scholarly journals Putative poison gland in the thorny catfish Acanthodoras spinosissimus (Siluriformes: Doradidae)

2021 ◽  
Vol 51 (3) ◽  
pp. 250-254
Author(s):  
Jefferson G. SODRÉ ◽  
Talles R. COLAÇO-FERNANDES ◽  
Lúcia H. RAPP PY-DANIEL ◽  
José L. O. BIRINDELLI ◽  
Jansen ZUANON
Keyword(s):  
Chemical Composition ◽  
Natural Environment ◽  
Histological Analysis ◽  
Poison Gland ◽  
Unique Characteristic ◽  
Secretory Cells ◽  
Ecological Functions ◽  
Remarkable Feature ◽  
Anatomical Structures ◽  
Secretory Products

ABSTRACT Acanthodoras is the only genus of catfish known to secrete a conspicuous and abundant milky-looking substance through an axillary pore located just below the base of the posterior cleithral process. Despite this remarkable feature, there is no published information on the anatomical structures that produce the secretion and its possible biological/ecological functions. Dissection and histological analysis of preserved specimens of A. spinosissimus revealed the presence of a saccular axillary gland with large, binuclear secretory cells, similar to those found in other poisonous catfish. Secretory cells near the lumen appear to lose nuclei and become filled with secretory products, possibly with proteinaceous elements, as indicated by their eosinophilic appearance. As far as we know, the saccular morphology of the gland appears to constitute a unique characteristic of Acanthodoras among Doradidae catfishes. Further studies are necessary to determine the chemical composition of the secretion, as well as its possible uses by the catfish in its natural environment.

Ultrastructure of scent glands in larvae of Apateticus bracteatus (Hemiptera: Pentatomidae) and chemical composition of the secretion

1980 ◽  
Vol 58 (11) ◽  
pp. 2105-2115 ◽  
Author(s):  
Jean Percy ◽  
J. A. MacDonald ◽  
J. Weatherston
Keyword(s):  
Chemical Composition ◽  
Interstitial Cells ◽  
Secretory Cells ◽  
Scent Glands ◽  
Volatile Constituents ◽  
Dorsal Wall ◽  
Anterior Dorsal ◽  
Glandular Cells ◽  
Gland Function ◽  
Dorsal Abdominal Glands

The three dorsal abdominal glands in larvae of Apateticus bracteatus (Pentatomidae) secrete a mixture of compounds. Major volatile constituents of the secretion are identified, herein, as tridecane and 2-octenal. There are also trace amounts of 2-hexenal and two other unidentified compounds.Each of the glands has paired orifices that are located between tergites 3/4, 4/5, and 5/6, but only the most anterior gland is paired. In anterior glands of midinstar larvae, glandular cells associated with ducts, and interstitial glandular cells are distributed along the ventral walls of the reservoirs. In posterior glands, columnar glandular cells are located in the anterior dorsal wall of the reservoirs; secretory cells associated with ducts, and nonglandular interstitial cells are distributed throughout the ventral and posterior walls of the reservoirs. The interstitial glandular cells of the anterior gland and the columnar glandular cells of the middle and posterior glands contain cytoplasmic organelles characteristic of lipid-producing cells. In all glands the secretory cells associated with ducts secrete lipids. Evidence indicating the importance of Golgi and ER in secretion synthesis is presented. The reservoirs and ducts have a thin cuticular lining.The bearing of the results on present ideas of gland function in Heteroptera is discussed.

Ultrastructure of the podia of Amphiura chiajei and Amphiura filiformis and their role in feeding

2006 ◽  
Vol 86 (4) ◽  
pp. 817-822 ◽  
Author(s):  
John K. Keogh ◽  
Brendan F. Keegan
Keyword(s):  
Chemical Composition ◽  
Morphological Study ◽  
Secretory Cells ◽  
Suspension Feeding ◽  
Head Region ◽  
Feeding Styles ◽  
Amphiura Filiformis ◽  
The Difference ◽  
Mucus Cells ◽  
Deposit Feeding

