Search results for "Biotechnology"
showing 10 items of 5678 documents
Barcoding of parasitoid wasps (Braconidae and Chalcidoidea) associated with wild and cultivated olives in the Western Cape of South Africa
2019
Wild and cultivated olives harbor and share a diversity of insects, some of which are considered agricultural pests, such as the olive fruit fly. The assemblage of olive-associated parasitoids and seed wasps is rich and specialized in sub-Saharan Africa, with native species possibly coevolving with their hosts. Although historical entomological surveys reported on the diversity of olive wasp species in the Western Cape Province of South Africa, no comprehensive study has been performed in the region in the molecular era. In this study, a dual approach combining morphological and DNA-based methods was used for the identification of adult specimens reared from olive fruits. Four species of B…
Microalgae, old sustainable food and fashion nutraceuticals.
2017
8 p.-1 fig.
Synthesis of Isomaltooligosaccharides by Saccharomyces cerevisiae Cells Expressing Aspergillus niger α‑Glucosidase
2017
The α-glucosidase encoded by the aglA gene of Aspergillus niger is a secreted enzyme belonging to family 31 of glycoside hydrolases. This enzyme has a retaining mechanism of action and displays transglycosylating activity that makes it amenable to be used for the synthesis of isomaltooligosaccharides (IMOs). We have expressed the aglA gene in Saccharomyces cerevisiae under control of a galactose-inducible promoter. Recombinant yeast cells expressing the aglA gene produced extracellular α-glucosidase activity about half of which appeared cell bound whereas the other half was released into the culture medium. With maltose as the substrate, panose is the main transglycosylation product after 8…
Flashing light emitting diodes (LEDs) induce proteins, polyunsaturated fatty acids and pigments in three microalgae
2020
As the periodic emission of light pulses by light emitting diodes (LEDs) is known to stimulate growth or induce high value biocompounds in microalgae, this flashing light regime was tested on growth and biochemical composition of the microalgae Nannochloropsis gaditana, Koliella antarctica and Tetraselmis chui. At low flashing light frequencies (e.g., 5 and 50 Hz, Duty cycle = 0.05), a strain-dependent growth inhibition and an accumulation of protein, polyunsaturated fatty acids, chlorophyll or carotenoids (lutein, β-carotene, violaxanthin and neoxanthin) was observed. In addition, a 4-day application of low-frequency flashing light to concentrated cultures increased productivities of eicos…
Plant growth promotion, metabolite production and metal tolerance of dark septate endophytes isolated from metal-polluted poplar phytomanagement sites
2016
Numerous studies address the distribution and the diversity of dark septate endophytes (DSEs) in the literature, but little is known about their ecological role and their effect on host plants, especially in metal-polluted soils. Seven DSE strains belonging to Cadophora, Leptodontidium, Phialophora and Phialocephala were isolated from roots of poplar trees from metal-polluted sites. All strains developed on a wide range of carbohydrates, including cell-wall-related compounds. The strains evenly colonized birch, eucalyptus and ryegrass roots in re-synthesis experiments. Root and shoot growth promotion was observed and was both plant and strain dependent. Two Phialophora and Leptodontidium st…
Mechanisms of Resistance to Insecticidal Proteins from Bacillus thuringiensis
2021
Insecticidal proteins from the bacterium Bacillus thuringiensis ( Bt) are used in sprayable formulations or produced in transgenic crops as the most successful alternatives to synthetic pesticides. The most relevant threat to sustainability of Bt insecticidal proteins (toxins) is the evolution of resistance in target pests. To date, high-level resistance to Bt sprays has been limited to one species in the field and another in commercial greenhouses. In contrast, there are currently seven lepidopteran and one coleopteran species that have evolved practical resistance to transgenic plants producing insecticidal Bt proteins. In this article, we present a review of the current knowledge on mec…
Prebiotic effect of xylooligosaccharides produced from birchwood xylan by a novel fungal GH11 xylanase.
2017
34 p.-4 fig.-1 tab.
Molecule structural factors influencing the loading of flavoring compounds in a natural-preformed capsule: Yeast cells
2016
International audience; Yeast cells are efficient microcapsules for the encapsulation of flavoring compounds. However, as they are preformed capsules, they have to be loaded with the active. Encapsulation efficiency is to a certain level correlated with LogP. In this study, the effect of structural factors on the encapsulation of amphiphilic flavors was investigated. Homological series of carboxylic acids, ethyl esters, lactones, alcohols and ketones were encapsulated into the yeast Yarrowia lipolytica. Although, in a single homological series, the length of the molecule and thus the LogP were correlated with encapsulation efficiency (EY%), big differences were observable between series. Fo…
Enhancing heterologous protein expression and secretion in HEK293 cells by means of combination of CMV promoter and IFNα2 signal peptide
2016
Efficient production and secretion of recombinant proteins in mammalian cell lines relies in a combination of genetic, metabolic and culture strategy factors. The present work assesses the influence of two key genetic components of expression vectors (promoter and signal peptide) on protein production and secretion effciency in HEK293 cells expressing eGFP as a reporter protein. Firstly, the strength of 3 different promoters was evaluated using transient expression methods. Flow cytometry analysis revealed that the highest level of intracellular protein expression was found when eGFP was under the control of CMV promoter, being 3-times higher in comparison to the rest of the promoters teste…
Selection of indigenous yeast strains for the production of sparkling wines from native Apulian grape varieties.
2018
We report the first polyphasic characterization of native Saccharomyces cerevisiae in order to select candidate strains for the design of starter cultures tailored for Apulian sparkling wines obtained from local grape variety. In addition, it is the first survey in our region that propose the selection of autochthonous starter cultures for sparkling wine i) including a preliminary tailored genotypic and technological screening, and ii) monitoring analytical contribution during secondary fermentation in terms of volatile compounds (VOCs). Furthermore, we exploit the potential contribute of autochthonous cultures throughout the productive chain, including the possible improvement of base wine…