L'infestation du myoépithélium de l'oesophage par des microorganismes pigmentés et la structure des organes à bactéries du vestibule chez le Bryozoaire Chilostome Palmicellaria skenei (E. et S.)

1986 ◽  
Vol 64 (9) ◽  
pp. 1842-1851 ◽  
Author(s):  
Geneviève Lutaud
Keyword(s):  
Digestive Tract ◽  
Bacterial Population ◽  
Myoepithelial Cells ◽  
Cortical Layer ◽  
Northern Coast ◽  
Filamentous Bacteria ◽  
Ultrastructural Examination ◽  
Autotrophic Bacteria

Blue lateral spots, corresponding to rows of myoepithelial cells invaded by spherular pigmented microorganisms, were observed in the oesophagus of every polypide in 75% of living colonies of Palmicellaria skenei from deep rocky sites off the northern coast of Brittany. Ultrastructural examination of the microorganisms showed that they are intracellular procaryonts with no membranous organelle of thylakoid structure. Their natural pigmentation and a cortical layer of vesicles cause them to resemble autotrophic bacteria with chlorophyllic pigments. The association is not obligatory, but it is specific and is restricted to the first contractile region of the digestive tract. Ultrastructural examination of the paired organs attached to the diaphragm of the tentacular sheath showed that each organ is formed by the adhesion of one of the glandular diverticula of the diaphragm to a pouch, itself derived from the vestibular wall and containing filamentous bacteria, which is divided by the folds of its internal cuticle. The structural characters of the bacteria are described. The interdigitated microvilli of the epithelium of this pouch and the presence inside it of fibrillated plates, probably originating from the adjacent secretory organ, suggest that there may be exchanges between the bacterial population and the host. The association is obligatory and probably symbiotic.

The digestive tract of the echinopluteus of Echinocardium cordatum (Echinodermata, Echinoida): its ultrastructure and innervation

1994 ◽  
Vol 72 (12) ◽  
pp. 2090-2099 ◽  
Author(s):  
Leonid P. Nezlin ◽  
Vladimir V. Yushin
Keyword(s):  
Digestive Tract ◽  
Anal Sphincter ◽  
Myoepithelial Cells ◽  
Lower Lip ◽  
Echinocardium Cordatum ◽  
Anal Opening

The digestive tract of the echinopluteus of Echinocardium cordatum consists of a tubular oesophagus, spherical stomach, and large hemispherical intestine. The oesophagus is constructed from cells of one ultrastructural type and has subepithelial muscles oriented circumferentially and longitudinally. The cardiac and pyloric sphincters separating the stomach from the oesophagus and intestine, as well as the anal sphincter, consist of myoepithelial cells and subepithelial muscles. The cells of both the stomach and intestine are able to absorb nutrients and phagocytize food. Neuron-like cells were detected around the mouth, in the oesophageal epithelium, and around the anal opening. Axonal trunks pass at the base of the oesophageal epithelium and around the sphincters. The rest of the digestive tract is innervated by solitary axons. Catecholamine-containing neurons were found inside the lower lip ganglion, in the two suboral ganglia, and around the anal opening.

Application of oligonucleotide probes for the detection of Thiothrix spp. in activated sludge plants treating paper and board mill wastes

2002 ◽  
Vol 46 (1-2) ◽  
pp. 559-564 ◽  
Author(s):  
S.B. Kim ◽  
M. Goodfellow ◽  
J. Kelly ◽  
G.S. Saddler ◽  
A.C. Ward
Keyword(s):  
Activated Sludge ◽  
Bacterial Population ◽  
Oligonucleotide Probe ◽  
In Situ Hybridisation ◽  
Filamentous Bacteria ◽  
Phylogenetic Groups ◽  
Investigation Period ◽  
Mixed Populations ◽  
Conventional Microscopy

Filamentous bacteria belonging to the genus Thiothrix were detected in activated sludge samples using the fluorescent in situ hybridisation (FISH) technique. A 16S rRNA-targeted oligonucleotide probe was developed for the detection of members of the T. fructosivorans group, and the performance of probe TNI for the detection of Thiothrix nivea group was enhanced by using an unlabeled competitor. A set of 5 probes covering all phylogenetic groups of Thiothrix were used to examine samples taken from selected activated sludge plants treating paper and board mill wastes. Members of the T. eikelboomii group formed the predominant filamentous bacterial population in plants experiencing poor sludge settleability, whereas members of the T. nivea group were commonly found but not dominantly in the remaining plants. Members of the T. fructosivorans group were not detected at any significant level in any of the samples. The distribution of the main Thiothrix types remained unchanged throughout the investigation period. It was evident that mixed populations of Thiothrix spp. were present in all activated sludge samples investigated, the observed differences were in the relative abundance of the various groups. These findings were supported by the results obtained using conventional microscopy.

