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Open access

Eduardo Berenguer, María-Teresa Solís, Yolanda Pérez-Pérez and Pilar S. Testillano

Abstract

Microspore embryogenesis is a model system of plant cell reprogramming, totipotency acquisition, stress response and embryogenesis initiation. This in vitro system constitutes an important biotechnological tool for haploid and doubled-haploid plant production, very useful for crop breeding. In this process, microspores (cells that produce pollen grains in planta) are reprogrammed toward embryogenesis by specific stress treatment, but many microspores die after the stress. The occurrence of cell death is a serious limiting problem that greatly reduces microspore embryogenesis yield. In animals, increasing evidence has revealed caspase proteolytic activities as essential executioners of programmed cell death (PCD) processes, however, less is known in plants. Although plant genomes do not contain caspase homologues, caspase-like proteolytic activities have been detected in many plant PCD processes. In the present study, we have analysed caspase 3-like activity and its involvement in stress-induced cell death during initial stages of microspore embryogenesis of Brassica napus. After stress treatment to induce embryogenesis, isolated microspore cultures showed high levels of cell death and caspase 3-like proteolytic activity was induced. Treatments with specific inhibitor of caspase 3-like activity reduced cell death and increased embryogenesis induction efficiency. Our findings indicate the involvement of proteases with caspase 3-like activity in the initiation and/or execution of cell death at early microspore embryogenesis in B. napus, giving new insights into the pathways of stress-induced cell death in plants and opening a new way to improve in vitro embryogenesis efficiency by using chemical modulators of cell death proteases.

Open access

Arda Acemi and Fazıl Özen

Abstract

Serapias vomeracea is an economically important orchid species which is over-collected from nature, because of its glucomannan-rich tubers. Thus, optimization of in vitro culture methodology in this species is required to meet industrial needs and to secure its populations in nature. This study aimed to optimize the surface sterilization protocol for S. vomeracea seeds and to select the optimal seed germination medium by comparing the commonly used media in in vitro orchid culture. During seed surface sterilization, ethyl alcohol (EtOH) pre-treatment prior to sodium hypochlorite (NaOCl) treatment increased the disinfection success and viable seed yield when examined using the triphenyl tetrazolium chloride (TTC) seed viability test. Also, low-g force centrifugation as an additional step in the surface sterilization method separated the seeds without embryo from the viable seeds and thereby decreased potential counting errors after incubation. Comparison of media showed that solid Knudson C (KN) medium induced the highest number of germinated seeds. However, seed germination success of Lindemann (LN) and Vacin & Went (VW) media was found to be higher when the media was used in liquid form. Half-strength liquid VW was the only medium that induced higher germination success than the other full-strength media. The highest number of ungerminated seeds was found when using KN medium whereas liquid VW medium gave the lowest number. In general, protocorm formation was triggered when the media were used in liquid form. However, rhizoid elongation was suppressed in liquid media. These findings suggest that this optimized seed surface sterilization method offers a simple and effective alternative to classical methods. Additionally, solid KN medium may be considered as a cost-effective and reliable alternative to other commonly-used complex media in S. vomeracea cultures.

Open access

Khadija Ben Othmen, Walid Elfalleh, Belgacem Lachiheb and Mansour Haddad

Abstract

The Ceratonia siliqua fruits contain several substances known to have high adaptability to environmental conditions. The aim of this paper is to evaluate the changes in physicochemical properties of different Tunisian provenances of carob pulps harvested at three ripening stages. Furthermore, six provenances were investigated during the ripening process in terms of their moisture, ash, minerals, bioactive compounds, antiradical activity and sugar profile. The results demonstrated that all examined parameters are highly influenced by geographic origin. Concerning ripening impact, our data showed that water and ash content significantly decreased during the development of six provenances, as well as the bioactive and mineral contents. Thus, the total polyphenols (TP), total flavonoids (TF) and condensed tannins (CT) contents exhibited the highest levels in the unripe fruits. The antiradical activity trend was positively correlated to the behavior of the bioactive compounds content. Moreover, the sucrose, glucose and fructose were the main sugar qualified and quantified in carob pods at different ripening stages. At the maturity stage, the monosaccharide contents (glucose and fructose) were slightly reduced, while, the sucrose was rapidly accumulated. In conclusion, the ripening process diversely affected the nutritional composition and generally extended the exploitation of carob fruits. The study could provide valuable information about the suitability of carob pods at different maturity stages as potential biomaterials for nutraceutical applications.

