Direct adhesion force measurements between E. coli and human uroepithelial cells in cranberry juice cocktail

Crack patterns of drying dense bacterial suspensions

Drying of bacterial suspensions is frequently encountered in a plethora of natural and engineering processes. However, the evaporation-driven mechanical instabilities of dense consolidating bacterial suspensions have not been explored heretofore. Here, we report the formation of two different crack patterns of drying suspensions of Escherichia coli (E. coli) with distinct motile behaviors. Circular cracks are observed for wild-type E. coli with active swimming, whereas spiral-like cracks form for immotile bacteria. Using the elastic fracture mechanics and the poroelastic theory, we show that the formation of the circular cracks is determined by the tensile nature of the radial drying stress once the cracks are initiated by the local order structure of bacteria due to their collective swimming. Our study demonstrates the link between the microscopic swimming behaviors of individual bacteria and the mechanical instabilities and macroscopic pattern formation of drying bacterial films. The results shed light on the dynamics of active matter in a drying process and provide useful information for understanding various biological processes associated with drying bacterial suspensions.

Quantifying molecular- to cellular-level forces in living cells

Mechanical cues have been suggested to play an important role in cell functions and cell fate determination, however, such physical quantities are challenging to directly measure in living cells with single molecule sensitivity and resolution. In this review, we focus on two main technologies that are promising in probing forces at the single molecule level. We review their theoretical fundamentals, recent technical advancements, and future directions, tailored specifically for interrogating mechanosensitive molecules in live cells.

Binding Strength of Gram-Positive Bacterial Adhesins

Bacterial pathogens are equipped with specialized surface-exposed proteins that bind strongly to ligands on host tissues and biomaterials. These adhesins play critical roles during infection, especially during the early step of adhesion where the cells are exposed to physical stress. Recent single-molecule experiments have shown that staphylococci interact with their ligands through a wide diversity of mechanosensitive molecular mechanisms. Adhesin-ligand interactions are activated by tensile force and can be ten times stronger than classical non-covalent biological bonds. Overall these studies demonstrate that Gram-positive adhesins feature unusual stress-dependent molecular interactions, which play essential roles during bacterial colonization and dissemination. With an increasing prevalence of multidrug resistant infections caused by Staphylococcus aureus and Staphylococcus epidermidis, chemotherapeutic targeting of adhesins offers an innovative alternative to antibiotics.

How Microbes Use Force To Control Adhesion

Microbial adhesion and biofilm formation are usually studied using molecular and cellular biology assays, optical and electron microscopy, or laminar flow chamber experiments. Today, atomic force microscopy (AFM) represents a valuable addition to these approaches, enabling the measurement of forces involved in microbial adhesion at the single-molecule level. In this minireview, we discuss recent discoveries made applying state-of-the-art AFM techniques to microbial specimens in order to understand the strength and dynamics of adhesive interactions. These studies shed new light on the molecular mechanisms of adhesion and demonstrate an intimate relationship between force and function in microbial adhesins.

What makes bacterial pathogens so sticky?

Pathogenic bacteria use a variety of cell surface adhesins to promote binding to host tissues and protein-coated biomaterials, as well as cell-cell aggregation. These cellular interactions represent the first essential step that leads to host colonization and infection. Atomic force microscopy (AFM) has greatly contributed to increase our understanding of the specific interactions at play during microbial adhesion, down to the single-molecule level. A key asset of AFM is that adhesive interactions are studied under mechanical force, which is highly relevant as surface-attached pathogens are often exposed to physical stresses in the human body. These studies have identified sophisticated binding mechanisms in adhesins, which represent promising new targets for antiadhesion therapy.

Using Atomic Force Microscopy To Illuminate the Biophysical Properties of Microbes

Since its invention in 1986, atomic force microscopy (AFM) has grown from a system designed for imaging inorganic surfaces to a tool used to probe the biophysical properties of living cells and tissues. AFM is a scanning probe technique and uses a pyramidal tip attached to a flexible cantilever to scan across a surface, producing a highly detailed image. While many research articles include AFM images, fewer include force-distance curves, from which several biophysical properties can be determined. In a single force-distance curve, the cantilever is lowered and raised from the surface, while the forces between the tip and the surface are monitored. Modern AFM has a wide variety of applications, but this review will focus on exploring the mechanobiology of microbes, which we believe is of particular interest to those studying biomaterials. We briefly discuss experimental design as well as different ways of extracting meaningful values related to cell surface elasticity, cell stiffness, and cell adhesion from force-distance curves. We also highlight both classic and recent experiments using AFM to illuminate microbial biophysical properties.