Morphological study of the podia of the suspension feeding Amphiura filiformis and the deposit feeding Amphiura chiajei revealed sensory–secretory complexes in the podial epidermis, consisting of four cells, two secretory and two sensory. Large mucus cells were found in association, but not exclusively, with the sensory–secretory complexes. In A. filiformis, mucus cells stained positively for both acid and neutral mucopolysaccharides, while, in A. chiajei, these cells stained only for acid mucopolysaccharides. The surfaces of the arm podia in A. chiajei were relatively smooth, while the arm podia of A. filiformis bear papillae. The sensory–secretory complexes open through numerous paired pores, with each pair having an intervening cilium. Pores were restricted to the podial tip in A. chiajei, while in A. filiformis they are concentrated on the podial tip and on the papillae. Amphiura chiajei shows very little differentiation of the podia along the length of the arm. In A. filiformis, the distal podia have papillae throughout their entire length, with pores being found on the head region and the papillar tips. Here, the papillae are oriented in such a way (i.e. facing inward towards the ventral arm plate) as to increase the area of the filtering surface of the podium, serviced by the sticky secretions from the sensory–secretory complexes. The proximal podia are relatively simple in structure and are thought to function more in the transportation of mucus wrapped particles to the mouth rather than in their capture. The difference in structure of the podia and chemical composition of podial secretory cells are taken to reflect the difference in feeding styles of the two species.

scholarly journals LYSOSOME FUNCTION IN THE REGULATION OF THE SECRETORY PROCESS IN CELLS OF THE ANTERIOR PITUITARY GLAND

1966 ◽  
Vol 31 (2) ◽  
pp. 319-347 ◽  
Author(s):  
Robert E. Smith ◽  
Marilyn G. Farquhar
Keyword(s):  
Anterior Pituitary ◽  
Dense Body ◽  
Secretory Granules ◽  
Secretory Process ◽  
Secretory Cells ◽  
Residual Body ◽  
Multivesicular Bodies ◽  
Dense Bodies ◽  
Pituitary Glands ◽  
Secretory Products

The nature and content of lytic bodies and the localization of acid phosphatase (AcPase) activity were investigated in mammotrophic hormone-producing cells (MT) from rat anterior pituitary glands. MT were examined from lactating rats in which secretion of MTH1 was high and from postlactating rats in which MTH secretion was suppressed by removing the suckling young. MT from lactating animals contained abundant stacks of rough-surfaced ER, a large Golgi complex with many forming secretory granules, and a few lytic bodies, primarily multivesicular bodies and dense bodies. MT from postlactating animals, sacrificed at selected intervals up to 96 hr after separation from their suckling young, showed (a) progressive involution of the protein synthetic apparatus with sequestration of ER and ribosomes in autophagic vacuoles, and (b) incorporation of secretory granules into multivesicular and dense bodies. The content of mature granules typically was incorporated into dense bodies whereas that of immature granules found its way preferentially into multivesicular bodies. The secretory granules and cytoplasmic constituents segregated within lytic bodies were progressively degraded over a period of 24 to 72 hr to yield a common residual body, the vacuolated dense body. In MT from lactating animals, AcPase reaction product was found in lytic bodies, and in several other sites not usually considered to be lysosomal in nature, i.e., inner Golgi cisterna and associated vesicles, and around most of the immature, and some of the mature secretory granules. In MT from postlactating animals, AcPase was concentrated in lytic bodies; reaction product and incorporated secretory granules were frequently recognizable within the same multivesicular or dense body which could therefore be identified as "autolysosomes" connected with the digestion of endogenous materials. Several possible explanations for the occurrence of AcPase in nonlysosomal sites are discussed. From the findings it is concluded that, in secretory cells, lysosomes function in the regulation of the secretory process by providing a mechanism which takes care of overproduction of secretory products.

