scholarly journals VARIATIONS IN THE STRUCTURE OF MITOCHONDRIA

1956 ◽  
Vol 2 (4) ◽  
pp. 305-312 ◽  
Author(s):  
E. W. Dempsey
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Internal Structure ◽  
Outer Wall ◽  
The Other ◽  
Metabolic Processes ◽  
Intracellular Membranes ◽  
Janus Green ◽  
Definition Of ◽  
Shape Complexity

A characteristic internal structure, consisting of a double-layered outer wall enclosing a matrix-filled space through which pass double-layered membranous folds, would appear to comprise as satisfactory a definition of mitochondria for electron microscopy as their intravital affinity for Janus green affords for light microscopy. Relying for identification upon this characteristic internal structure, mitochondria appear to be pleomorphic structures which vary in size, shape, complexity, and density. They are labile also in that their number may increase or decrease under controlled conditions. The possibility therefore exists that these organelles are constantly being formed and destroyed, perhaps by their participation in metabolic processes. The problem of the origin of mitochondria is in an unsatisfactory state. New organelles unquestionably are formed in particular physiological states. The possibility that new bodies are produced by fission of ones already present does not seem adequate. On the other hand, the possible fabrication of new mitochondria out of intracellular membranes, although an attractive hypothesis, has not been adequately substantiated.

Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

1987 ◽  
Vol 45 ◽  
pp. 1002-1005
Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Light Microscopy ◽  
Colloidal Gold ◽  
Light Microscope ◽  
Ultrastructural Localization ◽  
The Other ◽  
Quantitative Studies ◽  
Dense Suspension ◽  
Antigen Localization

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

Problems associated with ageing squid from their statoliths: towards a more structured approach

1994 ◽  
Vol 6 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Marek R. Lipinski ◽  
M. Deon Durholtz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Regression Analysis ◽  
Light Microscopy ◽  
The Other ◽  
Etching Solution ◽  
Significant Difference ◽  
Structured Approach ◽  
Fish Otoliths ◽  
Scanning Electron

It appears that squid statoliths cannot yet be regarded as accurate an ageing tool as fish otoliths. Statoliths from the same pair, prepared differently for viewing and counting increments, were compared. Increment counts do not imply age in days, because this was not validated. One statolith from each pair was examined by light microscopy (LM) after preparation following a new method. The other was viewed by Scanning Electron microscopy (SEM) with a modified etching solution. Shape of each statolith was similar when compared by multiple regression analysis (11 variables, n=53). There was a weak but significant difference between sexes (statoliths of females were slightly larger). All other differences were insignificant. Microscopic observation and increment counts of increments were successfully carried out for 37 pairs of statoliths. Significant differences between two independent counts were found for the LM method, but no significant differences were found between two independent SEM counts. Counts were significantly different when interpreted by both LM and SEM, probably because of poor resolution in the LM readings and over-resolution (growth layers prominent and numerous) in those read by SEM. Recommendations are made on how ageing studies, based on statoliths, should be structured and the results evaluated.

Pollen morphology of Sabinaria magnifica (Cryosophileae, Coryphoideae, Arecaceae)

Phytotaxa ◽  
2015 ◽  
Vol 207 (1) ◽  
pp. 135 ◽  
Author(s):  
Giovanni Raul Bogota ◽  
Carina Hoorn ◽  
Wim Star ◽  
Rob Langelaan ◽  
Hannah Banks ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
The Other ◽  
Transmission Electron ◽  
Palm Species ◽  
Scanning Electron

Sabinaria magnifica is so far the only known species in the recently discovered tropical palm genus Sabinaria (Arecaceae). Here we present a complete description of the pollen morphology of this palm species based on light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We also made SEM-based comparisons of Sabinaria with other genera within the tribe Cryosophileae. Pollen grains of Sabinaria magnifica resemble the other genera in the heteropolar, slightly asymmetric monads, and the monosulcate and tectate exine with perforate surface. Nevertheless, there are some clear differences with Thrinax, Chelyocarpus and Cryosophila in terms of aperture and exine. S. magnifica differs from its closest relative, Itaya amicorum, in the exine structure. This study shows that a combination of microscope techniques is essential for the identification of different genera within the Cryosophileae and may also be a necessary when working with other palynologically less distinct palm genera. 

