Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 35
Filter
1.
Bone ; 157: 116339, 2022 04.
Article in English | MEDLINE | ID: mdl-35051679

ABSTRACT

BACKGROUND: Type 2 diabetes (T2D) is associated with increased fracture risk, despite similar or greater BMD compared to nondiabetics. TBS predicts fracture risk in T2D and nondiabetics. However, increased abdominal thickness, a common feature in T2D, may reduce TBS values. AIM: To study the relationship among glycemic status, BMD and TBS, considering abdominal soft tissue thickness (STT) interference. METHODS: Cross-sectional analysis of 493 women ≥65 years, with simultaneous DXA scans and HbA1c measures. STT and TBS (iNsight Software, v3.0) were derived from lumbar spine (LS) scans. Subjects were divided according to HbA1c levels: 1 (≥6.5%; n = 116), 2 (5.7-6.4%; n = 217) and 3 (≤5.6%; n = 160). Group 1 was further divided based on HbA1c and/or disease duration: 1a (HbA1c ≥ 7.5%; n = 42), 1b (HbA1c ≥ 6.5% and disease duration ≥5 years; n = 63) and 1c (HbA1c ≥ 7.5% and disease duration ≥5 years; n = 30). FINDINGS: For the entire cohort, mean age, TBS, BMI and STT were 71.8 ± 6.0 years, 1.299 ± 0.101, 26.9 ± 4.1 kg/m2, and 21.4 ± 2.9 cm, respectively. LS-BMD was similar among groups. BMD in hip sites and STT were higher in group 1. TBS was lower in patients with higher HbA1c (P = 0.020), with a mean TBS in groups 1, 2, and 3 of 1.280, 1.299 and 1.314, respectively. This difference remained after adjusting for age, LS-BMD and BMI (P = 0.010). After replacing BMI with STT, TBS differences were no longer significant (P = 0.270). The same was observed when subgroups 1a and 1b were compared to group 3. However, for subgroup 1c, TBS remained lower compared to group 3, even after adjusting for age, LS-BMD and STT, with a borderline P-value (1.275 vs. 1.308; P = 0.047). CONCLUSION: Higher HbA1c levels were associated with greater BMD in hip sites, higher abdominal STT and lower TBS values. However, after including the STT in the adjustment, TBS differences among groups disappeared, except in women with higher HbA1c levels and longer disease duration.


Subject(s)
Diabetes Mellitus, Type 2 , Fractures, Bone , Osteoporotic Fractures , Absorptiometry, Photon , Aged , Bone Density , Cancellous Bone/diagnostic imaging , Cross-Sectional Studies , Diabetes Mellitus, Type 2/complications , Female , Fractures, Bone/complications , Glycated Hemoglobin , Humans , Lumbar Vertebrae/diagnostic imaging , Osteoporotic Fractures/complications , Postmenopause
2.
Molecules ; 27(1)2022 Jan 03.
Article in English | MEDLINE | ID: mdl-35011508

ABSTRACT

The molecular hybridization approach has been used to develop compounds with improved efficacy by combining two or more pharmacophores of bioactive scaffolds. In this context, hybridization of various relevant pharmacophores with phenothiazine derivatives has resulted in pertinent compounds with diverse biological activities, interacting with specific or multiple targets. In fact, the development of new drugs or drug candidates based on phenothiazine system has been a promising approach due to the diverse activities associated with this tricyclic system, traditionally present in compounds with antipsychotic, antihistaminic and antimuscarinic effects. Actually, the pharmacological actions of phenothiazine hybrids include promising antibacterial, antifungal, anticancer, anti-inflammatory, antimalarial, analgesic and multi-drug resistance reversal properties. The present review summarizes the progress in the development of phenothiazine hybrids and their biological activity.


Subject(s)
Drug Development , Phenothiazines , Animals , Humans , Phenothiazines/chemical synthesis , Phenothiazines/chemistry , Phenothiazines/therapeutic use , Structure-Activity Relationship
3.
Food Chem Toxicol ; 132: 110647, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31260710

ABSTRACT

The main goal of this work is the encapsulation of cinnamon essential oil in cyclodextrin nanosponges and the assessment of their antimicrobial activity against foodborne pathogens. After nanosponge synthesis, a headspace-solid phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) method was validated to quantify essential oil major compounds. Results showed that essential oil was successfully encapsulated in cyclodextrin nanosponges with α-NS and ß-NS being able to encapsulate higher essential oil amounts. Cinnamon essential oil, alone and encapsulated in nanosponges, proved to have antimicrobial activity against foodborne bacteria. Time-kill assays proved that the essential oil, alone or encapsulated, had a bacteriostatic effect against all bacteria tested, with the exception of Y. enterocolitica where a bactericidal action was observed. Furthermore, the controlled release achieved by its encapsulation, allowed cinnamon essential oil to be effective at a much lower concentration in culture medium than when solely dissolved in culture medium. Thus, the results described herein encourage the use of cyclodextrin nanosponges as encapsulating agents for active food packaging applications.


