Internal and external infections of fruits and seeds of peppers by Xanthomonas campestris pv. vesicatoria

1986 ◽  
Vol 64 (12) ◽  
pp. 2865-2871 ◽  
Author(s):  
Y. Bashan ◽  
Y. Okon
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Xanthomonas Campestris ◽  
Enrichment Culture ◽  
Disease Development ◽  
Bacterial Cells ◽  
Fibrillar Material ◽  
Bacterial Penetration ◽  
Fruit Surface ◽  
Scanning Electron

Fruit infection by Xanthomonas campestris pv. vesicatoria (Doidge 1920) Dye 1978 was monitored by scanning electron microscopy and by bacterial counts. Possible sites for bacterial penetration were through dead flowers and by proliferation of bacteria in the wart (small protuberance) area. Bacterial multiplication was observed in all warts of young, mature, and ripened fruits. Bacterial cells were bound to the fruit surface by fibrillar material. On the fruit surface, bacteria multiplied in small aggregates, submerged in slime. The slime consisted mainly of sucrose units. At later stages of disease development, the slime covered the entire fruit surface in young fruits. Typical scab symptoms appeared only in leaves of inoculated plants, whereas buds, flowers, and fruits of various sizes were symptomless, but later shed; shedding was strongest in young buds. In more mature and ripened fruits, bacterial numbers decreased and there was less shedding. Xanthomonas campestris pv. vesicatoria could be detected, in enrichment culture, in low numbers at the seed site (ovary) in inoculated fruits that did not shed.

Scanning electron microscopy of native biofilms on mung bean sprouts

2003 ◽  
Vol 49 (1) ◽  
pp. 45-50 ◽  
Author(s):  
William F Fett ◽  
Peter H Cooke
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Food Safety ◽  
Vigna Radiata ◽  
Mung Bean ◽  
Fibrillar Material ◽  
Mung Bean Sprouts ◽  
Native Microflora ◽  
Bean Sprouts ◽  
Scanning Electron

Native biofilms present on the adaxial surface of cotyledons of mung bean sprouts (Vigna radiata) were studied by use of scanning electron microscopy. Biofilms were abundant on the cotyledon surfaces and were comprised of rod-shaped bacteria, cocci-shaped bacteria, or yeasts, often with one type of microbe predominant. In contrast to our earlier study of biofilms on green sprouts (alfalfa, clover, broccoli, and sunflower), yeast and cocci were abundant on mung bean. Filamentous fungi were not observed. Sheet-like or fibrillar material (presumably composed of secreted microbial polysaccharides, proteins, lipids, and nucleic acids) fully or partially covered the biofilms. Biofilms up to 5 mm in length were observed, and some biofilms were comprised of more than just a monolayer of microbial cells. Native biofilms on sprout surfaces undoubtedly play an important role in the ecology of plant epiphytic microbes and may also afford protected sites for plant and human bacterial pathogens.Key words: mung bean sprouts, biofilms, native microflora, scanning electron microscopy, food safety.

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.

The development of the notochord in the chick embryo, studied by scanning and transmission electron microscopy

Development ◽  
1976 ◽  
Vol 35 (2) ◽  
pp. 383-401
Author(s):  
Mary Bancroft ◽  
Ruth Bellairs
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chick Embryo ◽  
Intercellular Spaces ◽  
Notochordal Cells ◽  
Fibrillar Material ◽  
Transmission Electron ◽  
Phases Of Development ◽  
Scanning Electron

The notochord of the chick embryo between stages 5 and 23 inclusive has been studied by scanning electron microscopy, supplemented by transmission electron microscopy. Three main phases of development are described, and these have been designated: bilaminar; rodlike, unvacuolated; rod-like and vacuolated. The change in shape of the organ from bilaminar to rod-like is accompanied by changes in the shape, orientation and position of the cells, an increase in the complexity of the cell contacts, and the laying down of a basal lamina. The change from the unvacuolated to the vacuolated phase is accompanied by increasing complexity within the cytoplasm. Most of the vacuoles are intracellular and appear empty though some contain a granular material. The notochordal sheath appears to be secreted by the notochordal cells and fine fibrillar material has been seen in the intercellular spaces. By stage 23, most of the notochordal cells have become so highly vacuolated that the cytoplasm has become closely packed around the nucleus.

scholarly journals Micromorphological Characteristics of Fruit Surfaces of Some Usable Species of the Genus Valeriana (Valerianaceae) Among Ukrainian Flora

2021 ◽  
Vol 74 ◽  
Author(s):  
Olga Tsarenko ◽  
Galina Shikhaleyeva ◽  
Valentyna Minarchenko ◽  
Iryna Tymchenko ◽  
Olena Bulakh
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Shape ◽  
Valeriana Officinalis ◽  
Adaxial Side ◽  
Stomatal Complex ◽  
Aerial Parts ◽  
Periclinal Walls ◽  
Fruit Surface ◽  
Scanning Electron

