Ultrastructure and sites of tetranitro-blue tetrazolium reduction of Lactobacillus casei

1968 ◽  
Vol 14 (8) ◽  
pp. 823-827 ◽  
Author(s):  
Joseph P. Brown ◽  
Mercedes R. Edwards ◽  
Paul J. VanDemark
Keyword(s):  
Plasma Membrane ◽  
Normal Control ◽  
Electron Micrographs ◽  
Lactobacillus Casei ◽  
Reduction Product ◽  
Lactobacillus Species ◽  
Blue Tetrazolium ◽  
Ultrathin Sections ◽  
Ultrastructural Characteristics ◽  
Tetrazolium Reduction

Cells of two strains of Lactobacillus casei incubated for 2–10 h in the presence of tetranitro-blue tetrazolium (TNBT) and mannitol were studied in electron micrographs of ultrathin sections. The reduction product tetranitro-blue diformazan (TNBF) was found to be predominantly associated with the plasma membrane and its derivatives. Untreated cells (normal control), as well as cells incubated with mannitol in absence of TNBT (dye control), or with omission of mannitol (substrate control) displayed ultrastructural characteristics, in general, similar to those previously reported for other Gram-positive bacilli, particularly Lactobacillus species.

The Identification of Phospholipid Micelles in Glutaraldehyde-Urea Embedded Tissue

1975 ◽  
Vol 33 ◽  
pp. 494-495
Author(s):  
Daniel C. Pease
Keyword(s):  
Electron Micrographs ◽  
Lung Tissue ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Type Ii ◽  
Lead Citrate ◽  
Phospholipid Micelles ◽  
Type Ii Pneumocytes ◽  
Ultrathin Sections ◽  
Polar Water

It is reasonable to think that phospholipid micelles should be visible and identifiable in electron micrographs of ultrathin sections if only they can be preserved throughout the embedding process. The development of highly polar, water-containing, aminoplastic embedments has made this a likely possibility. With this in mind, an investigation of the lecithin-secreting, Type II pneumocytes of the lung is underway.Initially it has been easiest to recognize phospholipid micelles in lung tissue fixed first with glutaraldehyde, and then secondarily exposed to osmium tetroxide. However, the latter is not a necessary concomitant for micellar preservation. Conventional uranyl acetate and lead citrate staining is finally applied. Importantly, though, the micelles have been most easily seen in tissue embedded in 507. glutaraldehyde polymerized with urea, as described in detail by D.C. Pease and R.G. Peterson (J. Ultra- struct. Res., 41, 133, 1972). When oriented appropriately, the micellar units are seen as tiny, bilayer plates.

Characterization of the structural inclusions in the latex of banana (Musa sp.)

1986 ◽  
Vol 64 (11) ◽  
pp. 2591-2601 ◽  
Author(s):  
J. Kallarackal ◽  
P. R. Garlick ◽  
J. A. Milburn
Keyword(s):  
Plasma Membrane ◽  
Analytical Methods ◽  
Colloidal Suspension ◽  
Nuclear Materials ◽  
Unit Membrane ◽  
Banana Plant ◽  
Musa Sp ◽  
Ultrastructural Characteristics ◽  
Hexagonal Crystals

Because of the importance of latex in indicating the water relations of the banana plant, the structural inclusions in the latex have been examined using microscopic, cytochemical, and analytical methods. Banana latex is a colloidal suspension of diverse organelles. The major organelles have been identified as lipid globules, lutoids, and cytoplasmic fragments. A few raphides and threadlike inclusions were also found. The lipid globules were comparatively large and most of them had an electron-opaque crust around them. The lutoids occurred in two morphologically different forms: globular vesicles and crystalloid vesicles. They were osmotically active and a maximum number of them were in the expanded state when the solute potential of the suspending medium was approximately −0.5 MPa. They had a unit membrane around them and various membraneous structures inside. The crystalloid lutoids had long hexagonal crystals inside them. Some of the globular lutoids had nuclear materials in them. The cytoplasmic fragments occurred as globular structures with a plasma membrane around them. They had granular contents and showed the derivation of vesicles from the plasma membrane. From their staining and ultrastructural characteristics, it is believed that the lutoids have vacuolysosomal activity.

scholarly journals THE AXON HILLOCK AND THE INITIAL SEGMENT

1968 ◽  
Vol 38 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Sanford L. Palay ◽  
Constantino Sotelo ◽  
Alan Peters ◽  
Paula M. Orkand
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Granular Material ◽  
Internal Structure ◽  
Electron Micrographs ◽  
Initial Segment ◽  
Special Function ◽  
Structural Features ◽  
Dense Layer ◽  
Axon Hillock

Axon hillocks and initial segments have been recognized and studied in electron micrographs of a wide variety of neurons. In all multipolar neurons the fine structure of the initial segment has the same pattern, whether or not the axon is ensheathed in myelin. The internal structure of the initial segment is characterized by three special features: (a) a dense layer of finely granular material undercoating the plasma membrane, (b) scattered clusters of ribosomes, and (c) fascicles of microtubules. A similar undercoating occurs beneath the plasma membrane of myelinated axons at nodes of Ranvier. The ribosomes are not organized into Nissl bodies and are too sparsely distributed to produce basophilia. They vanish at the end of the initial segment. Fascicles of microtubules occur only in the axon hillock and initial segment and nowhere else in the neuron. Therefore, they are the principal identifying mark. Some speculations are presented on the relation between these special structural features and the special function of the initial segment.

