Proliferation and rooting of wild cherry: The influence of cytokinin and auxin types and their concentration

Determination of the most optimal type and concentration of plant growth regulators as medium constituents is one of the most important aspects of successful micro propagation, among other in vitro factors. With the aim of optimization of in vitro multiplication of wild cherry, the effect of the following cytokinins was studied: 6-benzyladenine (BAP), 2-isopentenyl adenine (2iP) and kinetin (Kin) at concentrations of 1, 2, 4 and 8 mg. l-1. Stem segments of seedlings from juvenile and adult materials were disinfected and grown on a Quoirin and Lepoivre (1977) (QL) medium without growth regulators for 4 weeks. Each material responded differently to the tested cytokinins. The use of 6-benzyladenine resulted in the highest percentage of sprouting, the development of shoots and the ratios of multiplication for two materials of Prunus avium L. In the next  experiment, seedlings from the juvenile and adult materials were grown on (MS2/5) medium in the presence of auxins indole-3-butyric acid (IBA), naphtaleneacetic acid (NAA), indole-3-acetic acid (IAA), when compared with concentrations of 0.5, 1, 2, and 4 mg. l-1. For the type of explants and its reactivity with the type and the concentration of auxin, significant differences among explants for root induction were observed. The adult material did not develop roots in any of the auxin and concentration used. In the case of the juvenile material, the IBA was distinguished from the other auxins tested and the highest induction of roots took place in 1mg. l-1. The most significant induction of cal characterizes, especially, the mediums containing the NAA followed by the IAA with concentrations of 2 and 4 mg. l-1, respectively, which block the emergence of the roots partly and decreases the rate of rooting thereafter. The highest average number of roots and the highest average length of roots were obtained with the IBA with 1 mg. l-1.Key words: Wild cherry tree, proliferation, cytokinins, rooting, auxins

Isolation of an extremely halophilic arhaeon Natrialba sp. C21 able to degrade aromatic compounds and to produce stable biosurfactant at high salinity

Natrialba sp. strain C21 was isolated from oil contaminated saline water in Ain Salah (Algeria) and has exhibited a good potential for degrading phenol (3 % v/v), naphthalene (3 % v/v), and pyrene (3 % v/v) at high salinity with high growth, enzymatic activity and biosurfactant production. Successful metabolism of aromatic hydrocarbon compounds of the strain Natrialba sp. C21 appears to require the ortho-cleavage pathway. Indeed, assays of the key enzymes involved in the ring cleavage of catechol 1, 2-dioxygenase indicated that degradation of the phenol, naphthalene and pyrene by strain Natrialba sp. C21 was via the ortho-cleavage pathway. Cells grown on aromatic hydrocarbons displayed greater ortho-activities mainly towards catechol, while the meta-activity was very low. Besides, biosurfactants derived from the strain C21 were capable of effectively emulsifying both aromatic and aliphatic hydrocarbons and seem to be particularly promising since they have particular adaptations like the increased stability at high temperature and salinity conditions. This study clearly demonstrates for the first time that strain belonging to the genera Natrialba is able to grow at 25 % (w/v) NaCl, utilizing phenol, naphthalene, and pyrene as the sole carbon sources. The results suggest that the isolated halophilic archaeon could be a good candidate for the remediation process in extreme environments polluted by aromatic hydrocarbons. Moreover, the produced biosurfactant offers a multitude of interesting potential applications in various fields of biotechnology. © 2015 Springer Japa

EXTREMELY HALOPHILIC ARCHAEA FROM ALGERIAN SALT LAKES: ISOLATION, PHYLOGENETIC IDENTIFICATION AND BIOPROSPECTION OF HYDROLYTIC ENZYMES

International audienc

Isolation and characterization of halophilic archaea able to produce biosurfactants

Halotolerants microorganisms able to live in saline environments, offer a multitude of actual or potential applications in various fields of biotechnology. This is why some strains of Halobacteria from an Algerian culture collection were screened for biosurfactant production in a standard medium using the qualitative drop-collapse test and emulsification activity assay. Five of the Halobacteria strains reduced the growth medium surface tension below 40mNm-1 and two of them exhibited high emulsion-stabilising capacity. Diesel oil-in-water emulsions were stabilized over a broad range of conditions, from pH 2 to 11, with up to 35% sodium chloride or up to 25% ethanol in the aqueous phase. Emulsions were stable to three cycles of freezing and thawing. The components of the biosurfactant were determined; it contains sugar, protein and lipid. The two Halobacteria strains with enhanced biosurfactants producers designed strain A21 and strain D21 were selected to identify by phenotypic, biochemical characteristics and by partial 16S rRNA gene sequencing. The strains have Mg2+and salt growth requirements are always above 15% (w/v) salts with an optimal concentration of 15% to 20%. Analyses of partial 16S rRNA gene sequences of the two strains suggested that they were halophiles belonging to genera of the family Halobacteriaceae, Halovivax (strain A21) and Haloarcula (strain D21). To our knowledge, this a first report of biosurfactant production at such a high salt concentratio

