Microbiological, antioxidant and lipoxygenase-1 inhibitory activities of fruit extracts of chosen Rosaceae family species.

BACKGROUND: Extracts from the Rosaceae family fruits are rich in natural, biologically active polyphenols, but their antibacterial properties are still poorly understood. Therefore, we focused our research on their activity against uropathogenic Escherichia coli strains. This research also concerned the proof of their ability to reduce oxidative stress and modulate the activity of lipoxygenase-1 (LOX-1). It is well-known that plants represent a source of bioactive compounds whose antioxidant activity may be useful in protecting against oxidative damage in cells, which have been linked to the pathogenesis of many oxidative diseases. OBJECTIVES: The study determined the biological activity of methanol (ME) and water (WE) extracts rich in polyphenols from the hawthorn (Crataegus monogyna Jacq.), dog rose (Rosa canina L.), quince (Cydonia oblonga Mill.), and Japanese quince (Chaenomeles speciosa (Sweet) Nakai). MATERIAL AND METHODS: The antioxidant capacity was evaluated using 1,1diphenyl-2-picrylhydrazyl (DPPH▪) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS+▪) radical scavenging methods. The inhibition of liposome membrane oxidation was studied using the thiobarbituric acid reactive substances assay. Lipoxygenase-1 inhibitory activity was measured using the spectrophotometric method. Bacterial growth was determined by evaluating the number of colony forming units per milliliter (CFU/mL). Hydrophobicity was established with salt aggregation hydrophobicity test (SAT). Swimming and swarming motilities were evaluated using soft-agar plates. Production of curli fimbriae was estimated on CFA agar. The P fimbriae were detected using the hemagglutination of erythrocytes. Adhesion of bacteria to human uroepithelial cells was assessed. The amount of biofilm was determined spectrophotometrically. RESULTS: We showed that most of these extracts are effective antioxidants and free radical scavengers, possess reasonable potential anti-inflammatory activity, reduce the adhesion of E. coli to uroepithelial cells, and reduce the ability of these bacteria to form biofilm. CONCLUSIONS: The extracts examined, showing very promising biological properties, seem to be able to join the list of substances that can be used as dietary supplements aimed at preventing, for example, urinary tract infections, or as support of drug treatment in many diseases.

Biological activity of the methanol and water extracts of the fruits of anthocyanin-rich plants grown in south-west Poland.

In this study we focused on the chemical composition, antioxidant, anti-inflammatory and antibacterial properties of methanol and water extracts of fruits of six species grown in south-west Poland: blackberry, blackcurrant, chokeberry, cherry, gooseberry and raspberry. No general correlation could be drawn between extract chemical properties (i.e. antioxidant and free radical scavenging) and observed biological effects. However, blackcurrant and blackberry extracts (both methanol and water) appeared to be good antioxidants and free radical scavengers, as well as effective inhibitors of E. coli adhesion to the uroepithelial cells. On the other hand, the poorest antioxidants and free radical scavengers, cherry and gooseberry extracts, also poorly affected bacterial growth, swimming ability and adhesion to epithelial cells. Surprisingly, gooseberry extracts, which showed generally weak effects, appearedto be the most effective inhibitor of bacterial biofilm formation. Additionally, most of the studied extracts showed reasonably strong anti-inflammatory properties.

Analysis of the SDS-PAGE patterns of outer membrane proteins from Escherichia coli strains that have lost the ability to form K1 antigen and varied in the susceptibility to normal human serum.

We used SDS-polyacrylamide gel electrophoresis to investigate the outer membrane proteins (OMPs) band composition of 19 Escherichia coli K1 strains that have spontaneously lost the ability to form K1 polysaccharide capsule (E. coli K1-) and demonstrated different degrees of susceptibility to the bactericidal action of normal human serum. Presented results showed that there were differences between E. coli K1- strains in OMPs expressing capacity. The analysis performed on OMPs has not revealed a direct association between the different OMPs band composition and the susceptibility of these strains to the serum.

The bactericidal activity of normal human serum against Enterobacteriaceae rods with lipopolysaccharides possessing O-antigens composed of mannan.