Structure, function and secretory products of the peltate glands of Centrolobium tomentosum (Fabaceae, Faboideae)

2012 ◽  
Vol 60 (4) ◽  
pp. 301 ◽  
Author(s):  
Esmeire Cruz Matos ◽  
Élder Antônio Sousa Paiva
Keyword(s):  
Three Dimensional ◽  
Secretory Cells ◽  
Secretory Product ◽  
Vegetative Organs ◽  
Transmission Electron ◽  
Histochemical Tests ◽  
Glandular Structures ◽  
Secretory Products ◽  
Development Structure ◽  
Structure And Ultrastructure

The glandular structures of Centrolobium tomentosum Guill. ex Benth. have been little studied despite the economic importance of this species. We describe here the distribution, development, structure and ultrastructure of the secretory cells of the peltate glands found on the vegetative organs of this species. Stem apices and leaves in various stages of development were collected and prepared for examination by light, scanning and transmission electron microscopy. Chemical analyses and conventional histochemical tests to determine the chemical nature of the secretory products were also carried out. Peltate glands occur on aerial vegetative organs during their primary growth stage. These trichomes are structurally stable, persisting throughout the development of the organ. During the initial stages of the gland development, cell separation creates a central space that expands as secretions accumulate. Maximum secretion rates occur during this phase and the secreting cells characteristically have well developed smooth and rough endoplasmic reticulum, and high numbers of plastids and mitochondria. During the later stages of the secretory phase, the central cells show symptoms of cell death and are incorporated in to the secretions. At trichome maturity, the central space is delimited by a uniseriate epithelium. In addition to the resin, which is the main secretory product, an extensive three-dimensional carbohydrate matrix was observed that extended throughout the central space, apparently giving support to the resin droplets. The terpenic nature of the secretion was confirmed by thin-layer chromatography. Given the terpenic nature of the secretion and the permanence of trichomes throughout all phases of leaf development, it is postulated that the resin-secreting trichomes act to protect the plant against herbivores.

Biomimetics and Biotemplating of Natural Materials

MRS Bulletin ◽  
2010 ◽  
Vol 35 (3) ◽  
pp. 219-225 ◽  
Author(s):  
Oskar Paris ◽  
Ingo Burgert ◽  
Peter Fratzl
Keyword(s):  
Magnetic Properties ◽  
Chemical Composition ◽  
Natural Environment ◽  
Design Principles ◽  
Plant Fibers ◽  
Renewable Source ◽  
Natural Materials ◽  
Artificial Materials ◽  
Hierarchical Structuring ◽  
Direct Use

AbstractNatural materials display a wealth of structures and fulfill a variety of functions. Hierarchical structuring is one of the keys to providing multifunctionality and to adapting to varying needs of an organism. As a consequence, the natural environment represents not only a direct and renewable source of useful materials, such as wood, plant fibers, or even proteins of pharmaceutical importance, but also an enormous “database” of structures with exceptional mechanical, optical, or magnetic properties. Rather than focusing on the direct use of natural materials, this article discusses the use of structures that appeared in evolution and have been implemented in artificial materials of an entirely different type and chemical composition. This may be done either by directly copying the structure (biotemplating) or by extracting the design principles encoded in them for the fabrication of novel bioinspired materials.

scholarly journals Memoirs: Studies on the Golgi Apparatus in Gland-Cells

1926 ◽  
Vol s2-70 (279) ◽  
pp. 419-449
Author(s):  
ROBERT H. BOWEN
Keyword(s):  
Golgi Apparatus ◽  
Secretory Granules ◽  
Secretory Cells ◽  
Animal Cells ◽  
Exact Relation ◽  
Cytological Evidence ◽  
Duplex System ◽  
Secretory Cycle ◽  
Gland Cells ◽  
Secretory Products