Open access

Boda Ravi Kiran and M.N.V. Prasad

Abstract

Lead (Pb) is a major inorganic pollutant with no biological significance and has been a global concern. Phytotoxicity of lead induces toxic effects by generating reactive oxygen species (ROS), which inhibits most of the cellular processes in plants. Hydro-ponic experiments were performed with Ricinus communis to investigate the toxicity and antioxidant responses by exposing to different concentrations of lead (0, 200 and 400 µM) for 10 days. Pb stress caused a significant increase in electrolyte leakage, non-enzymatic antioxidants (phenols and flavonoids) and a decrease in the elemental profile of the plant. Histochemical visualization clearly indicates the significant increase of H2O2 production in dose-dependent manner under Pb stress. Likewise, an increase in catalase, guaiacol peroxidase and superoxide dismutase activity was also evident. Ascorbate peroxidase and MDAR, on the other hand, responded biphasically to Pb treatments showing a decrease in concentration. The decline in redox ratio GSH/GSSG was imposed by the indirect oxidative stress of Pb. Hence these findings showed the ameliorative potential of R. communis to sustain Pb toxicity under oxidative stress.

Open access

Ahmed Sameer Al-Badran and Adam Mechler

Abstract

Preventing the corrosion of iron in inaccessible structures requires a coating method that reaches all surface areas and creates a uniform protective layer. An ages old practice to protect iron artefacts is to coat them with animal fat, that is, a mixture of lipids. This “method” is accidentally ingenious: some natural phospholipids found in animal fat have the potential to form a tightly packed self-assembled monolayer on metal oxide surfaces, similar to the surfactant monolayers that have attracted increasing attention lately. Thus, the most primitive corrosion prevention method may point at a way to coat complex iron structures in an industrial environment. Here the ability of phosphatidic acid, a natural lipid, to coat and protect iron surfaces was examined. Iron coated quartz crystal microbalance (QCM) sensors were used for the experiments, to monitor the deposition of the lipid as well as the acidic corrosion (dissolution) of iron in situ, in real time. The sensors were coated by self-assembled monolayers of di-myristoyl phosphatidic acid using the liposome deposition method. In this process, 50-100 nm vesicles formed by the lipid are delivered in an aqueous solution and spontaneously coat the iron surfaces upon contact. QCM and ellipsometry measurements confirmed that continuous bilayer and monolayer surface coatings can be achieved by this method. QCM measurements also confirmed that the layers were corrosion resistant in 0.01M acetic acid solution that would dissolve the thin iron layer in minutes in the absence of the protective coating. XPS results suggested a chemisorption-based mechanism of phosphatidic acid attachment to the iron surface. Hence, liposome deposition of phosphatidic acid offers a suitable solution to coat iron surfaces in inaccessible structures in situ.

Open access

Mihaela-Doina Niculescu, Doru-Gabriel Epure, Magdalena Lasoń-Rydel, Carmen Gaidau, Mihai Gidea and Cristina Enascuta

Abstract

In the present research biocomposites based on extracts of collagen and keratin recovered from the leather industry by-products were made and the specific properties for applications in agriculture and industry were studied. To this aim, collagen and keratin have been extracted from bovine leather and sheep wool by-products and have been added and crosslinked with recognized compounds for reduced environmental impact (glycerol, vegetable tanning extract, essential oils with fungicidal properties and insecticides). The biocomposite properties were evaluated on the basis of complex analytical investigations on chemical structure, texture, contact angle, mechanical resistance, water vapor permeability and water absorption, biodegradation, germination and plant biomass growth. The biocomposites have demonstrated pelliculogenic properties and nitrogen controlled release to stimulate germination and nutrition of rape seedlings, which promotes them for agricultural applications, but also other surface properties have been identified, for industrial applications, for example in leather finishing for special destinations. Addition of odorous principles with controlled release recommends this type of biocomposites for environmentally friendly products, maintenance of cleaning, etc.