scholarly journals ON THE THICKNESS OF THE UNIT MEMBRANE

1963 ◽  
Vol 17 (2) ◽  
pp. 413-421 ◽  
Author(s):  
Toshiyuki Yamamoto
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Electron Micrographs ◽  
Synaptic Vesicles ◽  
Multivesicular Bodies ◽  
Unit Membrane ◽  
Cell Organelles ◽  
Membrane Unit ◽  
Nuclear Membranes ◽  
Golgi Vesicles

Peak-to-peak distances between two dense lines of the unit membranes of cell organelles were measured on electron micrographs. These distances were compared with corresponding measurements on the plasma membrane and assigned a percentage value. The comparison between organelle and plasma membrane was always carried out with the same negative, in order to exclude as far as possible errors due to differences in focus or other causes. It was revealed by this study that the membranous structures of the cell can be classified into two groups, one thicker and one thinner. Unit membranes of the thicker group (synaptic vesicles, vesicles and capsules of multivesicular bodies, Golgi vesicles) were not significantly different in thickness from the plasma membrane. Unit membranes of the thinner group (mitochondria, nuclear membranes, Golgi lamellae, endoplasmic reticulum), however, were between 85 and 90 per cent of the thickness of the plasma membrane.

Calcium Enriched Plasma Membrane-Associated Amorphous Deposits in Chondrocytes of Calcifying Cartilage

1980 ◽  
Vol 38 ◽  
pp. 580-581
Author(s):  
W.J. Dougherty
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Alveolar Bone ◽  
Matrix Vesicles ◽  
Conclusive Evidence ◽  
Energy Dispersive ◽  
Fixed Tissue ◽  
Tissue Samples ◽  
Proliferative Zone ◽  
Ultrathin Sections

In previous studies on rat and mouse alveolar bone and rat incisor mantle predentin, amorphous-appearing deposits approximately 5 to 35 nm in diameter were seen to be associated with matrix vesicles in each of these mineralized tissues and with the plasma membranes of osteoblasts and young odontoblasts. It was concluded that these membrane-associated amorphous appearing deposits (MAADs) were mineral because of (1) their inherent electron density in gl utaraldehyde-only fixed tissue and (2) their extract-ability from ultrathin sections by neutral solutions of EDTA (ethylene diamine tetraccetic acid) and EGTA (ethylene glycol bis-(β-aminoethyl ether) N,N1-tetracetic acid). Distilled water and 50% ethanol failed to extract the MAADs from ultrathin sections. While these observations are indicative, they do not offer conclusive evidence for the mineral nature the MAADs. It was considered important to demonstrate the presence of Ca in the deposits by non-destructive analytical methods and to show that these deposits occurred in other calcifying tissues. For these purposes, tibial epiphyses of young growing rats were prepared for routine electron microscopy and energy-dispersive x-ray analysis in the STEM mode of a JE0L-100-CX using previously published procedures (Dougherty, 1978). Ultrathin sections of gl utaral dehyde/osmi urn tetroxide fixed tissue samples were viewed unstained. Figure 1 shows a low magnification TEM image of two chondrocytes in the proliferative zone of the tibial epiphyseal plate. MAADs are present. Figure 2 illustrates in a STEM image at higher magnification two MAADs on another chondrocyte in the proliferative zone. The energy dispersive spectra of point C (an MAAD) and point E (plasma membrane lacking an MAAD) are illustrated in figures 3 and 4. It can be seen that the MAAD at point C is enriched in Ca, while point E is lacking in Ca. Other MAADs on other chondrocytes were enriched in Ca also. Thus, it can be concluded that the MAADs are mineral in nature and that they occur in another major calcifying tissue. It is possible that the MAADs represent the initial nucleation centers in calcifying tissues.

Antimicrobial Activity of some Lactobacillus Species against Intestinal Pathogenic Bacteria

2017 ◽  
Vol 65 ◽  
pp. 10-15 ◽  
Author(s):  
Hamid Tebyanian ◽  
Afsaneh Bakhtiari ◽  
Ali Karami ◽  
Ashraf Kariminik
Keyword(s):  
Antimicrobial Activity ◽  
Lactobacillus Casei ◽  
Pathogenic Bacteria ◽  
Intestinal Flora ◽  
Inhibition Zone ◽  
Enteric Pathogens ◽  
Shigella Dysenteriae ◽  
Lactobacillus Bulgaricus ◽  
Lactobacillus Species ◽  
De Man

Probiotics have antibacterial effects against pathogenic bacteria in the gut while maintaining the balance of intestinal flora such as Lactobacillus. This study aimed to evaluate the antimicrobial activity of four Lactobacillus species against intestinal pathogenic. Four different species of Lactobacillus (Lactobacillus bulgaricus (PTCC 1332), Lactobacillus casei (PTCC 1608), Lactobacillus plantarum (PTCC 1058) and Lactobacillus Fermentum (PTCC 1638)) were experimented to investigate the inhibitory activity against 4 bacterial enteric pathogens (Escherichia coli, Staphylococcus aureus, Shigella dysenteriae and Salmonella paratyphi A) which were separately inoculated in MRS medium (de Man, Rogosa and Sharpe medium) for 48 hours at 37 °C and pH 7. Our results showed that enteropathogens growth was stopped in the presence of all Lactobacillus and inhibition zone was between 12 and 32 millimeter. It can be concluded that these four Lactobacillus strains had potential antimicrobial compounds against human enteric pathogens and should be further studied for their human health benefits.

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