Molecular Mechanisms That Define Redox Balance Function in Pathogen-Host Interactions-Is There a Role for Dietary Bioactive Polyphenols?

To ensure a functional immune system, the mammalian host must detect and respond to the presence of pathogenic bacteria during infection. This is accomplished in part by generating reactive oxygen species (ROS) that target invading bacteria; a process that is facilitated by NADPH oxidase upregulation. Thus, bacterial pathogens must overcome the oxidative burst produced by the host innate immune cells in order to survive and proliferate. In this way, pathogenic bacteria develop virulence, which is related to the affinity to secrete effector proteins against host ROS in order to facilitate microbial survival in the host cell. These effectors scavenge the host generated ROS directly, or alternatively, manipulate host cell signaling mechanisms designed to benefit pathogen survival. The redox-balance of the host is important for the regulation of cell signaling activities that include mitogen-activated protein kinase (MAPK), p21-activated kinase (PAK), phosphatidylinositol 3-kinase (PI3K)/Akt, and nuclear factor κB (NF-κB) pathways. An understanding of the function of pathogenic effectors to divert host cell signaling is important to ascertain the mechanisms underlying pathogen virulence and the eventual host–pathogen relationship. Herein, we examine the effectors produced by the microbial secretion system, placing emphasis on how they target molecular signaling mechanisms involved in a host immune response. Moreover, we discuss the potential impact of bioactive polyphenols in modulating these molecular interactions that will ultimately influence pathogen virulence.

A review on anti-adhesion therapies of bacterial diseases

BACKGROUND

Infections caused by bacteria are a foremost cause of morbidity and mortality in the world. The common strategy of treating bacterial infections is by local or systemic administration of antimicrobial agents. Currently, the increasing antibiotic resistance is a serious and global problem. Since the most important agent for infection is bacteria attaching to host cells, hence, new techniques and attractive approaches that interfere with the ability of the bacteria to adhere to tissues of the host or detach them from the tissues at the early stages of infection are good therapeutic strategies.

METHODS

All available national and international databanks were searched using the search keywords. Here, we review various approaches to anti-adhesion therapy, including use of receptor and adhesion analogs, dietary constituents, sublethal concentrations of antibiotics, and adhesion-based vaccines.

RESULTS

Altogether, the findings suggest that interference with bacterial adhesion serves as a new means to fight infectious diseases.

CONCLUSION

Anti-adhesion-based therapies can be effective in prevention and treatment of bacterial infections, but further work is needed to elucidate underlying mechanisms.

Innovative Solutions to Sticky Situations: Antiadhesive Strategies for Treating Bacterial Infections

Bacterial adherence to host tissue is an essential process in pathogenesis, necessary for invasion and colonization and often required for the efficient delivery of toxins and other bacterial effectors. As existing treatment options for common bacterial infections dwindle, we find ourselves rapidly approaching a tipping point in our confrontation with antibiotic-resistant strains and in desperate need of new treatment options. Bacterial strains defective in adherence are typically avirulent and unable to cause infection in animal models. The importance of this initial binding event in the pathogenic cascade highlights its potential as a novel therapeutic target. This article seeks to highlight a variety of strategies being employed to treat and prevent infection by targeting the mechanisms of bacterial adhesion. Advancements in this area include the development of novel antivirulence therapies using small molecules, vaccines, and peptides to target a variety of bacterial infections. These therapies target bacterial adhesion through a number of mechanisms, including inhibition of pathogen receptor biogenesis, competition-based strategies with receptor and adhesin analogs, and the inhibition of binding through neutralizing antibodies. While this article is not an exhaustive description of every advancement in the field, we hope it will highlight several promising examples of the therapeutic potential of antiadhesive strategies.