Subject(s)
Anti-Bacterial Agents/pharmacology , Food Packaging , Nanostructures/chemistry , Oils, Volatile/pharmacology , Plant Oils/pharmacology , beta-Cyclodextrins/pharmacology , Anti-Bacterial Agents/chemistry , Brochothrix/drug effects , Escherichia coli/drug effects , Listeria monocytogenes/drug effects , Microbial Sensitivity Tests , Oils, Volatile/chemistry , Plant Oils/chemistry , Yersinia enterocolitica/drug effects , beta-Cyclodextrins/chemistry
4.
Eur J Pharm Sci ; 137: 104964, 2019 Sep 01.
Article in English | MEDLINE | ID: mdl-31233866

ABSTRACT

Acinetobacter baumannii has emerged as an important nosocomial pathogen in recent years, with infectious outbreaks caused by multidrug-resistant strains increasing worldwide. Thus, new antibacterial treatments for multidrug-resistant A. baumannii strains are needed. In this work, a series of 5-hydrazinylethylidenepyrimidines were synthesized and in vitro evaluated against two multidrug-resistant A. baumannii strains (AcB 13/10 and AcB 73/10). Minimum inhibitory concentration results demonstrated that generally the compounds in study presented values in a low micromolar range. In the determination of in vitro bacterial growth at 24 h, it was observed that the pyrimidines 3a and 3c, with an unsubstituted hydrazinylphenyl, have bacteriostatic activity in both multidrug-resistant A. baumannii strains, with a concentration-dependent action. In general, an additive effect occurred in the combination of these compounds with gentamicin, rifampicin and polymyxin B, for both strains. Furthermore, all 5-hydrazinylethylidenepyrimidines under study presented a good 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, generally low xanthine oxidase inhibition and low cytotoxicity in normal human dermal fibroblasts as well as potential favorable drug-likeness properties. Thus, these molecules can be considered attractive for the future development of antibacterial agents against multidrug-resistant A. baumannii.


Subject(s)
Acinetobacter baumannii/drug effects , Anti-Bacterial Agents/pharmacology , Free Radical Scavengers/pharmacology , Pyrimidines/pharmacology , Acinetobacter baumannii/growth & development , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacokinetics , Anti-Bacterial Agents/toxicity , Biphenyl Compounds/chemistry , Cell Line , Cell Survival/drug effects , Computer Simulation , Drug Resistance, Multiple, Bacterial/drug effects , Escherichia coli/drug effects , Escherichia coli/growth & development , Fibroblasts/drug effects , Free Radical Scavengers/chemistry , Free Radical Scavengers/pharmacokinetics , Free Radical Scavengers/toxicity , Humans , Microbial Sensitivity Tests , Models, Biological , Picrates/chemistry , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/growth & development , Pyrimidines/chemistry , Pyrimidines/pharmacokinetics , Pyrimidines/toxicity , Xanthine Oxidase/chemistry
5.
J Glob Antimicrob Resist ; 16: 130-139, 2019 03.
Article in English | MEDLINE | ID: mdl-30611931

ABSTRACT

OBJECTIVES: Over the years, an increased prevalence of resistant strains of Arcobacter has been observed, which may be due to Arcobacter exposure to antibiotics used both in animal production and human medicine. A systematic review was performed with the objective of summarising the results of the rates of antimicrobial resistance of Arcobacter isolates. METHODS: The systematic review was performed according to PRISMA (Preferred Reported Items for Systematic Reviews and Meta-Analysis) recommendations, followed by meta-analysis. RESULTS: It was observed that the resistance rate ranged between 69.3-99.2% for penicillins and 30.5-97.4% for cephalosporins. The overall percentage of resistance to fluoroquinolones ranged from 4.3% to 14.0%, with the highest resistance percentage observed for levofloxacin. Resistance rates ranged between 10.7-39.8% for macrolides, 1.8-12.9% for aminoglycosides and 0.8-7.1% for tetracyclines. CONCLUSIONS: These results show that Arcobacter spp. present resistance to various antibiotics commonly used and advocate further studies of the associated resistance mechanisms.


