Specificity of bacterial attachment sites on the filamentous diatom Navicula confervacea (Bacillariophyceae)

1992 ◽  
Vol 38 (7) ◽  
pp. 676-686 ◽  
Author(s):  
James R. Rosowski
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Adhesion ◽  
Bacterial Flora ◽  
Bacterial Attachment ◽  
Aqueous Environment ◽  
Bacterial Development ◽  
Attachment Sites ◽  
Attachment Structures ◽  
Scanning Electron

The association in soil–water cultures of bacteria with the siliceous wall (frustule) of Navicula confervacea was examined with scanning electron microscopy. This diatom is filamentous through serial valve–face unions. Thus, the valve mantle and girdle bands are exposed to the aqueous environment and its bacterial flora, whereas the internally isolated adhering valve–face surfaces are not. Secretion of diatom mucilage strands occurred largely from parallel slits in the valve mantle and from valve–band and band–band sutures. These strands appeared to create a surface environment that discouraged bacterial adhesion. However, as the diatoms divided, their newly exposed mucilage-free bands provided a substratum for bacterial attachment. Dense aggregates of bacteria sometimes occurred at frustule apices, where filaments most easily bend and where recently formed adjacent hypovalves emerge. Along mucilage-free segments of the diatom filament, bacterial development occasionally engulfed the frustules; more commonly, bacteria were sparse but in specific locations. Bacterial attachment structures were mostly straight fibers, even on cocci, whereas strands from diatoms were contorted. Attachment by rods and spirilla was most often by their apices, with or without obvious lateral anchoring fibers. Scanning electron microscopy of cocci, rods, vibrio, and spirilla suggests that these bacteria initially prefer mucilage-free attachment sites near openings likely to leak cellular nutrients, i.e., slits of the mantle and band sutures rather than on the substratum between them, where presumably, other nutrients would have been available through their adsorption from the medium. Key words: bacterial adhesion, diatom girdle, mucilage, trail fibers.

Influence of Titanium Alloying Element Substrata on Bacterial Adhesion

2012 ◽  
Vol 535-537 ◽  
pp. 992-995
Author(s):  
Kun Mediaswanti ◽  
Vi Khanh Truong ◽  
Jafar Hasan ◽  
Elena P. Ivanova ◽  
Francois Malherbe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Bacterial Adhesion ◽  
Infection Risk ◽  
Bacterial Attachment ◽  
Bacterial Strains ◽  
Alloying Element ◽  
Bacteria Adhesion ◽  
Scanning Electron

Titanium and titanium alloys have been widely employed in many load-bearing orthopaedic applications due to their excellent strength and corrosion resistance. However, postimplantation infections might occur even though considerable studies have been made. Choosing a bio-friendly alloying element is one way to reduce infection risk. The aim of this study is to evaluate the extent of bacterial attachment on titanium, tantalum, niobium and tin surfaces. Two pathogenic bacterial strains, namely Staphylococcus aureus CIP 65.8T and Pseudomonas aeruginosa ATCC 9027, were used in this study. Quantification of bacterial attachment was performed using scanning electron microscopy. Results indicated that the surface chemistry and topography of the investigated materials significantly influence the degree of P. aeruginosa and S. aureus adhesion; however, surface wettability did not show a significant impact upon bacterial retention. In this study, tin was shown to be the most attractive material for bacteria adhesion but tantalum limits the bacterial adhesion. Therefore, it is suggested to limit the amount of tin as an titanium alloying element due to its nature to attract P. aeruginosa and S. aureus adhesion.

Sausage Casings as a Model for Attachment of Salmonella to Meat

1993 ◽  
Vol 56 (5) ◽  
pp. 390-394 ◽  
Author(s):  
ISABEL WALLS ◽  
PETER H. COOKE ◽  
ROBERT C. BENEDICT ◽  
ROBERT L. BUCHANAN
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Attachment ◽  
Bacterial Cells ◽  
Inoculum Level ◽  
Plate Counts ◽  
Increasing Temperature ◽  
Convenient Model ◽  
Sausage Casing ◽  
Scanning Electron