Escherichia coli removal from model substrates: Underlying mechanism based on nanofluid structural forces

Understanding the interactions between bacteria and solid surfaces that result in bacterial adhesion and removal is of immense importance for reducing foodborne illness outbreaks. A nanofluid formulation comprised of a sodium dodecyl sulfate (SDS) micellar aqueous solution in the presence of an organic acid (as a pH controller) was used to test the E. coli K12 removal from two substrates, polyvinylchloride (PVC) and partially hydrophobic glass. We investigated the bacterial removal efficacy based on the combined effect of the nanofluid's structural forces and bacterial isoelectric point. To quantify the bacteria-PVC coverage, we used fluorescence microscope. The Langmuir isotherm at the low volume fraction was applied to estimate the adsorption energy of E. coli K12. We obtained a value of about 2.5±0.2kT. This value compared favorably with the value of 2.1kT reported previously for E. coli NCTC 9002 (Vanloosdrecht et al., 1989). We applied the dynamic light scattering method to estimate the radius of the gyration of E. coli K12. The radius of the gyration was used to estimate the limit of surface area covered by the bacterium and compared it to the surface area measured from the image taken with fluorescence microscope. We found that they are in good agreement with each other. We modeled the nanofluid oscillatory structural energy against the E. coli K12 adsorption energy by applying the statistical mechanics approach. Based on the model prediction, the oscillatory interaction energy was estimated at the vertex between a bacterium and the substrate (i.e., the wedge film's interaction energy at one particle layer). The evaluated film's repulsive energy due to the oscillatory structural forces (OSF) was about 15.6±4.4kT of the 0.02M SMNF (the SDS micellar nanofluid formulation) and several times higher than the bacterial adsorption energy, 2.5±0.2kT. The OSF of the 0.06M SMNF was measured by AFM (the oscillatory decay force curve). The period and number of oscillations versus distance was annualized and used to obtain information for the effective size of the nanoparticles and nanofluid's effective volume fraction. These findings suggest that the OSF is capable of bacteria/microorganism removal from contaminated substrates.

Direct mapping of melanoma cell - endothelial cell interactions

The most life-threatening aspect of cancer is metastasis; cancer patient mortality is mainly due to metastasis. Among all metastases, presence of brain metastasis is one with the poorest prognosis; the median survival time can be counted in months. Therefore, prevention or decreasing their incidence would be highly desired both by patients and physicians. Metastatic cells invading the brain must breach the cerebral vasculature, primarily the blood-brain barrier. The key step in this process is the establishment of firm adhesion between the cancer cell and the cerebral endothelial layer. Using the atomic force microscope, a high-resolution force spectrograph, our aim was to explore the connections among the cell morphology, cellular mechanics, and biological function in the process of transendothelial migration of metastatic cancer cells. By immobilization of a melanoma cell to an atomic force microscope's cantilever, intercellular adhesion was directly measured at quasi-physiological conditions. Hereby, we present our latest results by using this melanoma-decorated probe. Binding characteristics to a confluent layer of brain endothelial cells was directly measured by means of single-cell force spectroscopy. Adhesion dynamics and strength were characterized, and we present data about spatial distribution of elasticity and detachment strength. These results highlight the importance of cellular mechanics in brain metastasis formation and emphasize the enormous potential toward exploration of intercellular dynamic-related processes.

Lactobacilli require physical contact to reduce staphylococcal TSST-1 secretion and vaginal epithelial inflammatory response

ITALIC! Staphylococcus aureusbiofilms can be found on vaginal epithelia, secreting toxins and causing inflammation. The co-vaginal species ITALIC! Lactobacilluscan alter staphylococcal-induced epithelial secretion of inflammatory cytokines and quench staphylococcal toxic shock syndrome toxin-1 secretion. It is hypothesized that these effects of lactobacilli require direct physical contact between lactobacilli, staphylococci and the epithelium. Indeed, lactobacilli only reduced ITALIC! S. aureus-induced inflammatory cytokine expression when allowed physical contact with vaginal epithelial cells. Furthermore, a reduction in toxic shock syndrome toxin-1 secretion only occurred when a probiotic ITALIC! Lactobacillusstrain was allowed contact, but not when being physically separated from ITALIC! S. aureus Bacterial-probe atomic force microscopy demonstrated that lactobacilli and staphylococci strongly adhere to epithelial cells, while lactobacilli adhere stronger to staphylococci than staphylococci to each other, giving lactobacilli opportunity to penetrate and reside in staphylococcal biofilms, as visualized using confocal laser scanning microscopy with fluorescence ITALIC! in situhybridization probes. These results identify that physical contact and biochemical signaling by lactobacilli are intrinsically linked mechanisms that reduce virulence of ITALIC! S. aureusbiofilm.

