Adhesion of bacteria to epithelial cell surfaces within the reticulo-rumen of cattle.

Blocks of tissue were removed from various locations in the bovine digestive tract and fixed and processed for transmission and scanning electron microscopy by techniques that retained adherent bacteria. The distribution of bacteria on the surface of epithelial cells was examined by scanning electron microscopy. This showed intermittent colonization of the epithelia with the formation of occasional microcolonies of morphologically similar bacterial cells. Transmission electron microscopy of ruthenium red-stained material showed the presence of both the glycocalyx of the bovine epithelial cells and fibrous carbohydrate coats surrounding adherent bacteria. The carbohydrate coats appeared to mediate the attachment of bacteria to the epithelium, to food particles, and to each other so that microcolonies were formed. Careful examination of the bacterial colonization of keratinized cells in the process of being sloughed from the surface of the stratified squamous epithelium of the rumen showed that these dead cells were digested by adherent bacteria of a limited number of morphological types. The spatial relationship of this mixed, adherent, microbial population to living and dead epithelial cells and to food particles indicates that digestive processes of some importance may be accomplished by this stationary component of the microbial flora of the digestive tract.     

Adhesion of bacteria from mixed cell suspension to solid surfaces

The attachment of four species of bacteria to solid surfaces was investigated to determine whether the attachment of one species of bacterium could be influenced by the presence of other attaching or attached species. Three types of experiment were done: (i) attachment of bacteria from suspensions containing two species (termed simultaneous attachment) was compared to attachment of each species in pure culture, (ii) the attachment of one species of bacterium to surfaces already colonized by a second species (termed sequential attachment) was compared to attachment of the bacteria to clean, uncolonized surfaces, and (iii) bacteria were allowed to attach to a surface already colonized by a second strain, and their effect on the stabilization of adhesion of the initial colonizing strain was determined. The bacteria were Acinetobacter calcoaceticus, a Staphylococcus sp., a coryneform (isolates from a canning factory), and Staphylococcus aureus. The surfaces were tin plate, glass, and nylon. The attachment of each species was either increased, decreased or not affected by the simultaneous or sequential attachment of another species. The results depended upon the species combination, the surface composition, and the sequence of attachment. The detachment of a primary colonizing species was either increased, decreased or not affected by the subsequent attachment of a second species, depending on the species combination and surface. The results demonstrate that bacterial attachment to a surface can be influenced by the composition of the attaching population and can differ considerably from the attachment of the component species in pure culture. This has implications for the control and removal of biofilms in food processing plants, as well as a wider significance for the composition and dynamics of biofilms in industrial and natural environments.Abbreviation PYE Peptone/yeast extract medium     

Adhesion of biodegradative anaerobic bacteria to solid surfaces.

In order to exploit the ability of anaerobic bacteria to degrade certain contaminants for bioremediation of polluted subsurface environments, we need to understand the mechanisms by which such bacteria partition between aqueous and solid phases, as well as the environmental conditions that influence partitioning. We studied four strictly anaerobic bacteria, Desulfomonile tiedjei, Syntrophomonas wolfei, Syntrophobacter wolinii, and Desulfovibrio sp. strain G11, which theoretically together can constitute a tetrachloroethylene- and trichloroethylene-dechlorinating consortium. Adhesion of these organisms was evaluated by microscopic determination of the numbers of cells that attached to glass coverslips exposed to cell suspensions under anaerobic conditions. We studied the effects of the growth phase of the organisms on adhesion, as well as the influence of electrostatic and hydrophobic properties of the substratum. Results indicate that S. wolfei adheres in considerably higher numbers to glass surfaces than the other three organisms. Starvation greatly decreases adhesion of S. wolfei and Desulfovibrio sp. strain G11 but seems to have less of an effect on the adhesion of the other bacteria. The presence of Fe(3+) on the substratum, which would be electropositive, significantly increased the adhesion of S. wolfei, whereas the presence of silicon hydrophobic groups decreased the numbers of attached cells of all species. Measurements of transport of cells through hydrophobic-interaction and electrostatic-interaction columns indicated that all four species had negatively charged cell surfaces and that D. tiedjei and Desulfovibrio sp. strain G11 possessed some hydrophobic cell surface properties. These findings are an early step toward understanding the dynamic attachment of anaerobic bacteria in anoxic environments.     