Subject(s)
Anti-Bacterial Agents/pharmacology , Arcobacter/drug effects , Drug Resistance, Multiple, Bacterial , Animals , Arcobacter/genetics , Humans , Microbial Sensitivity Tests
6.
Microb Drug Resist ; 24(7): 915-922, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29336679

ABSTRACT

Arcobacter butzleri is a widely distributed emerging pathogen resistant to various classes of antimicrobial agents, namely fluoroquinolones. A. butzleri resistance to fluoroquinolones is conferred by point mutations at the antibiotic target. The aim of this study was to evaluate mutations at gyrA associated with ciprofloxacin resistance and evaluate whether acquisition of resistance impacts on fitness and stress tolerance of A. butzleri. A. butzleri ciprofloxacin mutants were generated by laboratory induction. Identification of mutations associated with ciprofloxacin resistance was performed by gyrA sequencing. Growth kinetics, cost of fitness, biofilm formation ability, and stress tolerance were assessed. Two amino acid substitutions in the quinolone resistance-determining region of GyrA were identified in the mutant strains, one previously described (Thr-85-Ile) and a new substitution (Asp-89-Tyr). No differences in growth kinetics were recorded between parental and mutant strains; however, fitness cost was variable, according to the genetic background of the strains, and independently of ciprofloxacin resistance. Overall, the ciprofloxacin resistance development did not significantly affect stress tolerance, motility, or biofilm-forming ability. In conclusion, acquisition of ciprofloxacin resistance in A. butzleri is associated with mutations in gyrA and is likely well compensated, with cost of fitness reflecting the diversity in genetic background of this bacterium.


Subject(s)
Arcobacter/drug effects , Arcobacter/genetics , Ciprofloxacin/pharmacology , DNA Gyrase/genetics , Drug Resistance, Bacterial/drug effects , Drug Resistance, Bacterial/genetics , Point Mutation/genetics , Amino Acid Substitution/genetics , Anti-Bacterial Agents/pharmacology , Biofilms/drug effects , Fluoroquinolones/pharmacology , Microbial Sensitivity Tests/methods , Quinolones/pharmacology
7.
Crit Rev Food Sci Nutr ; 58(4): 591-609, 2018 Mar 04.
Article in English | MEDLINE | ID: mdl-27438696

ABSTRACT

Fresh poultry meat and poultry products are highly perishable foods and high potential sources of human infection due to the presence of several foodborne pathogens. Focusing on the microbial control of poultry products, the food industry generally implements numerous preventive measures based on the Hazard Analysis and Critical Control Points (HACCP) food safety management system certification together with technological steps, such as refrigeration coupled to modified atmosphere packaging that are able to control identified potential microbial hazards during food processing. However, in recent years, to meet the demand of consumers for minimally processed, high-quality, and additive-free foods, technologies are emerging associated with nonthermal microbial inactivation, such as high hydrostatic pressure, irradiation, and natural alternatives, such as biopreservation or the incorporation of natural preservatives in packaging materials. These technologies are discussed throughout this article, emphasizing their pros and cons regarding the control of poultry microbiota and their effects on poultry sensory properties. The discussion for each of the preservation techniques mentioned will be provided with as much detail as the data and studies provided in the literature for poultry meat and products allow. These new approaches, on their own, have proved to be effective against a wide range of microorganisms in poultry meat. However, since some of these emergent technologies still do not have full consumer's acceptability and, taking into consideration the hurdle technology concept for poultry processing, it is suggested that they will be used as combined treatments or, more frequently, in combination with modified atmosphere packaging.


Subject(s)
Food Microbiology/methods , Food Preservation/methods , Poultry Products/microbiology , Food Additives , Food Handling , Microbial Viability
8.
Eur J Med Chem ; 143: 829-842, 2018 Jan 01.
Article in English | MEDLINE | ID: mdl-29223098