Open access

Peter M. Eze, Dominic O. Abonyi, Chika C. Abba, Peter Proksch, Festus B. C. Okoye and Charles O. Esimone

Abstract

Fungi remain a promising source of novel biologically active compounds with potentials in drug discovery and development. This study was aimed at investigating the secondary metabolites from endophytic Fusarium equiseti and Epicoccum sorghinum associated with leaves of Carica papaya collected from Agulu, Anambra State, Nigeria. Isolation of the endophytic fungi, taxonomic identification, fermentation, extraction and isolation of fungal secondary metabolites were carried out using standard procedures. Chromatographic separation and spectroscopic analyses of the fungal secondary metabolites yielded three toxigenic compounds - equisetin and its epimer 5’- epiequisetin from F. equiseti, and tenuazonic acid from E. sorghinum. These compounds are known to possess several beneficial biological properties that can be explored for pharmaceutical, agricultural or industrial purposes.

Open access

Mara Georgescu, Ștefania Mariana Raita and Dana Tăpăloagă

Abstract

Various antimicrobial solutions have been tested as additives for raw milk traditional cheeses, among which Nigella sativa cold pressed seed oil (NSSO) is recognized for its positive effect on the microbial quality of such products. The overall effect on the quality of enriched cheeses during ripening is still under extensive investigation. Three batches of traditional raw milk brined cheese were included in the current experiment: control cheese without Nigella sativa seed oil (NSSO) and cheese samples enriched with 0.2 and 1% w/w NSSO. Experimental cheese samples were analyzed in duplicates for total nitrogen content (TN), at 0, 14, 28 and 42 days of ripening, while single determinations of total nitrogen (WSN) and free amino acids (FAA) were performed at 14, 28 and 42 ripening days. The TN content revealed similar values for control cheeses and NSSO cheeses, and no significant differences were noticed within the three treatment groups (p >.05) throughout ripening. WSN values followed a significant rising shift in all cheeses during ripening, yet computing data obtained for the three considered treatments, despite an obvious higher WSN content of NSSO enriched cheeses, no statistical significance could be associated to this difference. The FAA composition of the experimental cheeses, varied quantitatively, by increasing with ripening time, but no qualitative variation was noticed during the follow-up period. The FAA composition of the did not vary significantly within treatments.

Open access

Rosa Dorta-Vásquez, Oscar Valbuena and Domenico Pavone-Maniscalco

Abstract

Paper production generates large quantities of a solid waste known as papermaking sludge (PS), which needs to be handled properly for final disposal. The high amount of this byproduct creates expensive economical costs and induces environmental and ecological risks. Therefore, it is necessary to search uses for PS, in order to reduce the negative environmental impact and to generate a more valuable byproduct. Due to the cellulolytic composition of PS, this work evaluated a solid state fermentation process using it as substrate to obtain spores of the fungus Trichoderma asperellum. Optimal conditions to obtain T. asperellum spores were: 60% water content, 3% (w/w) salts (Nutrisol P® and Nutrisol K®), inoculum concentration at 1x105 spores/g, and pasteurized or sterilized PS. Under these conditions it was possible to obtain 2.37x109 spores/g. T. asperellum spores applied directly to pepper (Capsicum anuum) seeds without PS increased significantly seedling dry mass in greenhouse assays. This work suggests an alternative, economic and abundant substrate for production of T. asperellum spores.

Open access

Benoit Fatou, Michel Salzet and Isabelle Fournier

Abstract

We previously demonstrated that remote infrared Matrix Assisted Laser Desorption Ionization technology (Spidermass) using endogenous water as matrix (or so called water assisted laser desorption/ionization) was enabling real-time in vitro and in vivo analysis of clinical pathological tissues. In the present work, Spidermass was used to biotype human pathogens either from liquid bacteria growth in time course, from petri dish or on smears. Reproducibility experiments as well as bacteria dispersion and lipids identifications with SpiderMass in MS/MS mode were undertaken. The whole of the data establish that SpiderMass instrument allows real time bacteria biotyping and can be useful in clinic for pathogen identification.