Nanoscale characteristics of antibacterial cationic polymeric brushes and single bacterium interactions probed by force microscopy

A direct probing technique was applied to PEI brushes to investigate bacteria–PEI brush interactions in a single bacterium resolution.

Atomic force microscopy-guided fractionation reveals the influence of cranberry phytochemicals on adhesion of Escherichia coli

Characterization of cranberry juice fractions for their role in anti-adhesive properties against pathogenicE. coliusing Atomic Force Microscopy (AFM).

AFM-based force spectroscopy for bioimaging and biosensing

AFM-based force spectroscopy shows wide bio-related applications especially for bioimaging and biosensing.

Forces guiding staphylococcal adhesion

Staphylococcus epidermidis and Staphylococcus aureus are two important nosocomial pathogens that form biofilms on indwelling medical devices. Biofilm infections are difficult to fight as cells within the biofilm show increased resistance to antibiotics. Our understanding of the molecular interactions driving bacterial adhesion, the first stage of biofilm formation, has long been hampered by the paucity of appropriate force-measuring techniques. In this minireview, we discuss how atomic force microscopy techniques have enabled to shed light on the molecular forces at play during staphylococcal adhesion. Specific highlights include the study of the binding mechanisms of adhesion molecules by means of single-molecule force spectroscopy, the measurement of the forces involved in whole cell interactions using single-cell force spectroscopy, and the probing of the nanobiophysical properties of living bacteria via multiparametric imaging. Collectively, these findings emphasize the notion that force and function are tightly connected in staphylococcal adhesion.

Vaginal epithelial cells regulate membrane adhesiveness to co-ordinate bacterial adhesion

Vaginal epithelium is colonized by different bacterial strains and species. The bacterial composition of vaginal biofilms controls the balance between health and disease. Little is known about the relative contribution of the epithelial and bacterial cell surfaces to bacterial adhesion and whether and how adhesion is regulated over cell membrane regions. Here, we show that bacterial adhesion forces with cell membrane regions not located above the nucleus are stronger than with regions above the nucleus both for vaginal pathogens and different commensal and probiotic lactobacillus strains involved in health. Importantly, adhesion force ratios over membrane regions away from and above the nucleus coincided with the ratios between numbers of adhering bacteria over both regions. Bacterial adhesion forces were dramatically decreased by depleting the epithelial cell membrane of cholesterol or sub-membrane cortical actin. Thus, epithelial cells can regulate membrane regions to which bacterial adhesion is discouraged, possibly to protect the nucleus.

Cranberry and recurrent cystitis: more than marketing?

Epidemiologic studies indicate that millions of people suffer from recurrent cystitis, a pathology requiring antibiotic prophylaxis and entailing high social costs. Cranberry is a traditional folk remedy for cystitis and, which, in the form of a variety of products and formulations has over several decades undergone extensive evaluation for the management of urinary tract infections (UTI). The aim of this retrospective study is to summarize and review the most relevant and recent preclinical and clinical studies on cranberries for the treatment of UTIs. The scientific literature selected for this review was identified by searches of Medline via PubMed. A variety of recent experimental evidence has shed light on the mechanism underlying the anti-adhesive properties of proanthrocyanidins, their structure-activity relationships, and pharmacokinetics. Analysis of clinical studies and evaluation of the cranberry efficacy/safety ratio in the prevention of UTIs strongly support the use of cranberry in the prophylaxis of recurrent UTIs in young and middle-aged women. However, evidence of its clinical use among other patients remains controversial.