ABSTRACT

Barbituric and thiobarbituric acid derivatives have become progressively attractive to medicinal chemists due to their wide range of biological activities. Herein, different series of 1,3,5-trisubstituted barbiturates and thiobarbiturates were prepared in moderate to excellent yields and their activity as xanthine oxidase inhibitors, antioxidants, antibacterial agents and as anti-proliferative compounds was evaluated in vitro. Interesting bioactive barbiturates were found namely, 1,3-dimethyl-5-[1-(2-phenylhydrazinyl)ethylidene]pyrimidine-2,4,6(1H,3H,5H)-trione (6c) and 1,3-dimethyl-5-[1-[2-(4-nitrophenyl)hydrazinyl]ethylidene]pyrimidine-2,4,6(1H,3H,5H)-trione (6e), which showed concomitant xanthine oxidase inhibitory effect (IC50 values of 24.3 and 27.9 µM, respectively), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC50 values of 18.8 and 23.8 µM, respectively). In addition, 5-[1-(2-phenylhydrazinyl)ethylidene]pyrimidine-2,4,6(1H,3H,5H)-trione (6d) also revealed DPPH radical scavenger effect, with an IC50 value of 20.4 µM. Moreover, relevant cytotoxicity against MCF-7 cells (IC50 = 13.3 µM) was observed with 5-[[(2-chloro-4-nitrophenyl)amino]methylene]-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (7d). Finally, different 5-hydrazinylethylidenepyrimidines revealed antibacterial activity against Acinetobacter baumannii (MIC values between 12.5 and 25.0 µM) which paves the way for developing new treatments for infections caused by this Gram-negative coccobacillus bacterium, known to be an opportunistic pathogen in humans with high relevance in multidrug-resistant nosocomial infections. The most promising bioactive barbiturates were studied in silico with emphasis on compliance with the Lipinski's rule of five as well as several pharmacokinetics and toxicity parameters.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antineoplastic Agents/pharmacology , Antioxidants/pharmacology , Bacteria/drug effects , Barbiturates/pharmacology , Enzyme Inhibitors/pharmacology , Xanthine Oxidase/antagonists & inhibitors , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Antioxidants/chemical synthesis , Antioxidants/chemistry , Bacteria/growth & development , Barbiturates/chemical synthesis , Barbiturates/chemistry , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , MCF-7 Cells , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity Relationship , Tumor Cells, Cultured , Xanthine Oxidase/metabolism
9.
J Food Sci Technol ; 54(1): 9-17, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28242898

ABSTRACT

The aim of this work was focused on the development of carboxymethyl xylan (CMX) formulations with functional properties to produce edible films. Beechwood Xylan was firstly derivatized into carboxymethyl xylan and thereafter was blended with Agar (Ag), Ammonium zirconium carbonate (AZC) and linoleic acid (La) to produce CMX:Ag, CMX:AZC, CMX:Ag:La films. Mechanical, barrier, optical and thermal properties of the produced films and their antimicrobial activity against food pathogenic bacteria were evaluated. The obtained films were transparent and yellowish. Agar and AZC improved the tensile strength at break of the control CMX film from 4.79 to 27.67 and 20.95 MPa respectively, and the CMX:AZC film exhibited the greatest elastic modulus. Barrier properties of the films decreased when any of the components was incorporated into the CMX and all blended films were thermally more stable than control. The CMX:Ag:La film revealed a good antimicrobial activity against B. cereus and S. aureus.

10.
Crit Rev Food Sci Nutr ; 57(1): 35-47, 2017 Jan 02.
Article in English | MEDLINE | ID: mdl-25831119

ABSTRACT

ABTRACT Foodborne illness represents a major economic burden worldwide and a serious public health threat, with around 48 million people affected and 3,000 death each year only in the USA. One of the possible strategies to reduce foodborne infections is the development of effective preservation strategies capable of eradicating microbial contamination of foods. Over the last years, new challenges for the food industry have arisen such as the increase of antimicrobial resistance of foodborne pathogens to common preservatives and consumers demand for naturally based products. In order to overcome this, new approaches using natural or bio-based products as food preservatives need to be investigated. Coriander (Coriandrum sativum L.) is a well-known herb widely used as spice, or in folk medicine, and in the pharmacy and food industries. Coriander seed oil is the world's second most relevant essential oil, exhibiting antimicrobial activity against Gram-positive and Gram-negative bacteria, some yeasts, dermatophytes and filamentous fungi. This review highlights coriander oil antimicrobial activity and possible mechanisms of action in microbial cells and discusses the ability of coriander oil usage as a food preservative, pointing out possible paths for the successful evolution for these strategies towards a successful development of a food preservation strategy using coriander oil.


