The Human Digestive Tract Is Capable of Degrading Gluten from Birth.

The human gastrointestinal system has the capacity to metabolize dietary gluten. The capacity to degrade gliadin-derived peptide is present in humans from birth and increases during the first stages of life (up to 6-12 months of age). Fecal samples from 151 new-born and adult non-celiac disease (NCD) volunteers were collected, and glutenase and glianidase activities were evaluated.

Evaluation of bacterial adhesion in exposed orbital implants using electron microscopy and microbiological culture.

Three cases are presented of anophthalmic patients with exposed orbital implants. Although only one patient showed evident clinical signs of infection, all three implants were studied to determine the presence of microorganisms adhered to their surface using a scanning electron microscopy (SEM) and microbiological culture. The SEM allowed the visualisation of microorganisms adhered to the three implants, although only one of them showed growth in the microbiological cultures.

Conjunctival flora in anophthalmic patients: microbiological spectrum and antibiotic sensitivity.

Aim: To identify the spectrum and susceptibility pattern of isolated microorganisms from conjunctival flora of anophthalmic patients.

Methods: A cross-sectional clinical study including 60 patients with unilateral anophthalmia. Patients with use of antibiotic drops in their socket during the last month were also included.

The role of RcsA in the adaptation and survival of Escherichia coli K92.

The Rcs phosphorelay is a two-component signal transduction system that senses stressful environmental signals such as desiccation or low temperatures, which serve as natural inducers in bacteria. RcsA is an important coregulator in this system involved in some functions regulated by the Rcs system, including biofilm formation and capsule synthesis. In this sense, we previously showed that RcsA is necessary for colanic acid synthesis in Escherichia coli K92.

adherence of conjunctival bacteria to different oculoplastic materials.

Aim: To investigate the resistance to bacterial adhesion of materials used in oculoplastic surgery, particularly materials used in the manufacture of orbital implants.

Methods: Seven organisms of conjunctival flora (two strains of and one strain each of , , , , and ) were selected. A lactic acid bacterium () was also included as positive control because of its well-known adhesion ability.

The human digestive tract has proteases capable of gluten hydrolysis.

Objective: To identify, purify, and characterize the proteins responsible for glutenase activity in the feces of healthy subjects and patients with celiac disease (CD).

Methods: Sixteen subjects were included in this study; 8 were healthy with no known food intolerances, and 8 were treated CD patients on a gluten-free diet. Fecal samples were homogenized, and precipitated proteins were purified by chromatography.

Study of conjunctival flora in anophthalmic patients: influence on the comfort of the socket.

Purpose: To investigate the relationship between conjunctival flora and comfort of the socket in anophthalmic patients.

Methods: A cross-sectional clinical study including 60 patients with unilateral anophthalmia who wear a prosthetic eye. From each patient three microbiological samples were taken from the lower conjunctival sac (healthy eye, pre-prosthesis, and retro-prosthesis space of socket).

The Usefulness of Non-Toxic Plant Metabolites in the Control of Bacterial Proliferation.

The effect of generally recognised as safe (GRAS) plant metabolites in regulating the growth of human pathogenic and probiotic bacteria and in the formation of biofilm was investigated. Thymol, carvacrol and eugenol showed the strongest antibacterial action against both pathogenic and probiotic microorganisms, at a subinhibitory concentration (SIC) of ≤50 μg ml. Genistein, hydroquinone, p-hydroxybenzoic acid and resveratrol also showed antibacterial effects but at a wide concentration range (SIC = 50-1000 μg ml).

Effect of fermented broth from lactic acid bacteria on pathogenic bacteria proliferation.

In this study, the effect that 5 fermented broths of lactic acid bacteria (LAB) strains have on the viability or proliferation and adhesion of 7 potentially pathogenic microorganisms was tested. The fermented broth from Lactococcus lactis C660 had a growth inhibitory effect on Escherichia coli K92 that reached of 31%, 19% to Pseudomonas fluorescens, and 76% to Staphylococcus epidermidis. The growth of Staph.

Non-toxic plant metabolites regulate Staphylococcus viability and biofilm formation: a natural therapeutic strategy useful in the treatment and prevention of skin infections.

