Granules Of Different Electron Densities Research Articles

EFFECT OF SALBUTAMOL ON THE PAROTID SALIVARY GLAND OF RATS: ULTRASTRUCTURAL STUDY

Background: Salbutamol (salb) is a selective β2-adrenergic receptor agonist used for the asthma to relieve bronchospasm. Because of the presence of s2-adrenoceptors in salivary glands, salbutamol may have an effect on salivary composition. This study was carried out to evaluate the effect of Salbutamol on ultrastucture of parotid glands. Materials and Methods: Study group (15 male albino rat) treated with injections of salb, while the control group (15 male albino rat) received saline. Rats were sacrificed at periods of 2 and 7 days of treatment and then one week after stoppage of treatment. The parotid was dissected and processed for transmission electron microscopy.Results: after 2 days, acinar cells of the salb treated glands showed cytoplasmic vacuolization, granules of different electron densities with few electron dense bodies and rough endoplasmic reticulum (RER) with irregularly arranged cisternae. Dense areas of chromatin were observed at the periphery of the nucleus. After 7 days of salb treatment, the nucleus was compressed toward the base of the cell. One week after stoppage of salb, some cytoplasmic alterations still present.Conclusion: short term treatment with salb drug leads to ultrastructural changes of the parotid and some of these changes still present after one week from cessation of the drug.

Anatomy and fine structure of the alimentary canal of the spittlebug Lepyronia coleopterata (L.) (Hemiptera: Cercopoidea)

The alimentary canal of the spittlebug Lepyronia coleopterata (L.) differentiates into esophagus, filter chamber, midgut (conical segment, tubular midgut), and hindgut (ileum, rectum). The filter chamber is composed of the anterior extremity of the midgut, posterior extremity of the midgut, proximal Malpighian tubules, and proximal ileum; it is externally enveloped by a thin cellular sheath and thick muscle layers. The sac-like anterior extremity of the midgut is coiled around by the posterior extremity of the midgut and proximal Malpighian tubules. The tubular midgut is subdivided into an anterior tubular midgut, mid-midgut, posterior tubular midgut, and distal tubular midgut. Four Malpighian tubules run alongside the ileum, and each terminates in a rod closely attached to the rectum. Ultrastructurally, the esophagus is lined with a cuticle and enveloped by circular muscles; its cytoplasm contains virus-like fine granules of high electron-density. The anterior extremity of the midgut consists of two cellular types: (1) thin epithelia with well-developed and regularly arranged microvilli, and (2) large cuboidal cells with short and sparse microvilli. Cells of the posterior extremity of the midgut have regularly arranged microvilli and shallow basal infoldings devoid of mitochondria. Cells of the proximal Malpighian tubule possess concentric granules of different electron-density. The internal proximal ileum lined with a cuticle facing the lumen and contains secretory vesicles in its cytoplasm. Dense and long microvilli at the apical border of the conical segment cells are coated with abundant electron-dense fine granules. Cells of the anterior tubular midgut contain spherical secretory granules, oval secretory vesicles of different size, and autophagic vacuoles. Ferritin-like granules exist in the mid-midgut cells. The posterior tubular midgut consists of two cellular types: 1) cells with shallow and bulb-shaped basal infoldings containing numerous mitochondria, homocentric secretory granules, and fine electron-dense granules, and 2) cells with well-developed basal infoldings and regularly-arranged apical microvilli containing vesicles filled with fine granular materials. Cells of the distal tubular midgut are similar to those of the conical segment, but lack electron-dense fine granules coating the microvilli apex. Filamentous materials coat the microvilli of the conical segment, anterior and posterior extremities of the midgut, which are possibly the perimicrovillar membrane closely related to the nutrient absorption. The lumen of the hindgut is lined with a cuticle, beneath which are cells with poorly-developed infoldings possessing numerous mitochondria. Single-membraned or double-membraned microorganisms exist in the anterior and posterior extremities of the midgut, proximal Malpighian tubule and ileum; these are probably symbiotic.