Subject(s)
Anti-Infective Agents/chemistry , Coriandrum/chemistry , Food Preservatives/chemistry , Models, Biological , Oils, Volatile/chemistry , Plant Oils/chemistry , Seeds/chemistry , Acyclic Monoterpenes , Animals , Anti-Infective Agents/adverse effects , Anti-Infective Agents/metabolism , Consumer Behavior , Coriandrum/growth & development , Coriandrum/metabolism , Food Contamination/prevention & control , Food Preservation , Food Preservatives/adverse effects , Food Preservatives/metabolism , Food Technology/trends , Foodborne Diseases/prevention & control , Fungi/growth & development , Fungi/metabolism , Gram-Negative Bacteria/growth & development , Gram-Negative Bacteria/metabolism , Gram-Positive Bacteria/growth & development , Gram-Positive Bacteria/metabolism , Humans , Monoterpenes/adverse effects , Monoterpenes/chemistry , Monoterpenes/metabolism , Oils, Volatile/adverse effects , Oils, Volatile/metabolism , Plant Oils/adverse effects , Plant Oils/metabolism , Seeds/growth & development , Seeds/metabolism
11.
Article in English | MEDLINE | ID: mdl-27012918

ABSTRACT

Acinetobacter baumannii is an emerging pathogen associated with nosocomial infections that in addition has shown an increasing resistance to antibiotics. In this work the genetic diversity of A. baumannii isolates from a Portuguese hospital, their antibiotic resistance profiles and ability to form biofilms was studied. Seventy-nine clinical A. baumannii isolates were characterized by pulsed-field gel electrophoresis (PFGE) with 9 different PFGE profiles being obtained. Concerning the antimicrobial susceptibility, all A. baumannii isolates were resistant to 12 of the 17 tested antibiotics and classified as multidrug-resistant (MDR). In addition, 74.7% of the isolates showed biofilm formation ability, however no statistical significance with antibiotic resistance was observed. In contrast, urine samples isolates were more likely to form biofilms than strains isolated from other sources. Our findings highlight the high number of MDR A. baumannii isolates and the importance of the formation of biofilms as a potential virulence factor.


Subject(s)
Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/physiology , Biofilms/growth & development , Cross Infection/microbiology , Acinetobacter Infections/epidemiology , Acinetobacter Infections/prevention & control , Acinetobacter baumannii/genetics , Acinetobacter baumannii/isolation & purification , Anti-Bacterial Agents/pharmacology , Biofilms/drug effects , Drug Resistance, Multiple, Bacterial , Electrophoresis, Gel, Pulsed-Field , Emergency Service, Hospital , Humans , Portugal/epidemiology , Urine/microbiology
12.
Biofouling ; 32(2): 155-65, 2016.
Article in English | MEDLINE | ID: mdl-26901586

ABSTRACT

Acinetobacter baumannii is a pathogen that has the ability to adhere to surfaces in the hospital environment and to form biofilms which are increasingly resistant to antimicrobial agents. The aim of this work was to study the antimicrobial activity of the major oil compounds of Coriandrum sativum against A. baumannii. The effect of linalool on planktonic cells and biofilms of A. baumannii on different surfaces, as well as its effect on adhesion and quorum sensing was evaluated. From all the compounds evaluated, linalool was the compound with the best antibacterial activity, with minimum inhibitory concentration values between 2 and 8 µl ml(-1). Linalool also inhibited biofilm formation and dispersed established biofilms of A. baumannii, changed the adhesion of A. baumannii to surfaces and interfered with the quorum- sensing system. Thus, linalool could be a promising antimicrobial agent for controlling planktonic cells and biofilms of A. baumannii.


Subject(s)
Acinetobacter baumannii , Adhesiveness/drug effects , Biofilms/drug effects , Coriandrum , Monoterpenes/pharmacology , Plankton , Quorum Sensing/drug effects , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/pathogenicity , Acinetobacter baumannii/physiology , Acyclic Monoterpenes , Animals , Anti-Bacterial Agents/pharmacology , Humans , Microbial Sensitivity Tests , Oils, Volatile/pharmacology , Plankton/drug effects , Plankton/physiology
13.
Crit Rev Microbiol ; 42(3): 364-83, 2016 May.
Article in English | MEDLINE | ID: mdl-25806423

ABSTRACT

Arcobacter genus currently comprises 18 recognized species, among which Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii have been associated with human and animal disease. Although these organisms, with special emphasis A. butzleri, are emerging as clinical pathogens, several aspects of their epidemiology and virulence are only starting to be clarified. In vitro human and animal cell culture assays have been used to show that several Arcobacter species can adhere to and invade eukaryotic cells, induce an immune response and produce toxins that damage host cells. In addition, data from genome sequencing highlighted several potential markers that may be helpful candidates for the study and understanding of these mechanisms; however, more work is necessary to clarify the molecular mechanisms involved in Arcobacter virulence. Arcobacter can be considered a relatively robust organism showing to be able to survive in adverse conditions, as the ones imposed by food processing and storage. Moreover, these bacteria have shown increased antibiotic resistance, along with high multidrug resistance. In this review, we seek to update the state-of-the-art concerning Arcobacter distribution, its interaction with the host, the trends of antibiotic resistance, its ability to survive, and finally the use of natural antimicrobials for control of Arcobacter.