Silica deposition in the inflorescence bracts of wheat (Triticum aestivum). I. Scanning electron microscopy and light microscopy

1988 ◽  
Vol 66 (5) ◽  
pp. 829-838 ◽  
Author(s):  
M. J. Hodson ◽  
A. G. Sangster
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Triticum Aestivum ◽  
Light Microscopy ◽  
Triticum Aestivum L ◽  
The Other ◽  
Deposition Pattern ◽  
Membranous Structure ◽  
Silica Deposition ◽  
Scanning Electron

Silica deposition in the lower glume, lemma, and palea of wheat (Triticum aestivum L. cv. Highbury) was investigated using scanning electron microscopy and light microscopy. Silica was present in the outer walls of all the epidermal cells including prickles and papillae of the glume and lemma awns. The glume and the lemma were similar in epidermal silica deposition pattern, both having numerous silicified short trichomes and papillae on inner and outer surfaces. Epidermal long cells and short cells were also silicified. Macrohairs were restricted to isolated areas in these bracts, particularly on the inner surfaces just beneath the awns. The palea was a thin membranous structure differing markedly from the other two bracts. Most of the palea is pressed between the caryopsis and the next floret, and both surfaces are almost devoid of trichomes in these areas. However, at the apex and margins of the palea, macrohairs and papillae were abundant. The results are discussed with respect to possible taxonomic, anatomical, medical, and archaeological implications.

Oncocytoma of the larynx

1990 ◽  
Vol 104 (4) ◽  
pp. 346-349 ◽  
Author(s):  
Anthony C. Robinson ◽  
Antonios Kaberos ◽  
Phillip M. Cox ◽  
Michael P. Stearns
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
World Literature ◽  
Histopathological Diagnosis ◽  
True Vocal Cord ◽  
Accurate Definition ◽  
Thyroid Glands ◽  
The World ◽  
Adequate Surgery ◽  
Definition Of

AbstractA case of oncocytoma of the larynx is presented. These lesions are rarely found in the larynx, and have been more commonly described in the salivary and thyroid glands. The histopathological diagnosis is often difficult and the light microscopy can be unreliable for oncocytic lesions. For a more accurate definition of these tumours, the use of histochemical stains together with electron microscopy are advocated. With adequate surgery, the prognosis is excellent, and tumours are unlikely to recur. This paper discusses the management of a patient with a benign oncocytoma of the true vocal cord, and presents a review of the world literature.

Fine Structure of Bacteria Grown in the Presence of Acriflavine

1968 ◽  
Vol 26 ◽  
pp. 70-71
Author(s):  
Edwin S. Boatman
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Yeast Extract ◽  
Bacterial Growth ◽  
Bacterial Species ◽  
The Other ◽  
Yeast Extract Medium ◽  
Peptone Water ◽  
Extract Medium

The effect of acridine derivatives on bacterial growth has been shown to be dependent upon the concentration used, pH, temperature, and the position of the amino substituents on the acridine molecule. These factors, in turn, affect the amount of acridine bound to cell constituents. Many bacterial species, when grown in media containing acridities, become filamentous, or pleomorphic, or growth may be entirely prevented. The fine-structure of two species of bacteria treated with acriflavine was investigated. Both were Gram-positive bacilli, one was a Corynebacterium, and the other an aerobic spore-bearing Bacillus.Organisms were incubated at 21°c in the presence of concentrations of acriflavine ranging from 0.25 ug/ml to 12 ug/ml in phosphate buffered peptone water yeast extract medium at pH 7.5. Viable counts were carried out and the amount of acriflavine bound, either reversibly or irreversibly, was estimated at 450 mu, using a DB spectrophotometer. Cultures were observed by light microscopy and, after four days growth, were processed for electron microscopy by fixation in veronal-acetate pH 6.1 buffered 0.8% Os O4 for one hour and embedding in Epon 812 resin.

scholarly journals Spinnerets and silk-producing system of Segestria senoculata (Araneae, Araneomorphae, Segestriidae)

2016 ◽  
Vol 48 (3) ◽  
pp. 388 ◽  
Author(s):  
S. Karschová ◽  
J. Hajer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Current Knowledge ◽  
The Other ◽  
Sem Study ◽  
First Time ◽  
Scanning Electron

The spinning apparatus and silk of <em>Segestria senoculata</em> were studied with the use of scanning electron microscopy and light microscopy, which confirmed the presence of four categories of spigots connected with four types of spinning glands (<em>i.e</em>., <em>Glandulae ampullaceae major, Glandulae ampullaceae minor, Glandulae piriformes and Glandulae pseudaciniformes</em>). New data about the morphology of spinnerets and spigots were obtained for both the adults and nymphal stages of both sexes. For the first time the silken threads of retreats, signal threads and attachment discs of the members of <em>Segestria</em> were subjected to a detailed SEM study. The data resulting from studying the spinning apparatus of <em>S. senoculata</em> was compared to current knowledge of the silk producing systems of families belonging to the Dysderoidea superfamily. Silks that are emitted from spigots in the course of retreat construction are not (similarly to the other dysderoids) processed by the spider’s legs during the subsequent process of hardening. Apart from the major ampullate glands/spigots, segestriids also possess developed minor ampullate glands. Minor ampullate threads are used by <em>S. senoculata</em> spiders when making their signal threads.