Artificial sausage casings were used as a model for studying bacterial attachment to meat connective tissue. Sausage casings of known mass were exposed to suspensions of Salmonella typhimurium in 0.15 M NaCl under various time, temperature, and inoculum level regimes, then washed to remove unattached bacteria. Attached bacterial cells were enumerated using both plate counts and scanning electron microscopy. Bacterial cells attached to sausage casing surfaces within 1 min of incubation. Numbers of attached cells increased with increasing temperature and inoculum levels and with time. Rates of attachment of S. typhimurium to sausage casings were comparable with those reported for attachment to meat surfaces. Sausage casings appear to be a convenient model for examining mechanisms of bacterial attachment to meats.

scholarly journals In VitroAdherence of Oral Bacteria to Different Types of Tongue Piercings

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lucas Pereira Borges ◽  
Julio Cesar Campos Ferreira-Filho ◽  
Julia Medeiros Martins ◽  
Caroline Vieira Alves ◽  
Bianca Marques Santiago ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Adhesion ◽  
Oral Bacteria ◽  
The Other ◽  
Control Group ◽  
Colony Forming Units ◽  
Different Types ◽  
Scanning Electron

The purpose of this work was to verifyin vitroadherence ofE. corrodensandS. oralisto the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5 mL of BHI broth and 50 μL of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis (pvalue<0.05). ForE. corrodens, difference among types of material was observed (p<0.001) and titanium and surgical steel showed lower bacterial adherence. The adherence ofS. oralisdiffered among piercings, showing lower colonization (p<0.007) in titanium and surgical steel piercings. The four types of piercings were susceptible to colonization byE. corrodensandS. oralis, and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

scholarly journals Bacterial Adhesion and Surface Roughness for Different Clinical Techniques for Acrylic Polymethyl Methacrylate

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lucas Costa de Medeiros Dantas ◽  
João Paulo da Silva-Neto ◽  
Talita Souza Dantas ◽  
Lucas Zago Naves ◽  
Flávio Domingues das Neves ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Roughness ◽  
Bacterial Adhesion ◽  
Surface Finishing ◽  
Fabrication Method ◽  
The Mean ◽  
One Way Anova ◽  
Roughness Measurements ◽  
Scanning Electron

This study sought to assess the effect of different surface finishing and polishing protocols on the surface roughness and bacterial adhesion (S. sanguinis) to polymethyl methacrylates (PMMA). Fifty specimens were divided into 5 groups (n=10) according to their fabrication method and surface finishing protocol: LP (3 : 1 ratio and laboratory polishing), NF (Nealon technique and finishing), NP (Nealon technique and manual polishing), MF (3 : 1 ratio and manual finishing), and MP (3 : 1 ratio and manual polishing). For each group, five specimens were submitted to bacterial adhesion tests and analyzed by scanning electron microscopy (SEM). Two additional specimens were subjected to surface topography analysis by SEM and the remaining three specimens were subjected to surface roughness measurements. Data were compared by one-way ANOVA. The mean bacterial counts were as follows: NF,19.6±3.05; MP,5.36±2.08; NP,4.96±1.93; MF,7.36±2.45; and LP,1.56±0.62(CFU). The mean surface roughness values were as follows: NF,3.23±0.15; MP,0.52±0.05; NP,0.60±0.08; MF,2.69±0.12; and LP,0.07±0.02(μm). A reduction in the surface roughness was observed to be directly related to a decrease in bacterial adhesion. It was verified that the laboratory processing of PMMA might decrease the surface roughness and consequently the adhesion ofS. sanguinisto this material.

Observation of corynebacterium species using Scanning Electron Microscopy

1993 ◽  
Vol 51 ◽  
pp. 794-795
Author(s):  
Toya S. McWilliams ◽  
Ernest C. Hammond ◽  
Marlene B. Luzarraga
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Flora ◽  
Exponential Growth Phase ◽  
Laboratory Mice ◽  
Healthy Individuals ◽  
Corynebacterium Species ◽  
Genus Corynebacterium ◽  
Pleomorphic Cells ◽  
Scanning Electron

Bacteria of the genus Corynebacterium are considered part of the bacterial flora of skin and mucosa. Even C. diphtheriae, a long recognized pathogen, may be isolated from the throat of healthy individuals. Recent evidence indicates that other Corynebacteria are associated with opportunistic conjunctival infections in aging laboratory mice.Our goal of using scanning electron microscopy was to expand previous studies and to observe the association of the bacteria with the conjunctival surface of aged mice. To accomplish this, we needed a point of reference for identification of the corynebacteria which were frequently present in the company of other bacteria. We studied cultures of known corynebacteria of ocular origin during the exponential growth phase. These cultures contained pleomorphic cells that were round, ovoid and rod shaped, clustered together and surrounded by a biofilm. Several of the cylindrical rods appeared as V-shaped pairs, classic features of the genus Corynebacterium. The V-shape arrangement is accomplished by a snapping postfission movement.