As a result of recent studies on secretory synthesis, the following conclusions have been reached : 1. Many gland-cells run through a regular ‘secretory cycle’, beginning with a small cell devoid of secretory granules, progressing through a period in which large numbers of granules are produced and terminating in an act of extrusion of the granules. The cycle may or may not be repeated according to the nature of the cell. 2. The Golgi apparatus is from the beginning present in all kinds of secretory cells, and during the secretory cycle becomes very greatly hypertrophied, establishing a volume in rough relation to that of the secretory products. 3. The topography and behaviour of the apparatus is different in different kinds of glands, but is roughly divisible into three general types characteristic of cells which produce serous, mucous, and lipoidal secretions. 4. The secretory granules make their first appearance only within the area delimited by the Golgi apparatus. 5. In a few cases relations have been made out which indicate that the secretory granules arise in close connexion with the Golgi material. 6. It is concluded that secretory granules are differentiated by the Golgi material, but that no direct transformation of the one into the other occurs such as was claimed by some authors in the case of the mitochondria. 7. It is suggested that the Golgi material is structurally homologous throughout the range of animal cells, and that the so-called idiosomic substance, sometimes associated with it, is to be looked upon as one phase of a duplex system in which the relative development of lipoidal and idiosomic substances may undergo considerable variation. 8. It is suggested that the relation between the Golgi apparatus and secretory granules is homologous to that existing between the Golgi apparatus and the developing acrosome of the animal sperm, and that our rather complete under standing of the latter phenomenon can thus be used as a basis for interpreting the much more obscure phenomena in the gland-cell. 9. No cytological evidence of the origin of secretory products from the nucleus receives any general acceptance at the present time. The nucleus can be considered as the source of secretions only in the indirect sense that it may possibly exercise some control over the process as a whole or may collaborate with other parts of the cell system in preparing materials for the actual synthetic operations of the Golgi apparatus. 10. The establishment of the views here developed must depend finally upon further critical evidence bearing upon the exact relation which exists between individual secretory granules and the Golgi complex.

scholarly journals HORMONE SECRETION BY CELLS DISSOCIATED FROM RAT ANTERIOR PITUITARIES

1973 ◽  
Vol 59 (2) ◽  
pp. 276-303 ◽  
Author(s):  
Colin R. Hopkins ◽  
Marilyn G. Farquhar
Keyword(s):  
Growth Hormone ◽  
Single Cells ◽  
Hormone Secretion ◽  
Cell System ◽  
Secretory Cells ◽  
Mechanical Dispersion ◽  
High K ◽  
Pituitary Secretion ◽  
Secretory Products ◽  
Stimulation Of

A new procedure has been developed for dissociating anterior pituitary tissue and producing a viable suspension of single cells. The procedure involves incubation of small tissue blocks in 1 mg/ml trypsin (15 min), followed by incubation in 8 µg/ml neuraminidase and 1 mM EDTA (15 min), followed by mechanical dispersion. Cell yields are ∼55%, based on recovered DNA. By electron microscopy five types of secretory cells (somatotrophs, mammotrophs, thyrotrophs, gonadotrophs, and corticotrophs) plus endothelial and follicular cells can be identified and are morphologically well preserved up to 20 h after dissociation. Throughout this period, the cells incorporate linearly [3H]leucine into protein for up to 4 h at a rate 90% greater than hemipituitaries, and they synthesize, transport intracellularly, and release the two major pituitary secretory products, growth hormone and prolactin. Immediately after dissociation the cells' ability to respond to secretogogues (high K+ and dibutyryl cyclic AMP) is impaired, but after a 6–12-h culture period, the cells apparently recover and discharge 24% and 52%, respectively, of their content of prelabeled growth hormone over a 3-h period in response to these two secretogogues. This represents a stimulation of 109% and 470% over that released by cells incubated in control medium. The results demonstrate that function and morphologic integrity are preserved in this cell system. Therefore it is suitable for the study of various aspects of pituitary secretion and its control.

Structure of the noncuticular simplex of the internal male reproductive tract of Calpodes ethlius (Hesperiidae, Lepidoptera)

1982 ◽  
Vol 60 (6) ◽  
pp. 1184-1201 ◽  
Author(s):  
J. Lai-Fook
Keyword(s):  
Cellular Structure ◽  
Secretory Cell ◽  
Reproductive Tract ◽  
Secretory Cells ◽  
Apical Region ◽  
Apical Surface ◽  
Male Reproductive Tract ◽  
Circular Layer ◽  
Secretory Products ◽  
Longitudinal Layer

