Ultrastructural study of the adrenocortical homologue in freshwater and seawater adapted eels

1978 ◽  
Vol 36 (2) ◽  
pp. 586-587
Author(s):  
Tapan Kumar Bhattacharyya ◽  
David Gordon Butler
Keyword(s):  
Fine Structure ◽  
Experimental Studies ◽  
Mature Female ◽  
American Eel ◽  
Endocrine Organ ◽  
The North ◽  
Metabolic Role ◽  
Silver Eels ◽  
Cacodylate Buffer

The teleost fishes have been extensively utilized to explore the biochemical nature of adrenocortical steroids, pathways of steroidogenesis and the metabolic role of adrenocortical steroids. The adrenocortical homologue (AH) has been localized in more than two hundred species of teleosts, although the fine structure of teleost AH has been studied only in the goldfish. It seemed to be of interest to investigate the normal fine structure of this endocrine organ in another zoologically important teleost species, the north American eel (Anguilla rostrata) as a baseline for experimental studies. This animal being a euryhaline species, the AH ultrastructure of animals exposed to artificial seawater for a long period (1 1/2 years) was also examined.Mature female silver eels held in freshwater(FW) and seawater(SW) aquaria were anesthetized and perfused with glutaraldehyde in phosphate buffer or formaldehyde-glutaraldehyde in cacodylate buffer, and glutaraldehyde containing 0. 2% digitonin for demonstration of cholesterol.

Muscle as an Endocrine Organ: Focus on Muscle-Derived Interleukin-6

2008 ◽  
Vol 88 (4) ◽  
pp. 1379-1406 ◽  
Author(s):  
Bente K. Pedersen ◽  
Mark A. Febbraio
Keyword(s):  
Skeletal Muscle ◽  
Interleukin 6 ◽  
Skeletal Muscles ◽  
Insulin Action ◽  
Endocrine Effects ◽  
Endocrine Organ ◽  
Metabolic Role ◽  
Gp130 Receptor ◽  
Health And Disease

Skeletal muscle has recently been identified as an endocrine organ. It has, therefore, been suggested that cytokines and other peptides that are produced, expressed, and released by muscle fibers and exert paracrine, autocrine, or endocrine effects should be classified as “myokines.” Recent research demonstrates that skeletal muscles can produce and express cytokines belonging to distinctly different families. However, the first identified and most studied myokine is the gp130 receptor cytokine interleukin-6 (IL-6). IL-6 was discovered as a myokine because of the observation that it increases up to 100-fold in the circulation during physical exercise. Identification of IL-6 production by skeletal muscle during physical activity generated renewed interest in the metabolic role of IL-6 because it created a paradox. On one hand, IL-6 is markedly produced and released in the postexercise period when insulin action is enhanced but, on the other hand, IL-6 has been associated with obesity and reduced insulin action. This review focuses on the myokine IL-6, its regulation by exercise, its signaling pathways in skeletal muscle, and its role in metabolism in both health and disease.

The fine structure of sporogony in Myxidium zealandicum (Protozoa: Myxosporidia)

1977 ◽  
Vol 55 (2) ◽  
pp. 438-447 ◽  
Author(s):  
W. C. Hulbert ◽  
M. P. Komourdjian ◽  
T. W. Moon ◽  
J. C. Fenwick
Keyword(s):  
Fine Structure ◽  
Germ Cell ◽  
North American ◽  
Polar Capsule ◽  
Anguilla Rostrata ◽  
Transport Function ◽  
American Eel ◽  
The North ◽  
Spherical Structures ◽  
Asynchronous Maturation

Studies of the ultrastructure of the trophozoite (plasmodium) and the process of sporogony and polar capsule development of Myxidium zealandicum from gill and kidney of the North American eel Anguilla rostrata are described. Although the basic steps and characteristics of sporogony are similar to those previously reported for other myxosporidians, we report three new and significant observations in this study: (1) the identification of a uninucleate germ cell for the binucleate sporocyst; (2) the asynchronous maturation of polar capsules within a single sporocyst; and (3) the existence of a mitochondrial layer at the periphery of the Plasmodium that may have a transport function. We also observed cylindrical and spherical structures, either of which might be the primordium of the polar capsule, but we were unable to resolve this problem. These observations are discussed with reference to previous descriptions of myxosporidians.

scholarly journals Metabolic role of visceral adipose tissue and main methods of its diagnosis at the present stage