BACKGROUND: The susceptibility of bacteria to the bactericidal activity of serum depends on the structure and organization of the bacterial outer membrane. It is known that the structure of the O-specific polysaccharide chain of lipopolysaccharide (LPS) plays an important role in the resistance of bacteria to host immune defenses. OBJECTIVES: The susceptibility of rods belonging to Enterobacteriaceae family to the bactericidal activity of the normal human serum (NHS) was examined. The mechanisms of complement activation were also investigated. MATERIAL AND METHODS: The study was carried out on 15 strains containing LPSs with O-specific polysaccharides composed of mannan, belonging to the following species: Citrobacter freundii, C. werkmanii, C. braakii, C. youngae, Hafnia alvei, Escherichia coli and Klebsiella pneumoniae. The levels of C3 and C4 complement components, IgG and IgM immunoglobulin in NHS were examined using specific antibodies. The bactericidal activity of NHS and its preparations (HS50/20, HSMgEGTA) was determined. LPSs from E. coli 08 strains were analyzed by polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulphate (SDS). RESULTS: Eleven strains were sensitive to NHS bactericidal activity, and four were resistant. Only one group of strains was fully susceptible to NHS action. In three other groups, both sensitive and resistant strains were found. The majority of the strains remained susceptible to NHS activity irrespective of which pathway of serum activity was blocked. All E. coli 08 strains contained smooth-type LPSs. CONCLUSIONS: Strains belonging to the same serotype showed variable susceptibility to the bactericidal action of normal human serum. Two mechanisms of the bactericidal activity of NHS have been identified.

Anthocyanins as antimicrobial agents of natural plant origin.

Anthocyanins are particularly abundant in different fruits, especially in berries. The beneficial effects of these compounds for human health have been known from at least the 16th century. Despite the great number of papers devoted to the different biological effects exerted by anthocyanins only a limited number of studies is focused on the antimicrobial activity of these compounds. Anthocyanin content of berry fruits varies from 7.5 mg/100 mg fresh fruit in redcurrant (Ribes rubum) up to 460 mg/100 g fresh fruit in chokeberry (Aronia melanocarpa). After consumption, anthocyanins are intensively metabolized, mainly in the intestines and liver. Glucorination, methylation and sulfation are the most typical metabolic reactions. Antimicrobial activity of crude extracts of plant phenolic compounds against human pathogens has been intensively studied to characterize and develop new healthy food ingredients as well as medical and pharmaceutical products. However, there is very little information available about the antimicrobial activity of the pure anthocyanins. In the last part of this review we present the collection of papers describing the anthocyanin profiles of different fruits (mainly berries) and the antimicrobial properties of the identified compounds. Generally, anthocyanins are active against different microbes, however Gram-positive bacteria usually are more susceptible to the anthocyanin action than Gram-negative ones. Mechanisms underlying anthocyanin activity include both membrane and intracellular interactions of these compounds. Antimicrobial activity of berries and other anthocyanin-containing fruits is likely to be caused by multiple mechanisms and synergies because they contain various compounds including anthocyanins, weak organic acids, phenolic acids, and their mixtures of different chemical forms. Therefore, the antimicrobial effect of chemically complex compounds has to be critically analyzed.

The effect of using whole wheat grain in the diet of game pheasants on their body weight, dimensions and development of some internal organs.

The supplementation of game pheasant diet from 5 weeks of age with 30% whole wheat grain instead of feed mixture did not significantly affect their body weight nor most body dimensions. Female and male pheasants fed a diet containing wheat grain had smaller body and trunk lengths, greater chest circumference and greater length of breastbone, and lower thigh and shank size. Female pheasants were characterized by higher indices of compactness and long-leggedness, whereas male pheasants had higher indices of massiveness, compactness and long-leggedness than pheasants fed only feed mixtures. Cock pheasants receiving the wheat diet also had a statistically shorter trunk, however, hens possessed a statistically longer lower thigh. Length of intestine (174.2 cm) and individual parts of the intestine (small intestine 119.9 cm; caeca 43 cm; rectum 11.3 cm) was greater in cocks fed whole wheat grain compared to cocks receiving only feed mixtures (156.1; 107.6; 38.8; 9.7 cm, respectively). An opposite cocks was found in hens. Supplementation of whole wheat grain in the diets significantly (P < or = 0.05) increased liver weight and percentage in females and significantly decreased testicular weight and percentage in males. It was also found that females of both feed-treatment groups had significantly lower weights ofheart, liver and spleen, and hens fed only feed mixtures were also characterized by a significantly lower weight of the proventriculus.

Sialic acid-containing lipopolysaccharides of Salmonella O48 strains--potential role in camouflage and susceptibility to the bactericidal effect of normal human serum.