Adhesion of algal cells to surfaces

This paper reports the cell–substratum interactions of planktonic (Chlorella vulgaris) and benthic (Botryococcus sudeticus) freshwater green algae with hydrophilic (glass) and hydrophobic (indium tin oxide) substrata to determine the critical parameters controlling the adhesion of algal cells to surfaces. The surface properties of the algae and substrata were quantified by measuring contact angle, electrophoretic mobility, and streaming potential. Using these data, the cell–substratum interactions were modeled using thermodynamic, DLVO, and XDLVO approaches. Finally, the rate of attachment and the strength of adhesion of the algal cells were quantified using a parallel-plate flow chamber. The results indicated that (1) acid–base interactions played a critical role in the adhesion of algae, (2) the hydrophobic alga attached at a higher density and with a higher strength of adhesion on both substrata, and (3) the XDLVO model was the most accurate in predicting the density of cells and their strength of adhesion. These results can be used to select substrata to promote/inhibit the adhesion of algal cells to surfaces.     

Adhesion of cells to polystyrene surfaces

The surface treatment of polystyrene, which is required to make polystyrene suitable for cell adhesion and spreading, was investigated. Examination of surfaces treated with sulfuric acid or various oxidizing agents using (a) x-ray photoelectron and attenuated total reflection spectroscopy and (b) measurement of surface carboxyl-, hydroxyl-, and sulfur-containing groups by various radiochemical methods showed that sulfuric acid produces an insignificant number of sulfonic acid groups on polystyrene. This technique together with various oxidation techniques that render surfaces suitable for cell culture generated high surface densities of hydroxyl groups. The importance of surface hydroxyl groups for the adhesion of baby hamster kidney cells or leukocytes was demonstrated by the inhibition of adhesion when these groups were blocked: blocking of carboxyl groups did not inhibit adhesion and may raise the adhesion of a surface. These results applied to cell adhesion in the presence and absence of serum. The relative unimportance of fibronectin for the adhesion and spreading of baby hamster kidney cells to hydroxyl-rich surfaces was concluded when cells spread on such surfaces after protein synthesis was inhibited with cycloheximide, fibronectin was removed by trypsinization, and trypsin activity was stopped with leupeptin.     

Understanding the binding of bacteria to plant surfaces

Many of the bacteria that associate with plants bind tenaciously to plant cells. This characteristic appears to have important functional implications for the inception of disease-causing and symbiotic interactions. Although binding is complex and as yet poorly understood, experimental manipulation of this process holds promise for improved plant productivity.     

Adhesion of cellulolytic ruminal bacteria to barley straw

Adhesion of the cellulolytic ruminal bacteria Ruminococcus flavefaciens and Fibrobacter succinogenes to barley straw was measured by incubating bacterial suspensions with hammer-milled straw for 30 min, filtering the mixtures through sintered glass filters, and measuring the optical densities of the filtrates. Maximum adhesion of both species occurred at pH 6.0 and during mid- to late-exponential phase. Adhesion was saturable at 33 and 23 mg (dry weight) g of straw for R. flavefaciens and F. succinogenes, respectively. Methyl cellulose and carboxymethyl cellulose inhibited adhesion by 24 to 33%. Competition between species was determined by measuring characteristic cell-associated enzyme activities in filtrates of mixtures incubated with straw; p-nitrophenyl-beta-d-lactopyranoside hydrolysis was used as a marker for F. succinogenes, while either beta-xylosidase or carboxymethyl cellulase was used for R. flavefaciens, depending on the other species present. R. flavefaciens had no influence on F. succinogenes adhesion, and F. succinogenes had only a minor (<20%) effect on R. flavefaciens adhesion. The noncellulolytic ruminal bacteria Bacteroides ruminicola and Selenomonas ruminantium had no influence on adhesion of either cellulolytic species, although these organisms also adhered to the straw. We concluded that R. flavefaciens and F. succinogenes have separate, specific adhesion sites on barley straw that are not obscured by competition with non-cellulolytic species.     