scholarly journals Utilization of endogenous and dietary urea in the large intestine of the mature horse

1996 ◽  
Vol 76 (3) ◽  
pp. 373-386 ◽  
Author(s):  
R. G. Martin ◽  
N. P. McMeniman ◽  
B. W. Norton ◽  
K. F. Dowsett
Keyword(s):  
Digestive Tract ◽  
Large Intestine ◽  
Plasma Proteins ◽  
Crude Protein ◽  
Bacterial Population ◽  
N Balance ◽  
Plasma Urea ◽  
Dietary Crude Protein ◽  
N Metabolism ◽  
Soyabean Meal

The dynamics of N metabolism in mature horses were investigated when they were fed on a low-N diet or the same diet supplemented with sufficient urea or soyabean meal to meet their theoretical N requirements. There were no differences in DM, organic matter or neutral-detergent-fibre digestibilities for the three diets. N digestibilities and digestible-N intakes were similar for the urea- and soyabean-supplemented diets and very low for the low-N diet. For all three diets plasma urea was degraded in the digestive tract to NH3which was utilized by the bacterial population as a N source. NH3was absorbed from the large intestine into the blood and converted to urea. NH3was also incorporated into plasma proteins. The horses fed on the low-N diet degraded a greater proportion of endogenous urea in the digestive tract than did horses fed on the urea- or soyabean-supplemented diets. However, the horses fed on the urea diet had the highest degradation rate of urea. The quantity of urea degraded in the digestive tract of horses fed on the urea-supplemented and the low-N diets could not compensate for a lack of dietary crude protein in these diets. The horses were in a negative N balance when fed on the low-N and urea-supplemented diets and a positive N balance when fed on the soyabean-supplemented diet. Dietary urea supplementation did not benefit the horses.

Filamentous bacterial population dominance in activated sludges subject to stresses

2002 ◽  
Vol 46 (1-2) ◽  
pp. 49-53 ◽  
Author(s):  
G. Gaval ◽  
P. Duchène ◽  
J.-J. Pernelle
Keyword(s):  
Wastewater Treatment ◽  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
Bacterial Population ◽  
Filamentous Growth ◽  
Volume Index ◽  
Filamentous Bacteria ◽  
Sludge Volume Index ◽  
The One

Evolution of a filamentous bacterial population was monitored on four wastewater treatment pilot plants subject to stresses which have consisted of oxygen deficiencies and/or loading shocks. Fluorescent in situ hybridization (FISH) was used to perform filaments identification and quantification. Results obtained on the different pilot plants have led us to conclude that independently of the nature of the stresses, a single filamentous bacteria species was involved in the increase of the sludge volume index associated to the filamentous growth. In addition, when serial stresses were used, substitutions in dominant filamentous populations occurred: if another filament began to proliferate it caused the regression of the one which dominant.

Relationship Between Extracellular Neutral Protease Production and Appearance of Bleb-Like Evaginations in Pseudomonas fragi

1985 ◽  
Vol 48 (12) ◽  
pp. 1067-1070 ◽  
Author(s):  
S. S. THOMPSON ◽  
Y. M. NAIDU ◽  
J. J. PESTKA
Keyword(s):  
Cell Wall ◽  
Protease Activity ◽  
Bacterial Population ◽  
Proteolytic Enzymes ◽  
Brain Heart Infusion ◽  
Brain Heart Infusion Broth ◽  
Protease Production ◽  
Ultrastructural Examination ◽  
Pseudomonas Fragi ◽  
Extracellular Protease Activity

Pseudomonas fragi is one of several pseudomonads known to produce proteolytic enzymes. During growth of P. fragi in brain heart infusion broth (BHI) at 10°C, the bacterial population increased from 107 to over 1010 CFU/ml after 130 h, with a concurrent increase in pH from 7.4 to 8.5. Maximal extracellular protease activity occurred after 60 to 72 h. Ultrastructural examination of cells grown in BHI showed the presence of bleb-like evaginations of the cell wall. Similar structures were not detected when P. fragi was grown in Koser citrate broth, a medium which was unsuitable for supporting protease production by P. fragi.