Subject(s)
Anti-Bacterial Agents/pharmacology , Arcobacter/drug effects , Arcobacter/pathogenicity , Drug Resistance, Bacterial , Gram-Negative Bacterial Infections/microbiology , Animals , Arcobacter/genetics , Arcobacter/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Humans , Virulence
14.
Ann Clin Biochem ; 52(Pt 4): 448-55, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25395544

ABSTRACT

BACKGROUND: Decreased serum concentrations of vitamin B12 are associated with Alzheimer's type dementia. The transcobalamin II gene (TCN2) 776C → G polymorphism affects transcobalamin II function as a carrier of vitamin B12 and might modify its availability. The association of the TCN2 776C → G polymorphism with Alzheimer's type dementia is unclear and was investigated in the present study. METHODS: Case-control study including 27 individuals diagnosed with Alzheimer's type dementia and 28 healthy controls. Serum concentrations of vitamin B12, homocysteine and other analytes were determined and the presence of TCN2 776C → G and 5, 10-methylenetetrahydrofolate reductase 1298A → C polymorphisms genotypes was ascertained by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Serum concentrations of vitamin B12 were lower while those of homocysteine were higher in patients than in controls (P < 0.05). The frequency of individuals carrying at least one 5, 10-methylenetetrahydrofolate reductase 1298C allele was higher (59% versus 32%) while frequency of individuals harbouring at least one TCN2 776G allele was lower (58% versus 86%) in patients than in controls (P < 0.05). Univariate logistic regression showed negative association of TCN2 776CG genotype with Alzheimer's type dementia (OR = 0.17 versus CC genotype, P < 0.02). Multivariate logistic regression identified TCN2 776C → G polymorphism as independent predictor of Alzheimer's type dementia together with higher concentrations of homocysteine, cholesterol and uric acid and lower concentrations of oestradiol. Association of TCN2 776C → G polymorphism with Alzheimer's type dementia was observed for individuals carrying the 5,10-methylenetetrahydrofolate reductase 1298AA genotype but not the AC or CC genotypes, indicating interaction between the two polymorphisms. CONCLUSIONS: The TCN2 776C → G polymorphism is negatively associated with Alzheimer's type dementia, suggesting a protective role against the disease in subjects with the 5, 10-methylenetetrahydrofolate reductase 1298AA genotype.


Subject(s)
Alzheimer Disease/genetics , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Polymorphism, Single Nucleotide/genetics , Transcobalamins/genetics , Aged , Alleles , Alzheimer Disease/blood , Biomarkers/analysis , Case-Control Studies , Female , Gene Frequency , Genotype , Humans , Male , Polymerase Chain Reaction , Prognosis , Tetrahydrofolates/blood , Vitamin B 12/blood
15.
Biotechnol Rep (Amst) ; 5: 7-13, 2015 Mar.
Article in English | MEDLINE | ID: mdl-28435804

ABSTRACT

Resveratrol is a plant secondary metabolite commonly found in peanuts and grapevines with significant health benefits. Recombinant organisms can produce large amounts of resveratrol and, in this work, Escherichia coli BW27784 was used to produce resveratrol in bioreactors while monitoring cell physiology and plasmid stability through flow cytometry and real-time qPCR, respectively. Initially, the influence of culture conditions and precursor addition was evaluated in screening assays and the data gathered was used to perform the bioreactor assays, allowing the production of 160 µg/mL of resveratrol. Cellular physiology and plasmid instability affected the final resveratrol production, with lower viability and plasmid copy numbers associated with lower yields. In sum, this study describes new tools to monitor the bioprocess, evaluating the effect of culture conditions, and its correlation with cell physiology and plasmid segregational stability, in order to define a viable and scalable bioprocess to fulfill the need for larger quantities of resveratrol.