2020 ◽  
Vol 82 (1) ◽  
Author(s):  
G.D. Fadieienko ◽  
Ya.V. Nikiforova
Keyword(s):  
Adipose Tissue ◽  
Visceral Adipose Tissue ◽  
Biologically Active ◽  
Inflammatory Infiltration ◽  
Endocrine Organ ◽  
Metabolic Functions ◽  
Metabolic Role ◽  
Visceral Adipose ◽  
Active Substances

A review of the literature on the metabolic role of visceral adipose tissue and the main methods for its diagnosis is presented. Visceral adipose tissue is an active endocrine organ what secretes a number of biologically active substances. With an increase in the proportion of visceral adipose tissue, moderate inflammation is observed with a chronic systemic increase in the activity of adipokines. Adipokines carry out several immune or metabolic functions associated with inflammatory infiltration. Active substances such as leptin, adiponectin, resistin, etc., the source of which is visceral adipose tissue, have peripheral, central and local effects on the metabolism of glucose and lipids, glycolysis processes in the liver, etc. It is the activity of visceral adipose tissue that should be considered among the main pathophysiological development factors obesity and its potential metabolic cardiovascular and/or liver complications.

Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

1990 ◽  
Vol 48 (3) ◽  
pp. 68-69
Author(s):  
Alan N. Hodgson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Seminal Vesicle ◽  
Reproductive Biology ◽  
Light Microscope ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

The Inherited Past of the Broch: On Antiquarian Discourse and Contemporary Archaeology

2002 ◽  
Vol 24 (1) ◽  
pp. 1-20 ◽  
Author(s):  
ANDREW BAINES
Keyword(s):  
Material Culture ◽  
19Th Century ◽  
Academic Language ◽  
Contemporary Archaeology ◽  
The North

In reading archaeological texts, we expect to be engaged in a characteristically archaeological discourse, with a specific and recognisable structure and vocabulary. In evaluating the published work of 19th Century antiquarians, we will inevitably look for points of contact between their academic language and our own; success or failure in the identification of such points of contact may prompt us to recognise a nascent archaeology in some writings, while dismissing others as naïve or absurd. With this point in mind, this paper discusses the written and material legacies of three 19th Century antiquarians in the north of Scotland who worked on a particular monument type, the broch. The paper explores the degree to which each has been admitted as an influence on the development of the broch as a type. It then proceeds to compare this established typology with the author's experiences, in the field, of the sites it describes. In doing so, the paper addresses wider issues concerning the role of earlier forms of archaeological discourse in the development of present day archaeological classifications of, and of the problems of reconciling such classifications with our experiences of material culture.

Training of Village Teachers in Vilna Educational District in the 1860s and 1870s

2020 ◽  
Vol 58 ◽  
pp. 181-192
Author(s):  
Anna A. Komzolova
Keyword(s):  
Educational Reform ◽  
Rural Teachers ◽  
Cultural Brokers ◽  
The North ◽  
Central Russia ◽  
Russian Intelligentsia ◽  
Trained Teachers ◽  
The Village ◽  
North Western

One of the results of the educational reform of the 1860s was the formation of the regular personnel of village teachers. In Vilna educational district the goal was not to invite teachers from central Russia, but to train them on the spot by establishing special seminaries. Trained teachers were supposed to perform the role of «cultural brokers» – the intermediaries between local peasants and the outside world, between the culture of Russian intelligentsia and the culture of the Belarusian people. The article examines how officials and teachers of Vilna educational district saw the role of rural teachers as «cultural brokers» in the context of the linguistic and cultural diversity of the North-Western Provinces. According to them, the graduates of the pedagogical seminaries had to remain within the peasant estate and to keep in touch with their folk «roots». The special «mission» of the village teachers was in promoting the ideas of «Russian elements» and historical proximity to Russia among Belarusian peasants.

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

Helping when desire is low: The role of Expectancy in helping

2020 ◽  
Author(s):  
Małgorzata Kossowska
Keyword(s):  
Experimental Studies ◽  
Helping Behavior ◽  
Perceived Effectiveness ◽  
Do So

One might assume that the desire to help (here described as Want) is the essential driver of helping declarations and/or behaviors. However, even if desire to help is low, helping behavior may still occur if the expectancy regarding the perceived effectiveness of helping is high. We tested these predictions in a set of three experimental studies. In all three, we measured the desire to help (Want) and the Expectancy that the aid would be impactful for the victim; in addition, we manipulated Expectancy in Study 3. In Studies 1 and 3, we measured the participants’ declaration to help while in Study 2, their helping behavior was examined. In all three studies, we used variations of the same story about a victim. The results supported our hypothesis. Thus, the studies help to tease apart the determinants of helping behavior under conditions of lowered desire to do so, an issue of great importance in public policymaking.

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