Ultra-structure and histochemistry of digestive cells of Podisus nigrispinus (Hemiptera: Pentatomidae) fed with prey reared on bt-cotton

The toxic effects of Bt proteins from the body of the prey/host to predators and parasitoids have been investigated as a route of impact on non-target insects of Bt crops. This research aimed to analyze ultrastructural changes and histochemistry in digestive cells of the middle region of the midgut of Podisus nigrispinus fed, since its second instar, with Spodoptera frugiperda reared on Bt cotton variety Acala90 B, which expresses the toxin Cry 1Ac, and its non-Bt isoline Acala 90. Fragments of the midgut of P. nigrispinus were analyzed by electron microscopy. For the histochemical analysis, Bromophenol Blue, Periodic Acid Schiff von Kossa, Alcian Blue pH 2.5 and Sudan Black were used. The Cry1Ac toxin of Bt cotton ingested by S. frugiperda promotes a disorganization in the perimicrovillar matrix of P. nigrispinus (third trophic level), thus generating ultrastructural changes in the digestive cells, as elongation of microvilli, presence of spherocrystals and granules of different electron densities, in addition to altering the distribution pattern of glycogen, lipids and calcium of these cells in the median region of the midgut. Thus, we conclude that species moderately susceptible to Cry1Ac toxin, such as S. frugiperda, can acquire this toxin and expose it to P. nigrispinus, which can interfere with your ability to predation.

Ankara tavşanı ince bağırsağında Paneth hücrelerinin morfolojisi, histokimyası ve ince yapısı üzerinde çalışmalar

Bu araştırma, Ankara tavşanı ince bağırsağındaki Paneth hücrelerinin morfolojisini, histokimyasal özelliklerini, yerleşim bölgelerini ve sayısal dağılımını ortaya koymak amacıyla yapıldı. Çalışmada materyal olarak özel yetiştiricilerden sağlanan 10 adet sağlıklı, erişkin Ankara tavşanının duodenum, jejunum ve ileumlarından alınan doku örnekleri kullanıldı. Lieberhkühn kriptlerinde gözlenen Paneth hücreleri, bazalinde çekirdeği ve apikalindeki asidofilik granülleriyle tanındı. Granüller, Mallory’nin üçlü boyama tekniği, Phloxine-tartrazine, Alcian blue-performik asit ve Mallory’nin fosfotungstik asit-hematoksilen uygulamasına pozitif reaksiyon, Periyodik asit-Schiff (PAS), Alcian blue (pH 2.5), PAS-Alcian blue pH 2.5 boyamalarına ise negatif reaksiyon verdi. Paneth hücrelerinin ince bağırsağın tüm uzunluğu boyunca homojen bir dağılım göstermediği, hücre yoğunluğunun duodenumdan ileuma doğru gidildikçe arttığı gözlendi. İnce bağırsağın üç bölgesi arasındaki farkın istatistiksel olarak önemli olduğu (p<0.01) saptandı. Elektron mikroskobik incelemelerde bazı Paneth hücrelerinin apikal sitoplazmasında elektron yoğun ve homojen granüller, bazılarında ise elektron yoğunlukları farklı olan homojen granüller görüldü

Ultrastructural study of the ovary of the sugarcane spittlebug Mahanarva fimbriolata (Hemiptera)

The present study describes the ultrastructure of meroistic telotrophic ovaries of the sugarcane spittlebug Mahanarva fimbriolata. In this type of ovary, nurse cells, oogonia, and prefollicular tissue are located at the terminal (distal) regions or tropharium of ovarioles. Oocytes in different developmental stages, classified from I to V, are observed in the vitellarium. Stage I oocytes do not exhibit intercellular spaces in the follicular epithelium, suggesting that synthesis and production of yolk during this stage occurs only through endogenous processes. Small yolk granules of different electron densities are present in the cytoplasm. Few lipid droplets are observed. Stage II oocytes exhibit small intercellular spaces in the follicular epithelium. More protein as well as lipid yolk granules are observed in the cytoplasm. In stage III oocytes, intercellular spaces in the follicular epithelium are larger than those observed in the previous stage. Electrondense protein granules of various sizes, larger than those observed in stage II oocytes predominate in the cytoplasm. Smaller lipid droplets are also present. In stage IV oocytes, the follicular epithelium exhibits large intercellular spaces. Our data clearly indicate that the opening of these spaces in the follicular epithelium of M. fimbriolata oocytes increases as the intake of exogenous proteins intensifies, that is, in stages IV and V oocytes. During these stages, granular yolk becomes viscous due to the lysis of granules. In stage V oocytes, viscous yolk predominates in the cytoplasm. This type of yolk, however, has not been described for other orders of insects. The chorion of M. fimbriolata oocytes consists of an external layer (exochorion) and an internal one (endochorion), which is in direct contact with the oocyte. Numerous small pores that probably facilitate oxygenation of the internal structures inside the eggs are observed in the exochorion.