16.
Microb Pathog ; 76: 19-25, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25218724

ABSTRACT

Even though Arcobacter butzleri has been implicated in some human disease as diarrhoea and bacteraemia, much of its pathogenesis and virulence factors remain unclear. In this work we have compared pathogenic and genotypic properties of six A. butzleri isolates from human and non-human sources. The tested isolates showed to be susceptible to tetracyclines and aminoglycosides, however non-human isolates were all resistant to quinolones. The ability to form biofilms was variable among the tested strains, and all of them showed a weak haemolytic activity. The presence of nine putative virulence genes was determined, with cadF, ciaB, cj1349, mviN, pldA, tlyA being detected in all strains, while irgA (3/6), hecA (5/6), hecB (4/6) were detected only in some strains. High levels of adhesion were observed for A. butzleri on Caco-2 cells, with pre-existing inflammation showing no significant effect on the adherence ability; yet variable levels of invasion were observed. A. butzleri isolates were able to survive intracellularly in Caco-2 cells and to induce a significant up-regulation of interleukin-8 secretion and structural cell rearrangements. These data brings new insights on A. butzleri virulence and highlights its pathogenic potential.


Subject(s)
Arcobacter/genetics , Arcobacter/physiology , Virulence Factors/genetics , Anti-Bacterial Agents/pharmacology , Arcobacter/isolation & purification , Arcobacter/pathogenicity , Bacteremia/microbiology , Bacterial Adhesion , Biofilms/growth & development , Caco-2 Cells , DNA, Bacterial/genetics , Diarrhea/microbiology , Epithelial Cells/microbiology , Genes, Bacterial , Genotype , Hemolysis , Humans , Interleukin-8/metabolism , Microbial Sensitivity Tests , Phenotype , Polymerase Chain Reaction
17.
Int J Antimicrob Agents ; 44(4): 306-13, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25130097

ABSTRACT

Infections by Campylobacter jejuni and Campylobacter coli are considered the major cause of bacterial gastroenteritis in humans, with food being the main source of infection. In this study, a total of 196 Campylobacter strains (125 isolates from humans, 39 from retail food and 32 from food animal sources) isolated in Portugal between 2009 and 2012 were characterised by multilocus sequence typing (MLST) and flaA short variable region (SVR) typing. Susceptibility to six antibiotics as well as the mechanisms underlying antibiotic resistance phenotypes was also studied. Based on MLST typing, C. coli strains were genetically more conserved, with a predominant clonal complex (CC828), than C. jejuni strains. In contrast, C. coli isolates were genetically more variable than C. jejuni with regard to flaA-SVR typing. A high rate of resistance was observed for quinolones (100% to nalidixic acid, >90% to ciprofloxacin) and, in general, resistance was more common among C. coli, especially for erythromycin (40.2% vs. 6.7%). In addition, most isolates (86%) were resistant to multiple antimicrobial families. Besides the expected point mutations associated with antibiotic resistance, detected polymorphisms in the cmeABC locus likely play a role in the multiresistant phenotype. This study provides for the first time an overview of the genetic diversity of Campylobacter strains from Portugal. It also shows a worrying antibiotic multiresistance rate and the emergence of Campylobacter strains resistant to antibiotics of human use.


Subject(s)
Campylobacter Infections/microbiology , Campylobacter Infections/veterinary , Campylobacter coli/classification , Campylobacter jejuni/classification , Drug Resistance, Bacterial , Food Microbiology , Genetic Variation , Adolescent , Adult , Aged , Anti-Bacterial Agents/pharmacology , Campylobacter coli/drug effects , Campylobacter coli/genetics , Campylobacter coli/isolation & purification , Campylobacter jejuni/drug effects , Campylobacter jejuni/genetics , Campylobacter jejuni/isolation & purification , Child , Child, Preschool , Cluster Analysis , Female , Flagellin/genetics , Genotype , Humans , Infant , Male , Microbial Sensitivity Tests , Middle Aged , Molecular Typing , Portugal , Young Adult
18.
Appl Microbiol Biotechnol ; 98(22): 9365-73, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25117549

ABSTRACT

Arabinoxylans (AX) consumption has been related to the treatment and prevention of cardiovascular diseases, type II diabetes, colorectal cancer and obesity. The beneficial health effects are conferred through gut microbiota modulation, and therefore, they have been proposed as potential slowly fermentable prebiotic candidates. As the mechanisms are not yet well understood, the prebiotic potential of AX from brewer's spent grain (BSG) has been investigated. Two types of AX from BSG (AX1 and AX2) of different length and branching averages were fermented with human faecal inocula and compared to fermented cultures containing a commercial prebiotic (fructooligosaccharide (FOS)) and cultures with no added carbohydrate (control). Results demonstrated that the AX were extensively metabolised after 48 h of fermentation. The pH decreased along fermentation and the lowest value was achieved in AX1 cultures. The production of short chain fatty acids (SCFA) was higher in AX cultures than in cultures containing FOS and controls, with AX1 presenting the highest concentrations. The stimulatory effect of beneficial bacteria was higher in AX cultures, and AX2 presented the highest positive effect. Prebiotic potential of AX from BSG was confirmed by the production of SCFA and the modulation of gut microbiota, especially by the high increase in bifidobacteria populations.