Atomic force microscopy in microbiology: new structural and functional insights into the microbial cell surface

Microbial cells sense and respond to their environment using their surface constituents. Therefore, understanding the assembly and biophysical properties of cell surface molecules is an important research topic. With its ability to observe living microbial cells at nanometer resolution and to manipulate single-cell surface molecules, atomic force microscopy (AFM) has emerged as a powerful tool in microbiology. Here, we survey major breakthroughs made in cell surface microbiology using AFM techniques, emphasizing the most recent structural and functional insights.

Fluorescent labeling of cranberry proanthocyanidins with 5-([4,6-dichlorotriazin-2-yl]amino)fluorescein (DTAF)

A novel methodology was developed to elucidate proanthocyanidins (PAC) interaction with extra-intestinal pathogenic Escherichia coli (ExPEC). PAC inhibit ExPEC invasion of epithelial cells and, therefore, may prevent transient gut colonization, conferring protection against subsequent extra-intestinal infections, such as urinary tract infections. Until now PAC have not been chemically labeled with fluorophores. In this work, cranberry PAC were labeled with 5-([4,6-dichlorotriazin-2-yl]amino) fluorescein (DTAF), detected by high-performance liquid chromatography with diode-array detection and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). We report single and double fluorescent-labeled PAC with one or two chlorine atoms displaced from DTAF in alkaline pH via nucleophilic substitution. Fluorescent labeling was confirmed by fragmentation experiments using MALDI-TOF/TOF MS. Fluorescent labeled PAC were able to promote ExPEC agglutination when observed with fluorescence microscopy. DTAF tagged PAC may be used to trace the fate of PAC after they agglutinate ExPEC and follow PAC-ExPEC complexes in cell culture assays.

Impact of behaviour and lifestyle on bladder health

Bladder conditions, including UTI, UI, and bladder cancer, are highly prevalent and affect a wide range of populations. There are a variety of modifiable behavioral and lifestyle factors that influence bladder health. Some factors, such as smoking and obesity, increase the risk or severity of bladder conditions, whereas other factors, such as pelvic floor muscle exercise, are protective. Although clinical practice may be assumed to be the most appropriate ground for education on behavioral and lifestyle factors that influence bladder health, it is also crucial to extend these messages into the general population through public health interventions to reach those who have not yet developed bladder conditions and to maximize the prevention impact of these behaviors. Appropriate changes in these factors have the potential for an enormous impact on bladder health if implemented on a population-based level.

Anti-adhesion methods as novel therapeutics for bacterial infections

Anti-adhesion therapies for bacterial infections offer an alternative to antibiotics, with those therapies bacteria are not killed but are prevented from causing harm to a host by inhibiting adherence to host cells and tissues, a prerequisite for the majority of infectious diseases. The mechanisms of these potential therapeutic agents include inhibition of adhesins and their host receptors, vaccination with adhesins or analogs, use of probiotics and dietary supplements that interfere with receptor-adhesin interactions, subminimal inhibitory concentrations of antibiotics and manipulation of hydrophobic interactions. Once developed, these drugs will contribute to the arsenal for fighting infectious disease in the future, potentially subverting antibiotic resistance.

Surface thermodynamic and adhesion force evaluation of the role of chitin-binding protein in the physical interaction between Pseudomonas aeruginosa and Candida albicans

Candida albicans and Pseudomonas aeruginosa are able to form pathogenic polymicrobial communities. P. aeruginosa colonizes and kills hyphae but is unable to attach to yeast. It is unknown why the interaction of P. aeruginosa is different with yeast than with hyphae. Here we aim to evaluate the role of P. aeruginosa chitin-binding protein (CbpD) in its physical interaction with C. albicans hyphae or yeast, based on surface thermodynamic and atomic force microscopic analyses. A P. aeruginosa mutant lacking CbpD was unable to express strong adhesion forces with hyphae (-2.9 nN) as compared with the parent strain P. aeruginosa PAO1 (-4.8 nN) and showed less adhesion to hyphae. Also blocking of CbpD using N-acetyl-glucosamine yielded a lower adhesion force (-4.3 nN) with hyphae. Strong adhesion forces were restored after complementing the expression of CbpD in P. aeruginosa PAO1 ΔcbpD yielding an adhesion force of -5.1 nN. These observations were confirmed with microscopic evaluation of adhesion tests. Regardless of the absence or presence of CbpD on the bacterial cell surfaces, or their blocking, P. aeruginosa experienced favorable thermodynamic conditions for adhesion with hyphae, which were absent with yeast. In addition, adhesion forces with yeast were less than 0.5 nN in all cases. Concluding, CbpD in P. aeruginosa is responsible for strong physical interactions with C. albicans hyphae. The development of this interaction requires time due to the fact that CbpDs have to invade the outermost mannoprotein layer on the hyphal cell surfaces. In order to do this, thermodynamic conditions at the outermost cell surfaces have to be favorable.