Sialic acid (N-acetylneuraminic acid, NeuAc) plays an essential role in protecting gram-negative bacteria against the bactericidal activity of serum and may contribute to the pathogenicity of bacteria by mimicking epitopes that resemble host tissue components (molecular mimicry). The role of sialic acid (NeuAc)-containing lipopolysaccharides (LPS) of Salmonella O48 strains in the complement activation of normal human serum (NHS) was investigated. NeuAc-containing lipooligosaccharides cause a downregulation of complement activation and may serve to camouflage the bacterial surface from the immunological response of the host. Serotype O48 Salmonella strains have the O-antigen structure containing NeuAc while its serovars differ in outer membrane protein composition. In this study, the mechanisms of complement activation responsible for killing Salmonella O48 serum-sensitive rods by NHS were established. Four of such mechanisms involving pathways, which are important in the bactericidal mechanism of complement activation, were distinguished: only the classical/lectin pathways, independent activation of the classical/lectin or alternative pathway, parallel activation of the classical/lectin and alternative pathways, and only the alternative pathway important in the bactericidal action of human serum. To further study the role of NeuAc, its content in bacterial cells was determined by gas-liquid chromatography-mass spectrometry in relation to 3-deoxy-D-manno-2-octulosonic acid (Kdo), an inherent constituent of LPS. The results indicate that neither the presence of sialic acid in LPS nor the length of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal activity of complement and that the presence of sialic acid in the structure of LPS is not sufficient to block the activation of the alternative pathway of complement. We observed that for three strains with a very high NeuAc/Kdo ratio the alternative pathways were decisive in the bactericidal action of human serum. The results indicated that those strains are not capable of inhibiting the alternative pathway very effectively. As the pathogenicity of most Salmonella serotypes remains undefined, research into the interactions between these bacterial cells and host organisms is indispensable.

Composition of the outer membrane proteins of Escherichia coli strains in relation to serum susceptibility after exposure to subinhibitory concentrations of amikacin and ciprofloxacin.

The effect of subinhibitory concentrations of amikacin and ciprofloxacin on the susceptibility of Escherichia coli strains to the bactericidal action of normal human serum, outer membrane protein (OMP) expression and cell morphology was investigated. Sub-minimal inhibitory concentrations (sub-MICs) of both antibiotics were found to alter the expression of some OMPs of serum-resistant E. coli rods, the morphology of their cells and made them sensitive to the bactericidal activity of normal human serum.

[Bactericidal action of human serum against Pseudomonas aeruginosa strains with hydrophilic or hydrophobic cell surface]. / Bakteriobójcza aktywnosc surowicy ludzkiej wobec paleczek Pseudomonas aeruginosa charakteryzujacych sie hydrofilna lub hydrofobowa powierzchnia, komórek.

Pseudomonas aeruginosa strains are the prominent nosocomial pathogens, especially dangerous for patients hospitalized in intensive care units. The cell surface hydrophobicity of P. aeruginosa rods and resistance to the bactericidal action of serum are considered as important factors of their virulence. The aim of the study was to evaluate the susceptibility of hydrophilic and hydrophobic P aeruginosa strains to the bactericidal effect of human serum. These strains were isolated from bronchioloalveolar lavage of children with hospital-acquired pneumonia. The BATH test was used to evaluate the hydrophobic properties. Among tested P aeruginosa strains seven had strong hydrophobic properties and eight strains were hydrophilic. The data showed that hydrophobic strains were more frequently serum-resistant than rods with hydrophilic cell surface.

[Evaluation of sensitivity to antibiotics of microorganisms isolated from children with urinary tract infections]. / Ocena wrazliwosci na antybiotyki drobnoustrojów wyizolowanych od dzieci chorych na zakazenia ukladu moczowego.

The incidence of etiological factors of urinary tract infections in children and in vitro susceptibility of these strains to antibiotics were evaluated. 1082 strains isolated from 905 samples of urine of children hospitalized in the period of 01.01-31.12.2001 were tested. Among the isolated microorganisms, the most common group was the Enterobacteriaceae family (57.4%) and also very often Gram-positive cocci were isolated (34.2%). The most frequent causative agents of UTI (Escherichia coli and Enterococcus faecalis) were generally sensitive to all used antibiotics, but E. coli rods were resistant to ampicillin. In addition, 23.4% of E. coli were the ESBL-producing strains.