Scanning electron microscopy of the digestive tract of larval Simulium ornatum Meigen (Complex) (Diptera: Simuliidae) and its associated microbial flora

1995 ◽  
Vol 73 (9) ◽  
pp. 1640-1646 ◽  
Author(s):  
Mark R. Taylor ◽  
Stephen T. Moss ◽  
Mike Ladle
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digestive Tract ◽  
Freeze Fracture ◽  
Microbial Flora ◽  
Peritrophic Membrane ◽  
Filamentous Bacteria ◽  
Direct Observations ◽  
Dissection Technique ◽  
Scanning Electron

The structure and microbial flora of the digestive tract of larval Simulium ornatum were investigated using scanning electron microscopy. Direct observations of the microbial communities associated with the endoperitrophic surface of the peritrophic membrane and the endocuticular surface of the hindgut are presented. The endoperitrophic surface was frequently devoid of bacteria, although the fungus Harpella melusinae (Harpellales, Trichomycetes) was commonly attached. Rarely, spirochaetes and coccoid bacteria were attached to the endoperitrophic surface. In contrast, the endocuticular surface was regularly colonized by a diverse microflora composed of rod-shaped, coccoid, spiral, and filamentous bacteria and two species of Harpellales (Trichomycetes). A freeze-fracture technique is compared with a dissection technique for exposing the endoperitrophic and endocuticular surfaces of the digestive tract.

Further Studies on the Ultrastructure of Harderian Gland in Adult Rats

1974 ◽  
Vol 32 ◽  
pp. 288-289
Author(s):  
Alfredo Feria-Velasco ◽  
Guadalupe Tapia-Arizmendi
Keyword(s):  
Fine Structure ◽  
Domestic Fowl ◽  
Animal Species ◽  
Acinar Cells ◽  
Harderian Gland ◽  
Myoepithelial Cells ◽  
The Other ◽  
Albino Rats ◽  
Adult Rats ◽  
Cell Components

The fine structure of the Harderian gland has been described in some animal species (hamster, rabbit, mouse, domestic fowl and albino rats). There are only two reports in the literature dealing on the ultrastructure of rat Harderian gland in adult animals. In one of them the author describes the myoepithelial cells in methacrylate-embbeded tissue, and the other deals with the maturation of the acinar cells and the formation of the secretory droplets. The aim of the present work is to analize the relationships among the acinar cell components and to describe the two types of cells located at the perifery of the acini.

The application of electron microscopy to diagnosis in gynecologic neoplasms and tumor-like conditions

1984 ◽  
Vol 42 ◽  
pp. 102-105
Author(s):  
Lawrence M. Roth
Keyword(s):  
Electron Microscopy ◽  
Reproductive Tract ◽  
Malignant Tumors ◽  
Frozen Section ◽  
Cost Effective ◽  
Female Reproductive Tract ◽  
Ultrastructural Examination ◽  
Specific Diagnosis ◽  
Potential Value ◽  
Gynecologic Neoplasms

The female reproductive tract may be the site of a wide variety of benign and malignant tumors, as well as non-neoplastic tumor-like conditions, most of which can be diagnosed by light microscopic examination including special stains and more recently immunoperoxidase techniques. Nevertheless there are situations where ultrastructural examination can contribute substantially to an accurate and specific diagnosis. It is my opinion that electron microscopy can be of greatest benefit and is most cost effective when applied in conjunction with other methodologies. Thus, I have developed an approach which has proved useful for me and may have benefit for others. In cases where it is deemed of potential value, glutaraldehyde-fixed material is obtained at the time of frozen section or otherwise at operation. Coordination with the gynecologic oncologist is required in the latter situation. This material is processed and blocked and is available if a future need arises.

Ultrastructure of myoepithelial cell in parotid gland

1988 ◽  
Vol 46 ◽  
pp. 342-343
Author(s):  
C. N. Sun
Keyword(s):  
Parotid Gland ◽  
Osmium Tetroxide ◽  
Individual Cell ◽  
Branching Processes ◽  
Muscle Cells ◽  
Myoepithelial Cells ◽  
Uranyl Acetate ◽  
Thin Sections ◽  
Gland Carcinoma ◽  
Parotid Gland Carcinoma

Myoepithelial cells have been observed in the prostate, harderian, apocrine, exocrine sweat and mammary glands. Such cells and their numerous branching processes form basket-like structures around the glandular acini. Their shapes are quite different from structures seen either in spindleshaped smooth muscle cells or skeletal muscle cells. These myoepithelial cells lie on the epithelial side of the basement membrane in the glands. This presentation describes the ultrastructure of such myoepithelial cells which have been found also in the parotid gland carcinoma from a 45-year old patient.Specimens were cut into small pieces about 1 mm3 and immediately fixed in 4 percent glutaraldehyde in phosphate buffer for two hours, then post-fixed in 1 percent buffered osmium tetroxide for 1 hour. After dehydration, tissues were embedded in Epon 812. Thin sections were stained with uranyl acetate and lead citrate. Ultrastructurally, the pattern of each individual cell showed wide variations.

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