scholarly journals Getting a Grip on the Adhesion Mechanism of Epiphytic Orchids – Evidence From Histology and Cryo-Scanning Electron Microscopy

2021 ◽  
Vol 4 ◽  
Author(s):  
Jessica Y. L. Tay ◽  
Gerhard Zotz ◽  
Stanislav N. Gorb ◽  
Helena J. R. Einzmann
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Root Hairs ◽  
Root Bark ◽  
Epiphytic Orchids ◽  
Epiphytic Orchid ◽  
Vascular Epiphytes ◽  
Attachment Structures ◽  
Cryo Scanning Electron Microscopy ◽  
Scanning Electron

Plants and animals evolve different attachment structures and strategies for reversible or permanent adhesion to different substrate types. For vascular epiphytes, having the ability to permanently attach to their host plants is essential for establishment and survival. Unlike mistletoe roots, roots of vascular epiphytes do not penetrate the host tissues but instead achieve attachment by growing in close contact to the surface of the substrate. However, the fundamental understanding of the attachment functions of epiphytic roots remains scarce, where majority of studies focused on the general root morphology, their functional properties and the descriptions of associated microbial endophytes. To date, research on attachment strategies in plants is almost entirely limited to climbers. Therefore, this study aims to fill the knowledge gap and elucidate the attachment functions of roots of epiphytic orchids. With the use of histology and high-resolution cryo-scanning electron microscopy (cryo-SEM) technique with freeze fracturing, the intimate root-bark substrate interface of epiphytic orchid Epidendrum nocturnum Jacq was investigated. Results showed a flattened underside of the root upon contact with the substrate surface, and the velamen layer appeared to behave like a soft foam, closely following the contours of the substrate. Root hairs emerged from the outermost velamen layer and entered into the crevices in the substrate, whenever possible. A layer of amorphous substance (glue-like substance) was observed on the surface of the root hairs. Combining the observations from this study and knowledge from previous studies, we hypothesised that epiphytic orchid roots produced a layer of glue-like substance to adhere the root to the substrate. Then root hairs are produced and enter into the voids and crevices of the substrate. This further generates a mechanical interlocking mechanism between root and substrate, thus reinforcing the attachment of the root (and hence the whole plant) to its substrate.

Secondary Electron Imaging of Liquid Water Films in the Environmental Scanning Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 374-375
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Liquid Water ◽  
Secondary Electron ◽  
Gas Pressure ◽  
Aqueous Environment ◽  
Water Films ◽  
Electron Imaging ◽  
Scanning Electron ◽  
Gas Pressures

High gas pressure scanning electron microscopy is now routinely possible with new microscopes operating between 0.1 and 20 torr gas pressure. Since the specimen chamber is separated from the electron optical column by pressure-limiting apertures, high gas pressures present at the level of the specimen do not affect the high vacuum in the column. The use of a single PLA underneath the last probe-forming lens allows maintainance of ∼0.1 torr. Twenty torr can be stabilized with two PLA, forming two differentially pumped pressure zones which may be incorporated into the last probe-forming lens.One of the most important new features of high gas pressure microscopy is the possibility to alter the type of gas and its pressure over a large range. High gas pressures (>1 torr) are required for charge neutralization on rugged insulators and for gas amplification of the SE signal. Additionally, using water vapors, liquid water can be stabilized. However, the aqueous environment is only one example among many possibilities.The secondary electron imaging of liquid water is a fascinating new aspect of scanning electron microscopy. At saturated water vapor pressures, water is stable indefinitely. Increasing or decreasing the vapor pressure allows condensation or evaporation of water and provides means to generate water films. As can be seer from Fig. 1, the stabilizing pressure for water at 20°C is 17.5 torr. Such a pressure would require a very short working distance for SE imaing. Therefore, it is preferable to reduce the specimen temperature and to establish vapor saturation at lower pressures. However, liquid water can only be stabilized at pressures greater than ∼4.5 torr.

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