Adhesion of water stressed Helicobacter pylori to abiotic surfaces

AIM: The main aim of this work was to study and compare the adhesion of water exposed Helicobacter pylori to six different substrata and correlate any changes in morphology, physiology, ability to form aggregates and cultivability when in the planktonic or in the sessile phase. METHODS AND RESULTS: The number of total cells adhered for different water exposure times and modifications in the cell shape were evaluated using epifluorescence and scanning electron microscopy, and physiology assessed using Syto9 and propidium iodide (PI) cellular uptake. All abiotic surfaces were rapidly colonized by H. pylori, and colonization appeared to reach a steady state after 96 h with levels ranging from 2.3 x 10(6) to 3.6 x 10(6) total cells cm(-2). Cell morphology was largely dependent on the support material, with spiral bacteria, associated with the infectious form of H. pylori, subsisting in a higher percentage on nonpolymeric substrata. Also, sessile bacteria were generally able to retain the spiral shape for longer when compared with planktonic bacteria, which became coccoid more quickly. The formation of large aggregates, which may act as a protection mechanism against the negative impact of the stressful external environmental conditions, was mostly observed on the surface of copper coupons. However, Syto9 and PI staining indicates that most of H. pylori attached to copper or SS304 have a compromised cell membrane after only 48 h. Cultivability methods were only able to detect the bacteria up to the 2 h exposure-time and at very low levels (up to 500 CFU cm(-2)). CONCLUSIONS: The fact that the pathogen is able to adhere, retain the spiral morphology for longer and form large aggregates when attached to different plumbing materials appeared to point to pipe materials in general, and copper plumbing in particular, as a possible reservoir of virulent H. pylori in water distribution systems. However, the Syto9/PI staining results and cultivability methods indicate that the attached H. pylori cells quickly enter in a nonviable physiological state. SIGNIFICANCE AND IMPACT OF THE STUDY: This represents the first study of H. pylori behaviour in water-exposed abiotic surfaces. It suggests that co-aggregation with the autochthonous heterotrophic consortia present in water is necessary for a longer survival of the pathogen in biofilms associated to drinking water systems.     

Binding of epithelial cells to lectin-coated surfaces

Summary Epithelial cells may relate to their basement membrane substrates via lectin-like interactions. In a model system for study of this type of interaction, lectin-coated bacteriological plastic petri dishes were presented as substrates for epithelial cell adhesion. Of 21 lectins tested by mixed agglutination against two epithelial cell types, Madin-Darby canine kidney (MDCK), and human embryonic kidney cells (HEK), nine gave less than 5% rosettes and 12 gave 5 to 50% rosettes. Wheat germ agglutinin (WGA) andGeodia cydonium lectin gave the highest percentage of rosettes. Wheat germ agglutinin was readily adsorbed to plastic surfaces and maintained specificity in binding interactions. Both MDCK and HEK cells attached as well to WGA coated petri dishes as to conventional tissue culture dishes. Furthermore, both spread over the lectin-coated surfaces. The MDCK cells grew to confluence and could be subcultured and maintained indefinitely on such surfaces, although WGA in solution was toxic to the cells in concentrations as low as 0.1 to 1.0 μg/ml. Cell attachment to WGA coated dishes was blocked by cycloheximide only if the cells had been preincubated with the inhibitor for several hours. Cell attachment was not inhibited by pretreatment of cells with neuraminidase. Precoating cells with WGA blocked binding to both WGA-coated surfaces and untreated tissue culture dishes. Cells attached to WGA-coated dishes could not be readily dislodged by trypsin-EDTA for the first 2 h after subculture. By 4 h, attachment was again trypsin sensitive, suggesting that the cells synthesized a trypsin-sensitive material that was laid down between the cell surface and the WGA-coated dish. Regeneration of trypsin sensitivity was not blocked by cycloheximide. This work was supported by Research Grant AG01986 from the National Institutes of Health, Bethesda, Maryland.     

Adhesion of group B streptococci to vaginal epithelial cells

The work presents the results of studies on the optimum and standard conditions for the in vitro determination of the adhesiveness of group B streptococci with epithelial cell suspensions. Vaginal epithelium has proved to be the most convenient and adequate system for studying the adhesiveness of group B streptococci. The optimum infective dose of these bacteria has been found to range from 50 to 200 cocci per cell. The characteristics of the adhesion of group B streptococci to vaginal epithelium are highly reproducible and exhibit low dependence on the time of the incubation of the bacteria with epithelial cells; fluctuations in the adhesiveness of the cultures in the definite range of pH shifts are seemingly determined by the serotype of the strains.     

Adhesion of Salmonella dublin to HEp2 epithelial cells

Two strains of Salmonella dublin , grown serially in brain heart infusion broth, were motile and produced mannose sensitive (MS) but not mannose resistant (MR) haemagglutinins; grown on phosphate buffered agar, the strains were poorly motile and phenotypically MSHA^- MRHA ⁺. In adhesion tests with HEp2 epithelial cells, broth grown bacteria that were motile and MSHA⁺ MRHA^- adhered better than agar grown bacteria that were poorly motile and MSHA^- MRHA⁺. Thus, in adhesion tests with HEp2 epithelial cells, strains of S. dublin behaved like S. typhimurium strains in that their HEp2 cell adhesiveness was associated with motility and production of MSHA.     