Abstract The micromorphological features of the fruit surfaces of nine species of Ukrainian flora, namely Valeriana tuberosa L., Valeriana tripteris L., Valeriana rossica P. Smirn., Valeriana stolonifera Czern., Valeriana grossheimii Worosch, Valeriana sambucifolia Mikan fil., Valeriana officinalis L. s. str., Valeriana wolgensis Kazak. [ Valeriana officinalis var. nitida (Kreyer) Rostanski], and Valeriana simplicifolia (Rchb.) Kabath, were examined. Depending on the presence and localization of pubescence on the surface of the fruit, three groups of species were distinguished: those with glabrous fruits, those with fruits pubescent only on the adaxial side, and those with fruits pubescent on both sides. Scanning electron microscopy revealed the additional characteristics of the fruits (microsculpture of the fruit surface, shape of cuticular formations on the surface of the outer periclinal walls of epidermal cells and on the surface of hairs, and structure of the stomatal complex), which were useful for the identification of the species. At the supraspecific level, the revealed features of the fruit surfaces somewhat overlapped and could be used to identify series and sections only as additional features. Based on the studied samples from herbarium material (KW), V. officinalis var. nitida was considered synonymous with V. wolgensis since there were no micromorphological differences between their fruits. The detailed micromorphological characteristics of the fruit surfaces of all the studied species can be used for further comparative morphological investigations of different aerial parts to identify stable features independent of geographic and ecological conditions.

Scanning electron microscopy of mouse ciliated oviduct and tracheal epithelium infected in vitro with Bordetella pertussis

1983 ◽  
Vol 29 (4) ◽  
pp. 415-420 ◽  
Author(s):  
Lauren B. Opremcak ◽  
Melvin S. Rheins
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Organ Culture ◽  
Bordetella Pertussis ◽  
Tracheal Ring ◽  
Fixation Method ◽  
Bacterial Cells ◽  
Ciliated Cells ◽  
Scanning Electron

Infection of mouse tracheal organ culture with Bordetella pertussis resulted in ciliostasis within 36 h. Scanning electron microscopy revealed that B. pertussis attached exclusively to ciliated cells but did not induce expulsion of this cell type at a test interval of 48 h. Mouse oviduct organ culture infected with B. pertussis demonstrated the same strict tropism for ciliated cells as in the tracheal ring system. Only ciliated cells were parasitized, becoming heavily colonized 48 h postinfection. Infected ciliated oviduct cells were not extruded. A fixation method which enhances fine structure was used in the scanning electron microscope studies. Bacterial fimbriae were not observed as the method of attachment of B. pertussis to cilia but fine fibers were seen extending between cilia and bacterial cells.

scholarly journals Preload loss and bacterial penetration on different implant-abutment connection systems

2010 ◽  
Vol 21 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Antônio Pedro Ricomini Filho ◽  
Frederico Silva de Freitas Fernandes ◽  
Fabiana Gouveia Straioto ◽  
Wander José da Silva ◽  
Altair Antoninha Del Bel Cury
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Cycling ◽  
Yeast Extract ◽  
Bacterial Colonization ◽  
Significance Level ◽  
Mechanical Fatigue ◽  
Implant Abutment ◽  
Bacterial Penetration ◽  
Scanning Electron

Preload loss can favor the occurrence of implant-abutment interface misfit, and bacterial colonization at this interface may lead to implant failure. The aim of this study was to evaluate the preload loss and bacterial penetration through the implant-abutment interface of conical and external hexagon connection systems subjected to thermal cycling and mechanical fatigue (TM). Four different implant-abutment connection systems were evaluated (n=6): external hexagon with universal post, Morse taper with universal post, Morse taper with universal post through bolt, and locking taper with standard abutment. The assemblies (implant-abutment) were subjected to a thermal cycling regimen (1,000 cycles of 5°C and 55°C) and to mechanical fatigue (1.0 million cycles, 1.0 Hz, 120 N). The assemblies were immersed in Tryptic Soy + Yeast Extract broth containing Streptococcus sanguinis and incubated at 37°C and 10% CO2 for 72 h. Detorque values were recorded. The bacterial penetration was assessed and the abutments were observed by scanning electron microscopy. The preload data were analyzed statistically by two-way ANOVA and Tukey’s test at 5% significance level. All screw abutment systems showed significantly higher (p<0.05) detorque values when subjected to TM and all conical systems presented bacterial penetration. The results show no relationship between the preload loss and the bacterial penetration.

scholarly journals Low-density polyethylene films incorporated with silver nanoparticles to promote antimicrobial efficiency in food packaging

2019 ◽  
Vol 26 (4) ◽  
pp. 353-366
Author(s):  
Sabrina da Costa Brito ◽  
Joana D Bresolin ◽  
Kátia Sivieri ◽  
Marcos D Ferreira
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Food Packaging ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Bacterial Cells ◽  
Scanning Calorimetry ◽  
Polyethylene Films ◽  
Scanning Electron

Technological innovations in packaging are intended to prevent microbiological contaminations for ensuring food safety and preservation. In this context, researchers have investigated the antimicrobial effect of low-density polyethylene films incorporated with the following concentrations of silver nanoparticles: 1.50, 3.75, 7.50, 15.00, 30.00, 60.00, and 75.00 µg/ml. The films were characterized using field emission gun scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry. From the results of these techniques, it could be concluded that the silver nanoparticles incorporated in the low-density polyethylene films did not influence their physical, chemical, and thermal properties. The direct contact assays, shake-flask assays, and bacterial images obtained using scanning electron microscopy were used to analyze the antimicrobial activity of the films. In the microbial analyses, it was verified that the nanostructured films exhibited antimicrobial properties against all the microorganisms studied, although more notably for fungi and Gram-negative bacteria than the Gram-positive bacteria. Moreover, it was discovered that the packages, in which silver nanoparticles were incorporated, inhibited the growth and reproduction of bacterial cells during the early stages. These results suggest that the extruded low-density polyethylene films incorporated with silver nanoparticles may be an essential tool for improving food quality and safety.

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