Structure and Ultrastructure of Adrenocorticotropic Hormone Cells in Goats in Anoestrus, Gestation and Milk Production

The structural and ultrastructural characteristics of adrenocorticotropic hormone cells in adult female goats in anoestrus, gestation and milk production were studied with an immunohistochemical method (peroxidase-antiperoxidase). Only one cellular type has been identified and is characterized by numerous secretory granules of different electron density and an average diameter of 275 nm. During pregnancy these cells increase in number and size, and there is a frequent presence of vacuoles. During lactation the number of size of the cells decreases but without reaching the state observed in anoestrus and the involution of the cytoplasmic vacuolizations which appear in pregnancy.

Further Evidence for Synthesis of Screening Pigment Granules Involved in the Photosensory Membrane Turnover of the Crayfish Photoreceptor

Photosensory membrane degradation in crayfish occurs at first in multi-vesicular bodies (MVBs) and then, with the aid of lysosomal enzymes, in lysosome related lamellar bodies. In organ culture experiments with the isolated crayfish retina (Orconectes limosus) small screening pigment-like granules became visible under the electron microscope in such lamellar bodies and suggested a possible relation of photosensory membrane degradation and screening pigment granule synthesis. Chloroquine, an inhibitor of lysosomal activity, when added to the culture medium reduced the appearance of screening pigment-like granules in lamellar bodies, but led to the appearance of these granules in mature MVB's, indicating the involvement of lysosomal enzymes in the formation of pigmented lamellar bodies. In a second set of experiments the effect of bright light on the screening pigment granule ultrastructure of crayfish phoreceptors was investigated. It was found that after bright light exposure large numbers of little screening pigment granules (0.15-0.3 microns) were located between or close to rhabdomeral microvilli that were not at these sites in crayfish kept under natural light. MVB's were also reduced in size, and among the little screening pigmentary organelles granules of different electron density and morphology appeared. Additionally, vesicle flux to little screening pigment granules was detected. The screening pigment granules of the little type did not seem to be transported close to or between the microvilli, but appeared to be synthesized at these sites within little MVBs.

Enteroendocrine APUD cells in the digestive tract of larval Barbus conchonius (Teleostei, Cyprinidae)

The development of Barbus conchonius is described with special attention to the differentiation of the gut. Amine precursor uptake and decarboxylation (APUD) are present in enteroendocrine cells during development, whereas these processes are lacking in adult specimens. The first APUD cells originate on the fourth day of development in the anterior part of the gut and on the fifth day in the caudal areas. The APUD facility of the cells disappears within 2 days, and after the 6th day APUD cells can no longer be distinguished in the intestinal epithelium. The first APUD cells were obsserved when four types of enteroendocrine cells were recognized with the electron microscope. These enteroendocrine cells contain granules of different electron densities, and microtubules and cilia can be observed. Some enteroendocrine-like cells are found below the basement membrane of the intestinal epithelium, indicating a possible extra-endodermal origin. APUD cells, except melanoblasts, have not been found migrating from the neural crest in ventral direction. The origin of the enteroendocrine cells of B. conchonius is discussed.

Fine structure of pars neuro-intermedia of the loach, Misgurnus fossilis L.

Two types of glandular cells are present in the pars intermedia of the loach, Misgurnus fossilis. Basophils are characterized by the presence in their cytoplasm of numerous secretory granules containing electron-dense and homogeneous material and by scarce endoplasmic reticulum. ‘Weak’ acidophils contain in their cytoplasm abundant endoplasmic reticulum and numerous granules of different electron densities.

Ultrastructure and secretory cycle of the gastrin-producing cell

The gastrin-producing cells in the cat have been studied under various experimental conditions indicating the secretory cycle of these cells. Normal gastrin cells in animals fed ad libitum show secretory granules of different electron density. After fasting for 24 hrs the cells are granulated with electron dense secretory granules and after refeeding the cells are degranulated, showing clear secretory granules. The implication of the endoplasmic reticulum and the Golgi apparatus in the secretory cycle is discussed on the basis of the ultrastructural findings.