Adsorption of polarly flagellated bacteria to surfaces

Studies have been made of the initial stages in adsorption of several polarly flagellated marine bacteria to glass surfaces. Bacteria attach at the pole of flagellar insertion, and after a brief period (from a few seconds to a few minutes) of rotation around the attachment axis, become immobile. Soma do not spin or gyrate while the organisms rotate slowly. Flagellar activity continues for several minutes after soma immobilization. Tween 80 inhibits bacterial attachment, and deflagellated organisms do not adsorb to glass. Bacteria rendered nonmotile with sodium azide (NaN₃) rapidly adsorb to glass and cannot be removed by washing with artificial seawater or a solution of 2.4% NaCl. It is proposed that both flagella-surface and somasurface interactions are involved in bacterial attachment. Bacterial flagella may play an important ecological role as attachment organelles.     

The process of epithelial cell attachment to glass surfaces studied by reflexion contrast microscopy

The process of attachment was studied in primary mouse kidney epithelial cell cultures by means of reflexion contrast microscopy, a method developed for studying the cell membrane-substrate relationship. The first in a series of events is simple adherence to the substrate, called close contact. This phenomenon is associated with the greatest extension of lamellar cytoplasm and the fewest number of cell nuclei/unit area. The nuclei of such cells are in close contact with the bottom portion of the cell membrane. Approx. 24 h after planting, as the cultures become more crowded, cells develop a different kind of attachment to the substrate—focal contacts—that are correlated with a decrease in lamellar cytoplasm. Cells detached from the substrate after close contact formation readily reattach, while cells detached after formation of focal contacts do not reattach. After incubation for periods greater than 5 days, the dense cultures degenerate and cells lose their attachment to the glass surface.     

Adhesion of fungal spores and germlings to host plant surfaces

Summary Firm adhesion of fungal plant pathogens to their hosts is critical at several stages in the host-parasite interaction. Spores of many fungal species are capable of rapid, non-specific attachment to various surfaces. This early adhesion, which often occurs well before germ tube emergence, prevents spores from being blown or washed from the host surface before infection can take place. Adhesion is critical for proper sensing of topographic signals involved in thigmotropic responses and for differentiation and function of appressoria. Four fungal pathogens which exhibit a variety of adhesion mechanisms have been selected for discussion.Abbreviations EMC extracellular matrix - FSTEM freeze-substitution transmission electron microscopy - Con A concanavalin A - CryoSEM cryo scanning electron microscopy - MTM macroconidial tip mucilage - STM spore tip mucilage     

Adhesion of Lactobacillus isolates to intestinal epithelial cells of chicken

L.Z. JIN, Y.W. HO, M.A. ALI, N. ABDULLAH, K.B. ONG AND S. JALALUDIN. 1996. A total of 46 Lactobacillus isolates obtained from chicken intestine were assessed on their ability to adhere to the chicken ileal epithelial cell (IEC) in vitro . Twelve out of the 46 isolates showed moderate to good ability to adhere to the IEC. Temperature (between 4°C and 42°C) did not affect attachment. Incubation (contact) time of 30 min was found to be insufficient for the attachment of bacteria to the IEC, but contact time beyond 1 h did not increase this ability. The pH values (4–7) of the suspending buffer did not have any significant effect on the attachment of bacteria to the IEC, but at pH 8 it was reduced significantly (P < 0.05).     

Attachment of lactic acid bacteria to beef-muscle surfaces

The effect of immersion time and cell concentration in the attachment of several lactic acid bacteria with antibacterial activity to beef-muscle surface was studied. The number of firmly attached bacteria increased with immersion time in the case ofPediococcus acidilacti, Lactobacillus sake, Lactococcus cremoris (two strains) andPediococcus acidilacti. Pediococcus pentosaceus, Lactococcus lactis andLactobacillus curvatus reached maximum adhesion after 15–30 min. The highest strength of attachment (Sr values) were observed after 15–30 min of contact, time except forP. pentosaceus. For all strains, the number of bacteria adhering to meat increased with increasing cell concentration in the adhesion medium. The highest strength of attachment was observed at a cell concentration of 10⁵/mL mainly forL. sake, L. lactis andL. cremoris. Due to their attachment characteristics,L. sake, L. lactis andL. cremoris are proposed as potential biocontrol agents because they could grow on meat surface and limit the potential attachment of pathogenic microorganisms.