Urine post equivalent daily cranberry juice consumption may opsonize uropathogenicity of Escherichia coli

Basic studies have proven that cranberries may prevent urinary tract infections through changing the adhesiveness of Escherichia coli (E. coli) to urothelial cells. Various cranberry preparations, including extract powder, capsules, and juice, have been shown to be effective in clinical and epidemiological research. Because cranberries are most commonly consumed as juice in a diluted concentration, the aim of this study was to investigate whether the equivalent daily dose of cranberry juice is sufficient to modify host urine to change the uropathogenicity of E. coli. Urine from rats taking an equivalent daily dose of cranberry juice has been shown to decrease the capability of E. coli in hemagglutination, urothelium adhesion, nematode killing, and biofilm formation. All these changes occurred after E. coli was incubated in cranberry metabolite-containing urine, defined as urine opsonization. Urine opsonization of E. coli resulted in 40.9% (p = 0.0038) decrease in hemagglutination ability, 66.7% (p = 0.0181) decrease in urothelium adhesiveness, 16.7% (p = 0.0004) increase in the 50% lethal time in killing nematodes, and 53.9% (p = 5.9 × 10(-4)) decrease in biofilm formation. Thus, an equivalent daily dose of cranberry juice should be considered sufficiently potent to demonstrate urine opsonization in E. coli.

Effects of cranberry components on human aggressive periodontitis gingival fibroblasts

BACKGROUND AND OBJECTIVE

Aggressive periodontitis (AgP) causes rapid periodontal breakdown involving AgP gingival fibroblast production of cytokines [i.e. interleukin (IL)-6, a bone metabolism regulator], and matrix metalloproteinase (MMP)-3. Lipopolysaccharide upregulates fibroblast IL-6 and MMP-3, via transcription factors (i.e. NF-κB). Cranberry (Vaccinium macrocarpon) inhibits lipopolysaccharide-stimulated macrophage and normal gingival fibroblast activities, but little is known of its effects on AgP fibroblasts. Objectives of this study are to use AgP fibroblasts, to determine cytotoxicity of cranberry components or periodontopathogen (Fusobacterium nucleatum, Porphyromonas gingivalis) lipopolysaccharide ± cranberry components, and effects of cranberry components on lipopolysaccharide-stimulated NF-κB activation and IL-6 and MMP-3 production.

MATERIAL AND METHODS

AgP fibroblasts were incubated ≤ 6 d with high molecular weight non-dialyzable material (NDM) (derived from cranberry juice (1-500 μg/mL) or lipopolysaccharide (1 μg/mL) ± NDM. Membrane damage and viability were assessed by enzyme activity released into cell supernatants and activity of a mitochondrial enzyme, respectively. Secreted IL-6 and MMP-3 were measured by ELISA. NF-κB p65 was measured via binding to an oligonucleotide containing the NF-κB consensus site. Data were analyzed using analysis of variance and Scheffe's F procedure for post hoc comparisons.

RESULTS

Short-term exposure to NDM, or lipopolysaccharide ± NDM caused no membrane damage. NDM (≤ 100 μg/mL) or lipopolysaccharide ± NDM had no effect on viability ≤ 7 d exposure. NDM (50 μg/mL) inhibited lipopolysaccharide-stimulated p65 (P ≤ 0.003) and constitutive or lipopolysaccharide-stimulated MMP-3 (P ≤ 0.02). NDM increased AgP fibroblast constitutive or lipopolysaccharide-stimulated IL-6 (P ≤ 0.0001), but inhibited normal human gingival fibroblast IL-6 (P ≤ 0.01).