The ductus ejaculatorius simplex (simplex) of the reproductive tract of the adult male of Calpodes ethlius is separated by distinct constrictions into seven segments, varying in length from 0.24 to 19.3 mm and totalling 4 cm. Two of the segments, S1 and S5, are further divisible into three and two parts, respectively, on the basis of either cellular structure or secretory products. The most distinctive region is the most anterior one which is made up of two distinctly different cells, one a merocrine secretory cell which resembles the cells of all other regions, and the other an apocrine secretory cell whose highly modified apical region is sloughed upon copulation. All segments are surrounded by two layers of muscle, a thin, inner circular layer and a more robust, outer longitudinal layer, which are supplied with tracheoles and nerves. Tracheoles also penetrate the epithelium of segment seven. The merocrine secretory cells of all segments are similar in that they all have well-developed endoplasmic reticulum, numerous Golgi and mitochondria, and a microvillate apical surface. Nonetheless, the cells of each segment are distinguished by some feature of either their structure or their secretions.

scholarly journals Trends in the content of acidifying and eutrophying compounds in atmospheric precipitation in an urbanized area

2021 ◽  
Vol 65 (6) ◽  
pp. 724-733
Author(s):  
S. V. Kakareka ◽  
Yu. G. Kokosh ◽  
M. A. Kudrevich
Keyword(s):  
Chemical Composition ◽  
Nitrogen Content ◽  
Natural Environment ◽  
Atmospheric Precipitation ◽  
Experimental Site ◽  
Average Decrease ◽  
Subsequent Period ◽  
Reduced Nitrogen ◽  
Acidification Potential ◽  
Precipitation Acidity

The trends in changing the content of sulfur and nitrogen in atmospheric precipitation in the territory of Minsk over an 18-year period are characterized on the basis of the analysis of the monitoring results of the chemical composition of atmospheric precipitation at the experimental site. A downtrend in the sulfur and nitrogen content combined with an uptrend in the precipitation acidity was identified. An average decrease (trend) in the content of sulfur in atmospheric precipitation for 2002–2019 was 0.019 mg S/dm3/year, of oxidized nitrogen – 0.008 mg/dm3, of reduced nitrogen – 0.019 mg/dm3. Over an 18-year period, the changes in the content of sulfur and nitrogen in atmospheric precipitation decreased the deposition of sulfur on average by 31.3 kg/km2/year, of oxidized nitrogen – by 15.4 kg/km2/year, of reduced nitrogen – by 25.6 kg/km2/year. It is shown that for the period from 2005 to 2012, the acidification potential of the natural environment decreased parallel to the reduction of the sulfur and nitrogen deposition; in the subsequent period, the trend of the acidification potential basically follows the trend of the precipitation of the main cations. It is revealed that the rates of average reduction in the content of oxidized sulfur and oxidized nitrogen in atmospheric precipitation in Minsk for the period from 2002 to 2017 are comparable to the rates of reduction of these compounds at the stations of the EMEP Program in Europe, and exceed those for reduced nitrogen.

scholarly journals Municipal Districts in the System of Landscape-Ecological Zoning of the Northern Sikhote-Alin

2021 ◽  
Vol 895 (1) ◽  
pp. 012015
Author(s):  
E M Klimina ◽  
A V Ostroukhov
Keyword(s):  
Natural Environment ◽  
Sikhote Alin ◽  
Natural Object ◽  
Ecological Functions ◽  
Regional System ◽  
Regional Landscape ◽  
District Government ◽  
Spatio Temporal ◽  
Landscape Ecological

Abstract The process of landscape-ecological zoning of a large natural object makes it possible to represent spatial combinations of geosystems that perform the most important ecological functions. To preserve them at the level of municipal district government, it is necessary to identify ecologically significant landscapes that can be optimally used in the economy and at the same time being part of the regional system for preserving the natural environment. This is a case study of two municipal districts of Khabarovsk Territory – Vanino and Sovetskaya Gavan, their place in the landscape-ecological zoning of the Northern Sikhote-Alin, the dynamics of spatio-temporal changes in the categories of regional landscape-ecological zoning within these districts have been considered.

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