Search results for "microorganism"

Structural analysis of the lipid A isolated from Hafnia alvei 32 and PCM 1192 lipopolysaccharides[S]

2010

Hafnia alvei, a Gram-negative bacterium, is an opportunistic pathogen associated with mixed hospital infections, bacteremia, septicemia, and respiratory diseases. The majority of clinical symptoms of diseases caused by this bacterium have a lipopolysaccharide (LPS, endotoxin)-related origin. The lipid A structure affects the biological activity of endotoxins predominantly. Thus, the structure of H. alvei lipid A was analyzed for the first time. The major form, asymmetrically hexa-acylated lipid A built of beta-D-GlcpN4P-(1-->6)-alpha-D-GlcpN1P substituted with (R)-14:0(3-OH) at N-2 and O-3, 14:0(3-(R)-O-12:0) at N-2', and 14:0(3-(R)-O-14:0) at O-3', was identified by ESI-MS(n) and MALDI-tim…

High gas pressure: An innovative method for the inactivation of dried bacterial spores

2012

In this article, an original non-thermal process to inactivate dehydrated bacterial spores is described. The use of gases such as nitrogen or argon as transmission media under high isostatic pressure led to an inactivation of over 2 logs CFU/g of Bacillus subtilis spores at 430 MPa, room temperature, for a 1 min treatment. A major requirement for the effectiveness of the process resided in the highly dehydrated state of the spores. Only a water activity below 0.3 led to substantial inactivation. The solubility of the gas in the lipid components of the spore and its diffusion properties was essential to inactivation. The main phenomenon involved seems to be the sorption of the gas under pres…

Cell surface properties affect colonisation of raw milk by lactic acid bacteria at the microstructure level

2010

Cell localisation in the matrix microstructure of fermented food is important for microbial activity and ripening. To evaluate the importance of physicochemical factors in these phenomena, the physicochemical behaviour of four strains of lactic acid bacteria were investigated after inoculation of raw milk or milk fractions. To discriminate between physicochemical and metabolic properties, media were (i) rapidly acidified to avoid cell division or (ii) bacteria were allowed to ferment milk. To evaluate the impact of milk components, cells were dispersed in protein or fatty globule fractions. From two Lactococcus lactis subsp. lactis biovar. diacetylactis strains selected from their different…

Prospects of in vivo 31P NMR method in glyphosate degradation studies in whole cell system

2009

Abstract The degradation of the phosphonate herbicide glyphosate ( N -phosphonomethylglycine) by four taxonomically distinct microorganisms was studied in vivo in whole cell system using phosphorus nuclear magnetic spectroscopy ( 31 P NMR). The time-course of glyphosate metabolization in dense cell cultures was followed by means of 31 P NMR up to 21 days after the addition. The results obtained by this non-invasive way confirmed that the cells of Spirulina platensis and Streptomyces lusitanus biodegrade herbicide. Moreover, phosphorus starvation influenced the rate of glyphosate degradation by S. platensis . On the other hand, the results of similar measurements in the cultures of green alg…

Influence of type III bacterial secretion system on the interactions between plant and non pathogenic fluorescent Pseudomonads spp.

2010

No abstract

Microbial strategies to improve the final quality of traditional Sicilian cheeses

Evaluation of dermal toxicity of antibacterial cotton textile coated by sol-gel technology

2017

AbstractThis paper reports about cotton textile modification by sol-gel technology with the purpose of obtaining antibacterial properties, evaluation of antibacterial properties and dermal toxicity tests of cotton textile with Zn and Si coating. Antibacterial properties evaluation against pathogenic microorganisms Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli made using the Parallel streak method in accordance with ATCC147 standard. For more specific evaluation of the coated textile, in vitro cytotoxicity test with epidermal HaCat cells was done. It is concluded that the coatings containing Zn and Si obtained by the sol-gel technology can impart antibacterial propertie…

Experimental Evaluation of a New Thermal Process for Microorganisms Inactivation

2015

A new thermal process for the inactivation of microorganisms in beverages has been studied and is presented in this paper. The treatment, not yet studied in the scientific literature, mainly consists of a thermal shock characterized by temperature increases up to 30°C/s, with final temperatures up to 65°C. This study presents the first experimental results obtained by the application of the new thermal treatment, with different combinations of the process parameters (rate of temperature rise, final temperature and holding time), on separate suspensions of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Listeria innocua and Candida albicans. The required rapid temperature in…

Influence of native microbiota on survival of Ralstonia solanacearum phylotype II in river water microcosms.

2007

ABSTRACT Ralstonia solanacearum phylotype II biovar 2 causes bacterial wilt in solanaceous hosts, producing severe economic losses worldwide. Waterways can be major dissemination routes of this pathogen, which is able to survive for long periods in sterilized water. However, little is known about its survival in natural water when other microorganisms, such as bacteriophages, other bacteria, and protozoa, are present. This study looks into the fate of a Spanish strain of R. solanacearum inoculated in water microcosms from a Spanish river, containing different microbiota fractions, at 24°C and 14°C, for a month. At both temperatures, R. solanacearum densities remained constant at the initial…

Fermentation profiles of Manzanilla-Aloreña cracked green table olives in different chloride salt mixtures.

2010

NaCl plays an important role in table olive processing affecting the flavour and microbiological stability of the final product. However, consumers demand foods low in sodium, which makes necessary to decrease levels of this mineral in fruits. In this work, the effects of diverse mixtures of NaCl, CaCl2 and KCl on the fermentation profiles of cracked directly brined Manzanilla-Aloreña olives, were studied by means of response surface methodology based in a simplex lattice mixture design with constrains. All salt combinations led to lactic acid processes. The growth of Enterobacteriaceae populations was always limited and partially inhibited by the presence of CaCl2. Only time to reach half …