CONCLUSION

Lack of toxicity of low NDM concentrations, and its inhibition of NF-κB and MMP-3, suggest that cranberry components may regulate AgP fibroblast inflammatory responses. Distinct effects of NDM on AgP and gingival fibroblast production of IL-6 (which can have both positive and negative effects on bone metabolism) may reflect phenotypic differences in IL-6 regulation in the two cell types.

Cranberry components for the therapy of infectious disease

Summary of the in vitro data support a beneficial effect of cranberry or its proanthocyanin constituents by blocking adhesion to and biofilm formation on target tissues of pathogens. In vivo data partially support these beneficial effects. Consumption of various cranberry products benefited young and elderly females in preventing urinary tract infections, and in conjunction with antibiotic treatment in eradicating Helicobacter pylori infections in women. Mouthwash supplemented with an isolated cranberry derivative reduced significantly the caryogenic mutans streptococci. None of the mice infected intranasal with lethal dose of influenza virus and treated with cranberry fraction died after two weeks. Further studies should focus on the active cranberry component as supplement for food and other products especially where whole juice or powder cannot be used.

CsgA production by Escherichia coli O157:H7 alters attachment to abiotic surfaces in some growth environments

The role of curli expression in attachment of Escherichia coli O157:H7 to glass, Teflon, and stainless steel (SS) was investigated through the creation of csgA knockout mutants in two isolates of E. coli O157:H7. Attachment assays using epifluorescence microscopy and measurements of the force of adhesion of bacterial cells to the substrates using atomic force microscopy (AFM) force mapping were used to determine differences in attachment between wild-type (wt) and csgA-negative (ΔcsgA) strains following growth in four different media. The hydrophobicity of the cells was determined using contact angle measurements (CAM) and bacterial adhesion to hydrocarbons (BATH). The attachment assay results indicated that ΔcsgA strains attached to glass, Teflon, and SS surfaces in significantly different numbers than their wt counterparts in a growth medium-dependent fashion (P < 0.05). However, no clear correlation was seen between attachment numbers, surface type, or growth medium. No correlation was seen between BATH and CAM results (R(2) < 0.70). Hydrophobicity differed between the wt and ΔcsgA in some cases in a growth medium- and method-dependent fashion (P < 0.05). AFM force mapping revealed no significant difference in the forces of adhesion to glass and SS surfaces between wt and ΔcsgA strains (P > 0.05) but a significantly greater force of adhesion to Teflon for one of the two wt strains than for its ΔcsgA counterpart (P < 0.05). This study shows that CsgA production by E. coli O157:H7 may alter attachment behavior in some environments; however, further investigation is required in order to determine the exact relationship between CsgA production and attachment to abiotic surfaces.

Determination of cranberry phenolic metabolites in rats by liquid chromatography-tandem mass spectrometry

The glycosides of flavonoid, anthocyanins and A type proanthocyanidins in cranberry concentrate were characterized and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cranberry concentrate (1 g/body weight) was orally gavaged to Fischer-344 rats (n = 6), and blood and urine samples were collected over 24 h periods. Quercetin, 3'-O-methylquercetin (isorhamnetin), myricetin, kaempferol, and proanthocyanidin dimer A2, together with thirteen conjugated metabolites of quercetin and methylquercetin and intact peonidin 3-O-galactoside and cyanidin 3-O-galactoside were identified in the rat urine after cranberry treatment. Very low levels of isorhamnetin (0.48 ± 0.09 ng/mL) and proanthocyanidin dimer A2 (0.541 ± 0.10 ng/mL) were found in plasma samples after 1 h of cranberry administration. Although no quercetin was detected in plasma, MRM analysis of the methanolic extract of urinary bladder showed that chronic administration of cranberry concentrate to rats resulted in accumulation of quercetin and isorhamnetin in the bladder. These results demonstrate that cranberry components undergo rapid metabolism and elimination into the urine of rats and are present in the urinary bladder tissue potentially allowing them to inhibit urinary bladder carcinogenesis.