Crystallization of reptile hemoglobin during its digestion in a pentastomide

The hemoglobin of the lizard Tarentola annularis has been studied within erythrocytes being digested in the gut of a parasitic pentastomide, Raillietiella sp. The hemoglobin is crystallized in the form of bundles comprised of numerous tubules (up to 2000). These tubules are simple or complex. Simple tubules are 50 nm in diameter; their wall is made up of two electron-opaque rings, separated by a clear ring. Complex tubules are up to 100 nm in diameter and show as many as 13 concentric walls. High magnification of transverse sections of simple tubules show 96 granules; each opaque ring is made up of 48 granules. Human hemoglobin is known to crystallize as 18-nm tubules, the wall of which is made up of six molecules; comparison of these data with our observations indicates that transverse sections of tubules of crystallized lizard hemoglobin should contain 24 molecules. Thus, each molecule of crystallized lizard hemoglobin consists of four granules; these granules may be considered as globin molecules. Erythrocytes in fresh lizard blood do not show crystallized hemoglobin; however, in blood treated with sodium bisulfite, they show tubules similar to that found in the parasite.     

Sporogonic Development of the Gregarine Ascogregarina taiwanensis (Lien and Levine) (Apicomplexa: Lecudinidae) in Its Natural Host Aedes albopictus (Skuse) (Diptera: Culicidae)

ABSTRACT. Sexual reproduction of Ascogregarina taiwanensis occurred in pupal Malpighian tubules of its natural host Aedes albopictus , resulting in the formation of gametocysts within which oocysts developed. Sporogony proceeded in each newly formed unsporulated oocyst; eight sporozoites were formed after completion of nuclear divisions followed by the cytokinesis. Developing oocysts were separated by gradient centrifugation on percoll based on different buoyant densities. The slender sporozoite had a typical apical complex composed of a coiled conoid, polar rings, rhoptries with ductules, subpellicular microtubules and micronemes. An apical cavity was seen in the gland-like rhoptries. Mitochondria of gregarines were not seen in any stage during the sporogony. Howeever, amylopectin granules were frequently seen in the cytoplasm. These starch-related granules became scant when the sporozoite was formed. We assumed they were associated with the energy source. Since the apical complex was only present in the sporozoite stage, it was most likely related to the invasion of host epithelial cells of the midgut during the early phase of infection.     

Dissolution of granules in the Malpighian tubules of Musca autumnalis DeGeer,during mineralization of the puparium

The dissolution of mineralized granules stored in the larval Malpighian tubules of the face fly, Musca autumnalis DeGeer, was studied both in situ and with isolated granules in vitro. The release of calcium, phosphorus, and magnesium from granules increased exponentially as the pH of the bathing medium was decreased. The pH measured in the distal region of the Malpighian tubules was 8.08 while that of the proximal region was 7.35. Thus, the decrease in pH of lumen contents from distal to proximal regions of the tubules appears to be a major effector of granule dissolution. Loss of structural integrity of the granules accompanied mineral release and also increased as pH of the bathing medium was lowered in vitro. This structural disintegration was similar to that observed in naturally dissolving granules isolated from the proximal region of the Malpighian tubules. The larval tubules, therefore, appear to have regional specialization in that granules are formed and stored in the distal lumen and dissolution takes place as granules move into the more acidic proximal region. No granules were found in the larval hindgut contents also indicating that dissolution and transport take place in the proximal region of the tubules. However, granules of similar composition were found in the meconium and in the most distal regions of adult Malpighian tubules.     

Corpora Cardiaca-Allata Complex of the Larvae of the Pink Bollworm,Pectinophora gossypiella. An Ultrastructural Study in Relation to Diapause

Raina, A. K., Borg, T. K. 1980. Corpora cardiaca-allata complex of the larvae of the pink bollworm, Pectinophora gossypiella. An ultrastructural study in relation to diapause. (Department of Entomology, North Dakota State University of South Carolina, School of Medicine, Columbia, U.S.A.) — Acta zool. (Stockh.) 61(2): 65–77. The corpora cardiaca (CC) and corpora allata (CA) of the pink bollworm, Pectinophora gossypiella, were studied at the ultrastructural level during induction maintenance, and termination of larval diapause. The CC is composed of 5–6 intrinsic secretory (IS) cells, glial cells, and axons that carry electron dense (ED) and electron lucent (EL) granules from the brain. The IS cells produce ED granules with an average diameter of 110 ± 26 nm. During diapause, the axons with ED granules showed large accumulations of neurosecretory granules, but the axons with the EL granules contained lesser amounts. The CA is made up of approximately 25 large cells and axons that pass through the CC from the brain. Most of the axons take up a peripheral position. A characteristic feature of CA cells during diapause was the presence of stacks of convoluted tubules of the smooth endoplasmic reticulum (SER) that may be associated with juvenile hormone synthesis. The IS cells of the CC appeared to be inactive during diapause.     

