Search results for "bacterial"

A screening of five Bacillus thuringiensis Vip3A proteins for their activity against lepidopteran pests

2014

Five Bacillus thuringiensis Vip3A proteins (Vip3Aa, Vip3Ab, Vip3Ad, Vip3Ae and Vip3Af) and their corresponding trypsin-activated toxins were tested for their toxicity against eight lepidopteran pests: Agrotis ipsilon, Helicoverpa armigera, Mamestra brassicae, Spodoptera exigua, Spodoptera frugiperda, Spodoptera littoralis, Ostrinia nubilalis and Lobesia botrana. Toxicity was first tested at a high dose at 7 and 10. days. No major differences were found when comparing protoxins vs. trypsin-activated toxins. The proteins that were active against most of the insect species were Vip3Aa, Vip3Ae and Vip3Af, followed by Vip3Ab. Vip3Ad was non-toxic to any of the species tested. Considering the res…

Specific Anti-Infective Immune Therapy

1997

From Immunogenic Mechanisms to Novel Therapeutic Approaches in Inflammatory Bowel Disease

2006

Crohn’s disease (CD) and ulcerative colitis (UC) are the two most common forms of chronic inflammatory bowel disease (IBD). The etiology of IBD is still unclear and should be considered as multi-factorial according to recent studies.1 Genetic factors seem to play a pathogenetic role as well as environmental, infectious and immulogical factors. Substantial progress, however, has been made in the understanding of the pathogenesis of IBD during the past years persuing the view, that IBD could result from disturbances of the intestinal barrier and a pathologic activation of the intestinal immune response towards luminal, bacterial antigens. This paradigm has led to the identification of key pla…

Hsp 56 mRNA in Paracentrotus lividus embryos binds to a mitochondrial protein

2007

We previously demonstrated that Paracentrotus lividus Hsp56 mitochondrial chaperonin is constitutively expressed during development, that it has a specific territorial distribution, both in normal and heat-shocked embryos, and that its amount increases after heat shock [Roccheri MC, Patti M, Agnello M, Gianguzza F, Carra E, Rinaldi AM. Localization of mitochondrial Hsp56 chaperonin during sea urchin development. Biochem Biophys Res Commun 2001;287:1093-98] and cadmium treatment [Roccheri MC, Agnello M, Boneventura R, Matranga V. Cadmium induces the expression of specific stress proteins in sea urchin embryos. Biochem Biophys Res Commun 2004;321:80-7]. In this study, we looked at Hsp56 mRNA …

High pressure processing of food-grade emulsion systems: Antimicrobial activity, and effect on the physicochemical properties

2019

Abstract The use of high pressure processing (HPP) for development of stable emulsion-based delivery systems has been recently increased. Under adequate conditions, application of high pressures modifies the functionality of protein and polysaccharide molecules and significantly promotes the emulsifying activities. Application of high pressures also modulates the emulsion microstructure without any destabilization and gelation of protein molecules. The lipid oxidation in HPP-treated emulsions can be accelerated, particularly with higher pressure levels, while the HPP utilization on emulsions in acidic conditions can highly inhibit the growth of spoilage and pathogenic microorganisms. In thi…

Variety of size and form of GRM2 bacterial microcompartment particles

2021

Bacterial microcompartments (BMCs) are bacterial organelles involved in enzymatic processes, such as carbon fixation, choline, ethanolamine and propanediol degradation, and others. Formed of a semi‐permeable protein shell and an enzymatic core, they can enhance enzyme performance and protect the cell from harmful intermediates. With the ability to encapsulate non‐native enzymes, BMCs show high potential for applied use. For this goal, a detailed look into shell form variability is significant to predict shell adaptability. Here we present four novel 3D cryo‐EM maps of recombinant Klebsiella pneumoniae GRM2 BMC shell particles with the resolution in range of 9 to 22 Å and nine novel 2D class…

Contribution of exofacial thiol groups in the reducing activity of Lactococcus lactis

2010

Lactococcus lactis can decrease the redox potential at pH 7 (E(h7)) from 200 to -200 mV in oxygen free Man-Rogosa-Sharpe media. Neither the consumption of oxidizing compounds or the release of reducing compounds during lactic acid fermentation were involved in the decrease in E(h7) by the bacteria. Thiol groups located on the bacterial cell surface appear to be the main components that are able to establish a greater exchange current between the Pt electrode and the bacteria. After the final E(h7) (-200 mV) was reached, only thiol-reactive reagents could restore the initial E(h7) value. Inhibition of the proton motive force showed no effect on maintaining the final E(h7) value. These result…

Ability of Kocuria varians LTH 1540 To Degrade Putrescine: Identification and Characterization of a Novel Amine Oxidase.

2015

This work describes the identification and characterization of an amine oxidase from Kocuria varians LTH 1540 (syn. Micrococcus varians) primarily acting on putrescine. Data from MALDI-TOF MS/MS and the identification of Δ(1)-pyrroline as degradation product from putrescine indicate that the enzyme is a flavin-dependent putrescine oxidase (PuO). Properties of partially purified enzyme have been determined. The enzyme oxidizes diamines, putrescine and cadaverine, and, to a lesser extent, polyamines, such as spermidine, but not monoamines. The kinetic constants (Km and Vmax) for the two major substrates were 94 ± 10 μM and 2.3 ± 0.1 μmol/min·mg for putrescine and 75 ± 5 μM and 0.15 ± 0.02 μmo…

The NreA Protein Functions as a Nitrate Receptor in the Staphylococcal Nitrate Regulation System

2013

Staphylococci are able to use nitrate as an alternative electron acceptor during anaerobic respiration. The regulation of energy metabolism is dependent on the presence of oxygen and nitrate. Under anaerobic conditions, staphylococci employ the nitrate regulatory element (Nre) for transcriptional activation of genes involved in reduction and transport of nitrate and nitrite. Of the three proteins that constitute the Nre system, NreB has been characterized as an oxygen sensor kinase and NreC has been characterized as its cognate response regulator. Here, we present structural and functional data that establish NreA as a new type of nitrate receptor. The structure of NreA with bound nitrate w…

α-L-rhamnosidases: Old and New Insights

2007

L-Rhamnose is a component of plant cell wall pectic polysaccharides (Mutter et al., 1994; Ridley et al., 2001), glycoproteins (Haruko and Haruko, 1999) and secondary metabolites such as anthocyanins (Renault et al., 1997), flavonoids (Bar-Peled et al., 1991) and triterpenoids (Friedman and McDonald, 1997). It has also been found in bacterial heteropolysaccharides (Hashimoto and Murata, 1998), rhamnolipids (Ochsner et al., 1994) and in the repeating units of the O-antigen structure of the lipopolysaccharide component of bacterial outer membranes (Chua et al., 1999). Some rhamnosides are important bioactive compounds, e.g. cytotoxic saponins (Bader et al., 1998; Yu et al., 2002), antifungal p…