Search results for " biotechnology"
showing 10 items of 3723 documents
Ecological distribution and characterization of four collections ofBacillus thuringiensisstrains
2008
Four Collections comprising 507 strains of Bacillus thuringiensis have been analysed in this study. A different ecological origin characterizes each collection. Collection No. 1 was established from soil, dust, and grain samples from Spanish agricultural and non-cultivated soil, silos, and mills. Collection No. 2 is the result of a screening in olive-crop related environments in Spain. Collection No. 3 is made up of strains isolated from potato-growing areas in Bolivia. Collection No. 4 has been generated for this study and includes strains collected from diverse types of samples belonging to several habitats from Spain and Mexico. Crystal morphologies and cry1A and cry2 gene content were a…
Effects of ultrasound and high pressure on physicochemical properties and HMF formation in Turkish honey types
2018
Abstract In industrial production, thermal processing of honey at 50 °C commonly induces liquefaction, i.e. it reduces the crystal count and viscosity and delays any subsequent crystallization. Unfortunately, thermal treatment can generate toxic 5-hydroxymethylfurfural (HMF), thereby resulting in quality reduction. Considering this, the present work aims at evaluating the influence of (two) processing technologies as alternatives to thermal processing of honey, namely high hydrostatic pressure (HHP; P = 220–330 MPa, T = 50/60 °C, t = 23/106 min), and ultrasound processing (US; at 24 kHz). The quality parameters evaluated for honey included liquefaction time, HMF content, diastase number, co…
The effect of nickel on seed germination and plant sprouting in the case of some Alyssum species
2015
The aim of the researches was to establish the upper limit of nickel concentration in soils that the Alyssum maritimum and Alyssum murale species could tolerate without significantly affecting the germination and the plant sprouting process. The experiment was conducted in 4 variants of 3 repetitions, each repetition including 50 seeds. The watering process of the substrate was performed using distilled water for the control variant (M) and NiSO4 solutions that represented the intervention threshold (V1 – 150 mg/kg) and doses that exceeded the intervention threshold (V2 – 350 mg/kg; V3 – 550 mg/kg and V4 – 750 mg/kg). The Ni influence on seed germination was assessed based on sprouting perc…
The contribution of P. acidilactici, L. plantarum, and L. curvatus starters and L-(+)-lactic acid to the acrylamide content and quality parameters of…
2017
Abstract Lactic acid bacteria (LAB) from spontaneous rye sourdough were isolated, identified, and characterized by their growth, acidification rate, and carbohydrate metabolism. The isolated LAB were used for production of rye sourdough, and the influence of sourdough on mixed rye - wheat bread quality and acrylamide formation was evaluated. In addition, comparative studies by using acidification with L-(+)-lactic acid for mixed rye – wheat bread production were performed. Isolated LAB (P. acidilactici, L. plantarum, L. curvatus) demonstrated versatile carbohydrate metabolism, grown at 30 °C and 37 °C, and acidic tolerance. When the isolated strains were used for rye sourdough production, t…
Antibacterial polypeptides of Lactobacillus species
1990
Twelve of 79 strains of the genus Lactobacillus, mainly isolated from plants or fermenting material, were found to inhibit at least one of the nine indicator strains of the species Lact. brevis, Pediococcus damnosus and Leucanostoc oenos. The antimicrobial activities from Lact. brevis B 37 and Lact. casei B 80 were caused by polypeptides detectable in the culture liquids. They are bacteriocins with a narrow antimicrobial spectrum. Brevicin 37 from Lact. brevis B 37 was active against many lactic acid bacteria and Nocardia corallina, whereas caseicin 80 from Lact. casei B 80 inhibits only one other strain of Lact. casei. Brevicin 37 is stable at 121dC, caseicin 80 is inactivated above 60dC, …
The effect of Pediococcus acidilactici and Lactobacillus sakei on biogenic amines formation and free amino acid profile in different lupin during fer…
2016
Abstract The effect of Pediococcus acidilactici and Lactobacillus sakei strains on biogenic amines (BAs) formation during submerged and solid state fermentation of Lupinus luteus and Lupinus angustifolius was analysed. The composition of lupin seeds was evaluated and the influence of fermentation on free amino acid (FAA) profile was investigated. The highest protein and carbohydrate contents were found in L. luteus var. ‘Vilciai’, the highest carbohydrate contents – in L. angustifolius hybrid lines No. 1701 and No. 1800, and fat – in L. angustifolius hybrid lines No. 1700, No. 1703 and No. 1734. The interaction between the fermentation method, the bacterial strains used and lupin varieties …
Antimicrobial and antistaphylococcal biofilm activity from the sea urchin Paracentrotus lividus
2010
Aims: Staphylococcal biofilm-associated infections are resistant to conventional antibiotics. Consequently, new agents are needed to treat them. With this aim, we focused on the effector cells (coelomocytes) of the sea urchin Paracentrotus lividus immune system. Methods and Results: We tested the activity of the 5-kDa peptide fraction of the cytosol from coelomocytes (5-CC) against a group of Gram-positive, Gram-negative bacteria and fungi. We determined minimal inhibitory concentrations (MICs) ranging from 253·7 to 15·8 mg ml−1. We observed an inhibitory activity and antibiofilm properties of 5-CC against staphylococcal biofilms of reference strains Staphylococcus epidermidis DSM 3269 an…
Targeting the Sortase A Transpeptidase to Tackle Gram-positive Pathogens
2013
The virulence factors include the cell-wall associated proteins called MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) that can promote the adhesion to host proteins, for example, the fibronectin that is very common in host tissues. The cellwall associated proteins are necessary for host colonization, invasion, immune evasion and biofilm formation [4]. The biofilms, multistratified bacterial communities that grow on a biological or artificial surface, are responsible for chronic infectious diseases and for device or biomaterial associated infections, and are more resistant to host immune defence system and to conventional antibiotics [5].
Effect of poly(I).poly(C12U) (Ampligen) on enteric virus (rotavirus, poliovirus and Coxsackie B3 virus) infections
1994
The effects of poly(1)-poly(C 12 U) (Ampligen) on infections with enteric viruses (rotavirus, poliovirus and Coxsackie B3 virus) were studied in vitro. Ampligen exhibited antiviral activity against rotavirus, especially when treatment was performed prior to inoculation of the virus. It was partially effective against Coxsackie B3 virus, but not against poliovirus. It is suggested that the observed effects may be due to the production of interferon induced by Ampligen
Nonlinear Feedback Control and Stability Analysis of a Proof-of-Work Blockchain
2017
In this paper a novel feedback controller and stability analysis of a blockchain implementation is developed by using a control engineering perspective. The controller output equals the difficulty adjustment in the mining process while the feedback variable is the average block time over a certain time period. The computational power (hash rate) of the miners is considered a disturbance in the model. The developed controller is tested against a simulation model with constant disturbance, step and ramp responses as well as with a high-frequency sinusoidal disturbance. Stability and a fast response is demonstrated in all these cases with a controller which adjusts it's output at every new blo…