulement dans un milieu poreux fracturé

We present in this note a posteriori error estimates based on the postprocessing technique for the reduced model of flow in fractured porous media, introduced and analysed by V. Martin, J. Jaffré, and J. Roberts. This model is approximated by the Raviart–Thomas finite elements of lowest order. In this type of approximation, the velocity is well approximated. A postprocessing of the pressure appears to be necessary since it does not belong to $H_0^1(\mathrm{\Omega })$. We give an upper bound for the error in the energy norm, with some indicators that are expressed in terms of the reconstruction of the pressure. Numerical results show that all indicators converge to zero when the mesh size goes to zero, with the same speed as the error. One of these indicators can be interpreted as both a discretization indicator and an indicator of the reduced model validity.     

1,2:5,6‐Di‐O‐Cyclohexylidene‐d‐Mannitol and Its Bis(Trimethylsilyl) Ether in the Dithiophosphorylation Reactions

The reaction of 2,4‐diaryl 1,3,2,4‐dithiadiphosphetane‐2,4‐disulfide with diketonide of d ‐mannitol has been found to give optically active bisaryldithiophosphonic acids transformed into the corresponding diammonium salts by the treatment of n‐hexadecylamine. O,O‐Bis(trimethylsilyl) ether of d ‐mannitol ketonide reacts with 2,4‐diaryl 1,3,2,4‐dithiadiphosphetane‐2,4‐disulfide to form chiral S,S‐disilylbisaryldithiophosphonate. Diammonium bisaryldithiophosphonate possesses antibacterial activity against Staphylococcus aureus ATCC 6538‐P.     

Enzyme‐Catalyzed Crosslinking in a Partly Frozen State: A New Way to Produce Supermacroporous Protein Structures

In this study a new way to produce supermacroporous protein structures was investigated. Enzyme‐mediated crosslinking of gelatin or casein was performed in a partly frozen state, which yielded stable, protein‐based cryogels. The reaction kinetics for the formation of cryogels were found to be fairly slow, most likely due to the low temperature (?12 °C) used or due to an increased viscosity owing to the cryo‐concentration taking place. The produced cryogels were characterized with regards to their physical properties and in vitro degradation. Furthermore, cryogels produced from gelatin and casein were evaluated as potential scaffolds by fibroblast cultivation to confirm their in vitro biocompatibility. Gelatin‐ and casein‐based scaffolds both supported cell proliferation and migration through the scaffold.