Physicochemical Profile of Essential Oil of Daucus carota

Essential oils have a significant antimicrobial activity. These oils can successfully replace the antibiotics. So, the microorganisms show their inefficiencies resistant for the antibiotics. For this reason, we study the physicochemical analysis and antimicrobial activity of the essential oil of Daucus carota. The extraction is done by steam distillation of water which brought us a very significant return of 4.65%. The analysis of the essential oil is performed by GC / MS and has allowed us to identify 32 compounds in the oil of D. carota flowering tops of Bouira. Three of which are in the majority are the α-Pinene (22.3%), the carotol (21.7%) and the limonene (15.8%

Bacterial community issued from a Chlorophytum plant-microbial fuel cell for electricity generation

Some microorganisms, particularly bacteria, can adhere to conductive surfaces and grow as an electroactive biofilm, on which they communicate electrochemically and generate electricity. Here, a bacterial community isolated from anodic electroactive biofilms of a Microbial Fuel Cell planted with Chlorophytum comosom is studied. Seventeen different bacterial strains were isolated from electroactive biofilms and were identified using the 16S rRNA marker gene. The strains were affiliated to 8 bacteria families and 8 genera (Aeromonas, Enterobacter, Alcaligenes, Pseudomonas, Clostridium, Paraclostridium, Enterococcus and Kurthia spp.). After that, it was demonstrated using electrochemical methods, principally imposed potential chronoamperometry under +0.155 mV/SCE, that the consortium constituted of 17 strains was able to exchange electrons with conductive materials. A maximum current density of 345 µA/cm2 was revealed at 48h of the study, using acetate as the sole carbon source and without any additional external mediator.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Caldicoprobacter algeriensis sp nov a new thermophilic anaerobic, xylanolytic bacterium isolated from an Algerian hot spring

A thermophilic anaerobic bacterium (strain TH7C1(T)) was isolated from the hydrothermal hot spring of Guelma in the northeast of Algeria. Strain TH7C1(T) stained Gram-positive, was a non-motile rod appearing singly, in pairs, or as long chains (0.7-1 x 2-6 mu m(2)). Spores were never observed. It grew at temperatures between 55 and 75A degrees C (optimum 65A degrees C) and at pH between 6.2 and 8.3 (optimum 6.9). It did not require NaCl for growth, but tolerated it up to 5 g l(-1). Strain TH7C1(T) is an obligatory heterotroph fermenting sugars including glucose, galactose, lactose, raffinose, fructose, ribose, xylose, arabinose, maltose, mannitol, cellobiose, mannose, melibiose, saccharose, but also xylan, and pyruvate. Fermentation of sugars only occurred in the presence of yeast extract (0.1%). The end-products from glucose fermentation were acetate, lactate, ethanol, CO2, and H-2. Nitrate, nitrite, thiosulfate, elemental sulfur, sulfate, and sulfite were not used as electron acceptors. The G+C content of the genomic DNA was 44.7 mol% (HPLC techniques). Phylogenetic analysis of the small-subunit ribosomal RNA (rRNA) gene sequence indicated that strain TH7C1(T) was affiliated to Firmicutes, order Clostridiales, family Caldicoprobacteraceae, with Caldicoprobacter oshimai (98.5%) being its closest relative. Based on phenotypic, phylogenetic, and genetic characteristics, strain TH7C1(T) is proposed as a novel species of genus Caldicoprobacter, Caldicoprobacter algeriensis, sp. nov. (strain TH7C1(T) = DSM 22661(T) = JCM 16184(T))

Characterization of a purified thermostable xylanase from Caldicoprobacter algeriensis sp. nov. strain TH7C1(T)

The present study investigates the purification and biochemical characterization of an extracellular thermostable xylanase (called XYN35) from Caldicoprobacter algeriensis sp. nov., strain TH7C1(T), a thermophilic, anaerobic strain isolated from the hydrothermal hot spring of Guelma (Algeria). The maximum xylanase activity recorded after 24 h of incubation at 70 degrees C and in an optimized medium containing 10 g/L mix birchwood-and oats spelt-xylan was 250 U/mL. The pure protein was obtained after heat treatment (1 h at 70 degrees C), followed by sequential column chromatographies on Sephacryl S-200 gel filtration and Mono-S Sepharose anion-exchange. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis indicated that the purified enzyme is a monomer with a molecular mass of 35,075.10 Da. The results from amino-acid sequence analysis revealed high homology between the 21 NH2-terminal residues of XYN35 and those of bacterial xylanases. The enzyme showed optimum activity at pH 11 and 70 degrees C. While XYN35 was activated by Ca2+, Mn2+, and Mg2+, it was completely inhibited by Hg2+ and Cd2+. The xylanase showed higher specific activity on soluble oat-spelt xylan, followed by beechwood xylan. This enzyme was also noted to obey the Michaelis-Menten kinetics, with Km and kcat values on oat-spelt xylan being 1.33 mg/mL and 400 min(-1), respectively. Thin-layer chromatography soluble oat-spelt xylan (TLC) analysis showed that the final hydrolyzed products of the enzyme from birchwood xylan were xylose, xylobiose, and xylotriose. Taken together, the results indicated that the XYN35 enzyme has a number of attractive biochemical properties that make it a potential promising candidate for future application in the pulp bleaching industry