Pozycja ustrojowa parlamentu finlandzkiego Eduskunty

2019 ◽  
Vol 1 ◽  
pp. 145-162
Author(s):  
Viktoria Serzhanova
Keyword(s):  
Internal Structure ◽  
Structure Functions ◽  
Precise Definition ◽  
The Other ◽  
Basic Law ◽  
Form Of Government ◽  
Rules Of Procedure ◽  
The Subject ◽  
The Moment ◽  
Definition Of

The hereby paper takes up the analysis of the constitutional position of the Finnish parliament Eduskunta from the moment of its establishment and as a result of its development during the centuries, with a special attention paid to the present normative state and on the basis of the hitherto constitutional practice. It aims at deriving the origin and presenting the evolution of this authority at the Finnish lands, which in consequence leads to reliable conclusions in the scope of determining its current constitutional position in the system of the supreme state authorities of Finland. The subject of the paper focuses on the analysis of the beginnings of Eduskunta’s formation and Finnish parliamentarianism, its further evolution, current composition, internal structure, functions and competences presented on the basis of the exegesis of the provisions of the binding basic law of 1999 and the parliament’s rules of procedure. The constitutional principles referring to the parliament and the analysis of Eduskunta’s relations with the other supreme state authorities, which determine the state’s form of government, seem to be of particular significance in this context, as they contribute to a more precise definition of Eduskunta’s constitutional position, as well as to pointing out its originality and dissimilarity regarding other contemporary democratic states.

Somatic mitosis in Erysiphe graminis hordei

1972 ◽  
Vol 18 (12) ◽  
pp. 1915-1922 ◽  
Author(s):  
W. E. McKeen
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Nuclear Membrane ◽  
Osmium Tetroxide ◽  
Central Body ◽  
Nuclear Division ◽  
Light And Electron Microscopy ◽  
Erysiphe Graminis ◽  
The Other ◽  
Erysiphe Graminis Hordei

Somatic nuclear division in Erysiphe graminis hordei was studied by light and electron microscopy after various fixation and staining procedures. Electron microscopy studies of alcohol – acetic acid fixed material aided in providing an understanding of nuclear division and showing the gross alterations which occurred. Light microscopy indicated that a central body was always present at a specific site on the nuclear membrane in the interphase nucleus and was connected to chromatic spherical bodies. Microtubules were preserved when a short glutaraldehyde – osmium tetroxide fixation was used. Some microtubules extend from plaque to plaque while others terminate in kinetochores. A microtubular spindle, oblique to the nuclear and mildew-cells axes formed within the nuclear membrane. Typical prophases, metaphases, anaphases, and telophases were observed. Then one set of daughter chromatids bypassed the nucleolus which persisted intranuclearly until the daughter nuclei reached their destination, and the other set of daughter chromatids moved to midpoint in the other daughter cell. A narrow corridor, which connected daughter nuclei for some time, was filled mainly with microtubules and probably was the filament which was observed in the nucleus by light microscopy during nuclear division. At least six chromosomes were present in each nucleus.

Pollen morphology of the Myrtaceae. Part 4: tribes Kanieae, Myrteae and Tristanieae

2012 ◽  
Vol 60 (3) ◽  
pp. 260 ◽  
Author(s):  
Andrew H. Thornhill ◽  
Geoff S. Hope ◽  
Lyn A. Craven ◽  
Michael D. Crisp
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Pollen Morphology ◽  
The Other ◽  
Pollen Types ◽  
Scanning Electron

Pollen morphology of 44 genera and 101 species from the Myrtaceae tribes Kanieae, Myrteae and Tristanieae was surveyed using scanning electron microscopy (SEM) and light microscopy (LM). Most Myrteae pollen were brevicolpate and granulate, which is unique within Myrtaceae, and these are most likely ancestral characters for this tribe. Two main pollen types were observed in tribe Kanieae, one form being with syncolpate colpi and a distinctive granulate exine, and the other with parasyncolpate colpi and a less ornamented exine. Genera Tristania and Thaleropia of tribe Tristanieae produce the smallest pollen in Myrtaceae, whereas Octamyrtus of tribe Myrteae produces the largest pollen observed in Myrtaceae.

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