In the present study, the efficacy of generally recognised as safe (GRAS) antimicrobial plant metabolites in regulating the growth of Staphylococcus aureus and S. epidermidis was investigated. Thymol, carvacrol and eugenol showed the strongest antibacterial action against these microorganisms, at a subinhibitory concentration (SIC) of ≤ 50 μg ml(-1).

Transcriptional control of RfaH on polysialic and colanic acid synthesis by Escherichia coli K92.

The transcriptional antiterminator RfaH promotes transcription of long operons encoding surface cell components important for the virulence of Escherichiacoli pathogens. In this paper, we show that RfaH enhanced kps expression for the synthesis of group 2 polysialic acid capsule in E. coli K92.

Polysialic and colanic acids metabolism in Escherichia coli K92 is regulated by RcsA and RcsB.

We have shown previously that Escherichia coli K92 produces two different capsular polymers known as CA (colanic acid) and PA (polysialic acid) in a thermoregulated manner. The complex Rcs phosphorelay is largely related to the regulation of CA synthesis. Through deletion of rscA and rscB genes, we show that the Rcs system is involved in the regulation of both CA and PA synthesis in E.

Growth temperature regulation of some genes that define the superficial capsular carbohydrate composition of Escherichia coli K92.

We studied growth temperature as a factor controlling the expression of genes involved in capsular polymers of Escherichia coli K92. These genes are shown to be regulated by growth temperature. Expression levels of genes belonging to the kps cluster, responsible for polysialic acid (PA) biosynthesis, were significantly increased at 37 °C compared with at 19 °C, being up to 500-fold increased for neuE and neuS genes.

Temperature has reciprocal effects on colanic acid and polysialic acid biosynthesis in E. coli K92.

Escherichia coli K92 is an opportunistic pathogen bacterium able to produce polysialic acid (PA) capsules when grows at 37 degrees C. PA polysaccharides are cell-associated homopolymers tailored from acid sialic monomers that function as virulence factors in different neuroinvasive diseases caused by certain Enterobacteriaceae. Conversely, when grows at 19 degrees C (restrictive conditions), PA synthesis was negligible, whereas in such condition, a slimy substance started to be accumulated in the culture broths.

Purification and characterization of GlcNAc-6-P 2-epimerase from Escherichia coli K92.

N-Acetylmannosamine (ManNAc) is the first committed intermediate in sialic acid metabolism. Thus, the mechanisms that control intracellular ManNAc levels are important regulators of sialic acid production. In prokaryotic organisms, UDP-N-acetylglucosamine (GlcNAc) 2-epimerase and GlcNAc-6-P 2-epimerase are two enzymes capable of generating ManNAc from UDP-GlcNAc and GlcNAc-6-P, respectively.

Transport of N-acetyl-D-galactosamine in Escherichia coli K92: effect on acetyl-amino sugar metabolism and polysialic acid production.

The N-acetyl-D-galactosamine (GalNAc) transport system of Escherichia coli K92 was studied when the bacterium was grown in a chemically defined medium containing GalNAc as a carbon source. Kinetic measurements were carried out in vivo at 37 degrees C in 25 mM phosphate buffer, pH 7.0.

Application of a normalised plot to the study of uni-uni enzyme-inhibitor systems.

Normalisation of kinetic data is a useful tool in the study of complex enzyme systems. In the present paper, we have applied the premises of the normalised plot to the description of uni-uni enzyme inhibition. Guidelines to the design of the experiments and to data managing using the freeware program SIMFIT (http:\\www.

Transport of N-acetyl-D-mannosamine and N-acetyl-D-glucosamine in Escherichia coli K1: effect on capsular polysialic acid production.

N-Acetyl-D-mannosamine (ManNAc) and N-acetyl-D-glucosamine (GlcNAc) are the essential precursors of N-acetylneuraminic acid (NeuAc), the specific monomer of polysialic acid (PA), a bacterial pathogenic determinant. Escherichia coli K1 uses both amino sugars as carbon sources and uptake takes place through the mannose phosphotransferase system transporter, a phosphoenolpyruvate-dependent phosphotransferase system that shows a broad range of specificity. Glucose, mannose, fructose, and glucosamine strongly inhibited the transport of these amino-acetylated sugars and GlcNAc and ManNAc strongly affected ManNAc and GlcNAc uptake, respectively.

