Search results for "microorganism"
showing 10 items of 449 documents
Lipid accumulation inTrichodermaspecies
1992
Two filamentous fungi, Trichoderma harzianum and Trichoderma viride, were compared for their ability to synthesize lipids on different carbon and nitrogen sources. Three culture media were selected for each strain after preliminary screening. All the test media were nitrogen-deficient (C/N = 60) so as to stimulate lipid accumulation. For both microorganisms the glucose-ammonium sulphate medium was the most conducive to lipid production: a lipid accumulation of 17% (w/w) of biomass dry weight was obtained for T. harzianum and of 32% (w/w) of biomass dry weight for T. viride. In sucrose-sodium nitrate medium T. harzianum was able to accumulate almost 25% (w/w) of its biomass in lipid form. Ho…
Activity of bacteria strains originaited from sewage sludge against some soil fungi
2004
Abstract The potential biological activity of three bacterial strains against the four phytopathogens was examined. The bacterial strains were originated from sewage sludge water extract and from the humic acid solution obtained from the sewage sludge. The fresh bacteria cultures and filtered culture broth were used. The noncoated sugar beet seeds were coated by soaking for 15 min in the liquid culture of bacteria, then they were sown in the sterilized soil inoculated by one of the following types of soil fungus: Aphanomyces cochlioides L3, Phoma betas PH8, Pythium irregulare PIR4, Rhizoctonia solani Z10-2. The test proved that Bacillus amytoliquefaciens O1 / O3 and Flaviomonas oryzihabitan…
Neo-clerodane diterpenoids from Conyza pyrrhopappa Sch.Bip. ex A.Rich
2019
Two hitherto unknown neo-clerodane-type diterpenoids along with twelve known compounds have been isolated from Conyza pyrrhopappa Sch.Bip. ex A.Rich, a medicinal plant traditionally used across tropical Africa to relieve fever. The structures of isolates have been elucidated by a combination of spectroscopic techniques. The crude extract and the isolated compounds were evaluated in the Hela-S3 cell line and in a panel of microorganisms (bacteria and fungi) at concentrations up to 50 µg/mL. The new compounds were inactive while the pentamethylated flavonoids showed low to significant activity against the cancer cell line used. However, none of the samples showed any activity against the test…
The influence of different types of fixed orthodontic appliance on the growth and adherence of microorganisms (in vitro study).
2012
Orthodontic appliances serve as different impact zones and modify microbial adherence and colonization, acting as foreign reserves and possible sources of infection. This study was conducted to investigate the effect of different types of fixed orthodontic appliances on the growth and adherence of microorganisms in oral flora which are Streptococcus mutans (S. mutans) and Candida albicans. Sixty-four of four different fixed orthodontic appliance-samples were used, divided into four groups of sixteen. Type I: Sapphire brackets- Coated wires, type II: Sapphire brackets- Stainless steel wires, type III: Stainless steel brackets- Coated wires and type IV: Stainless steel brackets- Stainless ste…
Identificación y caracterización funcional de genes PMT relacionados con la glicosilación de proteínas en el hongo patógeno de frutos cítricos Penici…
2013
En esta tesis se ha caracterizado el mecanismo de acción del péptido antifúngico PAF26 sobre S. cerevisiae como microorganismo modelo. Mediante microscopía confocal, se ha demostrado que PAF26 marcado fluorescentemente interactúa primero con las envueltas celulares, se internaliza en vacuolas y luego se libera al citoplasma coincidiendo con la muerte celular, de forma similar a lo observado en N. crassa. Se ha constatado que los dominios catiónicos e hidrofóbicos de PAF26 se requieren para su actividad, siendo el dominio catiónico necesario para su interacción y el dominio hidrofóbico para su internalización. El péptido se localizó principalmente en las vacuolas de la cepa resistente Δarg1,…
Influence of Innovative Processing on γ-Aminobutyric Acid (GABA) Contents in Plant Food Materials
2017
Over the last several decades, γ-aminobutyric acid (GABA) has attracted much attention due to its diverse physiological implications in plants, animals, and microorganisms. GABA naturally occurs in plant materials and its concentrations may vary considerably, from traces up to μmol/g (dry basis) depending on plant matrix, germination stage, and processing conditions, among other factors. However, due to its important biological activities, considerable interest has been shown by both food and pharmaceutical industries to improve its concentration in plants. Natural and conventional treatments such as mechanical and cold stimulation, anoxia, germination, enzyme treatment, adding exogenous gl…
Review on Physiological Effects of Vermicomposts on Plants
2020
Vermicompost is a type of organic fertilizer produced by earthworms and their symbiotic microorganisms. In addition to nutrient-rich organic fraction, vermicomposts also contain plant-available soluble minerals as well as substances with plant growth-regulating activity. In order to promote understanding on beneficial effects of vermicompost in different farming systems, the aim of the present review is to analyze possible mechanisms of vermicompost action on plants. After overview of plant growth-affecting activity of vermicomposts at the level of seed germination and vegetative growth, detailed analysis is dedicated to physiological effects associated with mineral nutrition: changes in bo…
Estudio de la diversidad y evaluación de las relaciones fenotipo-genotipo para la búsqueda de cepas malolácticas de Oenococcus oeni
2015
El vino es una bebida obtenida por fermentación del mosto de uva. Durante la fermentación participan las levaduras y las bacterias lácticas que son responsables de la fermentación alcohólica y maloláctica, respectivamente. La fermentación alcohólica consiste fundamentalmente en la transformación de los azúcares del mosto en etanol y CO2, mientras que la fermentación maloláctica consiste en la conversión de ácido málico, propio del mosto, en ácido láctico y CO2. De todas las especies de bacterias lácticas relacionadas con la vinificación, Oenococcus oeni es la responsable generalmente de la FML, ello se debe a que es la que mejor tolera las condiciones estresantes del vino. Por esta razón, e…
A microcosm experiment to evaluate the influence of location and quality of plant residues on residue decomposition and genetic structure of soil mic…
2007
The effects of location (soil surface vs. incorporated in soil) and nature of plant residues on degradation processes and indigenous microbial communities were studied by means of soil microcosms incubation in which the different soil zones influenced by decomposition i.e. residues, soil adjacent to residues (detritusphere) and distant soil unaffected by decomposition (bulk soil) were considered. Plant material decomposition, organic carbon assimilation by the soil microbial biomass and soil inorganic N dynamics were studied with 13 C labelled wheat straw and young rye. The genetic structure of the community in each soil zone were compared between residue locations and type by applying B- a…
ERA-experiment “space biochemistry”
1995
Abstract The general goal of the experiment was to study the response of anhydrobiotic (metabolically dormant) microorganisms (spores of Bacillus subtilis, cells of Deinococcus radiodurans, conidia of Aspergillus species) and cellular constituents (plasmid DNA, proteins, purple membranes, amino acids, urea) to the extremely dehydrating conditions of open space, in some cases in combination with irradiation by solar UV-light. Methods of investigation included viability tests, analysis of DNA damages (strand breaks, DNA-protein cross-links) and analysis of chemical effects by spectroscopic, electrophoretic and chromatographic methods. The decrease in viability of the microorganisms was as exp…