Subject(s)
Prebiotics , Xylans/metabolism , Bacteria/metabolism , Biota/drug effects , Fatty Acids/metabolism , Feces/microbiology , Fermentation , Humans , Hydrogen-Ion Concentration , Time Factors , Xylans/isolation & purification
19.
Int J Food Microbiol ; 180: 62-8, 2014 Jun 16.
Article in English | MEDLINE | ID: mdl-24786554

ABSTRACT

The frequent isolation of Arcobacter butzleri and Arcobacter cryaerophilus from food samples makes it imperative to search for potential compounds able to inhibit the development of these bacteria. Taking this into consideration, this study focuses on the antimicrobial activity of resveratrol and its mechanism of action against A. butzleri and A. cryaerophilus. The activity of resveratrol was assessed by a microdilution method and time-kill curves. Resveratrol effect on cellular functions was assessed by flow cytometry evaluating intracellular DNA content and metabolic activity. Ethidium bromide (EtBr) accumulation in the presence of resveratrol was also evaluated, as well as the susceptibility to resveratrol in the presence of phenylalanine-arginine ß-naphthylamide (PAßN). Scanning electron microscopy (SEM) was used to further evaluate cell damage caused by resveratrol. Resveratrol presented MIC values of 100 and 50µg/mL to A. butzleri and A. cryaerophilus, respectively. Based on the time-kill curves, resveratrol exhibited bactericidal activity, leading to a ≥3log10CFU/mL reduction of initial inoculums, for A. butzleri exponential phase cells incubated for 6h with 1× MIC or with 2× MIC after 24h for stationary phase cells. For A. cryaerophilus cells in exponential growth phase, 99.9% killing was achieved after 24h incubation with 2× MIC, whereas, for stationary phase cells, bactericidal activity was only detected after incubation with 4× MIC. Incubation with resveratrol led to a decrease in both intracellular DNA content and metabolic activity. An increase in the accumulation of EtBr was observed in the presence of resveratrol, and the efflux pump inhibitor PAßN reduced the MIC of resveratrol. SEM analysis revealed disintegration of A. butzleri cells treated with resveratrol, whereas no morphological alteration was observed for A. cryaerophilus cells. Resveratrol has a good anti-Arcobacter activity, and the results obtained suggest that this compound could act through several different mechanisms in the inhibition of this microorganism. The results encourage the use of this compound for the development of potential strategies to control Arcobacter in food products.


Subject(s)
Anti-Bacterial Agents/pharmacology , Arcobacter/drug effects , Food Microbiology , Stilbenes/pharmacology , DNA, Bacterial/analysis , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Resveratrol
20.
Diagn Microbiol Infect Dis ; 78(3): 220-5, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24361090

ABSTRACT

The present study was conducted to investigate the prevalence and diversity of Arcobacter and Campylobacter spp. in 298 stool samples of patients with diarrhoea, collected from 22 Portuguese hospitals, between September and November 2012. Detection of Arcobacter and Campylobacter spp. was performed using molecular-based detection techniques, such as real-time fluorescence resonance energy transfer PCR, species-specific PCR, and sequencing of amplified PCR products. Overall, 1.3% of the samples were positive for Arcobacter butzleri and 0.3% for Arcobacter cryaerophilus. Campylobacter spp. were found in 31.9% of diarrhoeic faeces. Campylobacter jejuni and Campylobacter concisus were the most prevalent species (13.7% and 8.0%, respectively). The prevalence of Arcobacter and Campylobacter spp. was significantly different between children and adults (39.7% versus 22.8%, P = 0.003). We underline the high prevalence of these pathogens in diarrhoeal samples among Portuguese patients, with particular relevance in the paediatric age group.


Subject(s)
Arcobacter/isolation & purification , Campylobacter/isolation & purification , DNA, Bacterial/isolation & purification , Diarrhea/microbiology , Real-Time Polymerase Chain Reaction/methods , Adolescent , Adult , Aged , Aged, 80 and over , Arcobacter/classification , Campylobacter/classification , Campylobacter Infections/diagnosis , Child , Child, Preschool , Feces/microbiology , Female , Gram-Negative Bacterial Infections/diagnosis , Humans , Infant , Infant, Newborn , Male , Middle Aged , Portugal , Sequence Analysis, DNA , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...