N-Acetylneuraminic acid uptake in Pasteurella (Mannheimia) haemolytica A2 occurs by an inducible and specific transport system.

The N-acetylneuraminic acid (NeuAc) transport system of Pasteurella (Mannheimia) haemolytica A2 was studied when this bacterium was grown in both complex and chemically defined media. Kinetic measurements were carried out at 37 degrees C in 50 mM Tris-HCl buffer, pH 8.0, containing 50 microg/ml bovine serum albumin.

Kinetic properties of the acylneuraminate cytidylyltransferase from Pasteurella haemolytica A2.

Neuroinvasive and septicaemia-causing pathogens often display a polysialic acid capsule that is involved in invasive behaviour. N-Acetylneuraminic acid (NeuAc) is the basic monomer of polysialic acid. The activated form, CMP-Neu5Ac, is synthesized by the acylneuraminate cytidylyltransferase (ACT; EC 2.

A normalized plot as a novel and time-saving tool in complex enzyme kinetic analysis.

A new data treatment is described for designing kinetic experiments and analysing kinetic results for multi-substrate enzymes. Normalized velocities are plotted against normalized substrate concentrations. Data are grouped into n + 1 families across the range of substrate or product tested, n being the number of substrates plus products assayed.

Determination of different amino sugar 2'-epimerase activities by coupling to N-acetylneuraminate synthesis.

A new procedure for quantitating the amount of N-acetyl-D-mannosamine (ManNAc) or ManNAc-6-phosphate produced by 2'-epimerase activities involved in sialic acid metabolism has been developed. The ManNAc generated by the action of N-acetyl-D-glucosamine (GlcNAc) and UDP-GlcNAc 2'-epimerases is condensed with pyruvate through the action of N-acetylneuraminate lyase and the sialic acid released is measured by the thiobarbituric acid assay. For the analysis of prokaryotic GlcNAc-6-phosphate 2'-epimerase, ManNAc-6-phosphate can also be evaluated by this coupled assay after dephosphorylation of the sugar phosphate.

Regulation of capsular polysialic acid biosynthesis by temperature in Pasteurella haemolytica A2.

The capsular polysaccharide of Pasteurella haemolytica A2 consists of a linear polymer of N-acetylneuraminic acid (Neu5Ac) with alpha(2-8) linkages. The production of this polymer is strictly regulated by the growth temperature and above 40 degrees C no production is detected. Analysis of the enzymatic activities directly involved in its biosynthesis reveals that Neu5Ac lyase, CMP-Neu5Ac synthetase and polysialyltransferase are involved in this regulation.

Molecular cloning and expression in different microbes of the DNA encoding Pseudomonas putida U phenylacetyl-CoA ligase. Use of this gene to improve the rate of benzylpenicillin biosynthesis in Penicillium chrysogenum.

The gene encoding phenylacetyl-CoA ligase (pcl), the first enzyme of the pathway involved in the aerobic catabolism of phenylacetic acid in Pseudomonas putida U, has been cloned, sequenced, and expressed in two different microbes. In both, the primary structure of the protein was studied, and after genetic manipulation, different recombinant proteins were analyzed. The pcl gene, which was isolated from P.

Inhibition of penicillin biosynthetic enzymes by halogen derivatives of phenylacetic acid.

The effect of phenylacetic acid (PAA) and several analogs on the activity of isopenicillin N synthase (IPNS) and acyl-CoA: 6-APA acyltransferase (AT) from Penicillium chrysogenum Wis 54-1255 has been tested. Whereas the substitution on the ring of a hydrogen atom by hydroxy-, methyl- or methoxy- groups did not cause any effect, the presence of halogens (Cl or Br) at positions 3 and/or 4 of PAA strongly inhibited these two enzymes. The replacement of hydrogen atoms by fluorine in certain positions also caused inhibition, but to a lesser extent.