Salivary glands of heteromyid rodents, with a summary of the literature on rodent submandibular gland morphology

The principal parenchymal elements of the submandibular glands of the heteromyid rodents Dipodomys merriami, Perognathus longimembris, Perognathus fallax, Perognathus penicillatus and Perognathus baileyi consist of acini, granular tubules and striated ducts. Acinar cells of the four species of Perognathus are aniline blue, PAS (magenta) and Alcian blue (pH 2.5) positive and metachromatic with toluidine blue and safranin. The granules of the tubule cells are orthochromatic and react with aniline blue, orange G, the PAS reagent (deep pink) and the tryptophan indicator, xanthydrol. Acinar and tubule cells of D. merriami exhibit similar reactions except for the Alcian blue stain. Acinar cells of D. merriami do not react with Alcian blue. Submandibular glands of D. merriami exhibit a sexual dimorphism of the granular tubules. There is little observable difference between the sexes in the species of Perognathus but the ratio of granular tubules to acinar elements, the degree of hypertrophy of the tubules, and the amount of mucosubstance and protein (granules) contained in their cells are different in the four species studied. Since these desert rodents have similar habitats and habits, the differences observed between the two heteromyid subfamilies studied, as well as among the four members of a single subfamily, suggest that these are inherent species variations rather than variations of adaptation to environment.     

Ultrastructure of chloride cells in young adults of the anadromous sea lamprey, Petromyzon marinus L., in fresh water and during adaptation to sea water.

The chloride cells in the interlamellar areas of the gills of young adult, anadromous sea lampreys, Petromyzon marinus L., captured in fresh water undergo structural modification during the adaptation of these animals to sea water. In fresh water the chloride cells are partially overlapped by mucus-secreting superficial cells and contain an extensive reticulum of cytoplasmic tubules, which are confluent with both lateral and basal plasma membranes, numerous mitochondria, a Golgi complex of moderate size, and numerous apical vesicles. Adaptation to sea water results in a retraction of the superficial cells, exposing the entire apical surface of the chloride cells, and a proliferation of both cytoplasmic tubules and mitochondria. Extensive enlargement of the Golgi complex in the chloride cells of these animals suggests the involvement of this organelle in the proliferation of cytoplasmic tubules. The extracellular tracer, ruthenium red, enters the tubules from the lateral or basal intercellular spaces in both freshwater- and seawater-adapted animals but never enters either tubules or vesicles from the apical surfaces, indicating that these are not confluent. The presence of dividing basal cells and newly-forming chloride cells, combined with evidence of degeneration of chloride cells, suggests that there is a turnover of this cell type. Both superficial and basal cells are phagocytic and involved in heterophagy of degenerating chloride cells. This phenomenon occurs in both fresh water and sea water indicating that the chloride cells may be functional in both environments.     

Mitochondria-rich (chloride) cells in the gill epithelia from four species of stenohaline fresh water teleosts

Summary The mitochondria-rich (chloride) cells have been found to be present in the gill epithelia of four species of stenohaline fresh water teleosts. The cytoplasm of these chloride cells contains an extensive network of cytoplasmic tubules which communicate with intercellular spaces bordering the lateral and basal cell surfaces. Numerous vesicles with fairly electron-dense interiors are also present in the apical cytoplasm of chloride cells. The apical surface of a chloride cell forms an apical pit, but the lumen of the pit does not appear to be in continuity with the interior of the apical vesicles and tubules inside the cell.When Carassius auratus were kept in 100, 200, 300, and 400 mOsm-diluted sea water for a month, no appreciable changes occurred in the number and fine structure of the chloride cells, except for a dilation of the apical vesicles and a slight decrease in diameter of the cytoplasmic tubules in these cells in the fishes kept in 300 and 400 mOsm.These results suggest that chloride cells may be a rather common occurrence in the gill epithelia of stenohaline fresh water teleosts, and may function in ion-transport in these fishes in fresh water environments.     

Ultrastructure of the ookinetes of Haemoproteus meleagridis (Haemosporina: Haemoproteidae)

Ookinetes of Haemoproteus meleagridis were structurally similar to kinetes of other apicomplexan parasites and possessed a polar ring complex (PRC) composed of an electron-lucent polar ring with 25 supporting tines. Fifty subpellicular microtubules were anchored in a circle to the inner surface of the polar ring. A bilayered electron-dense canopy was continuous with the inner layer of the pellicle and formed a caplike cover over the PRC. Embedded rings of actin-sized microfilaments completely encircled each layer of the canopy. Numerous micronemes, 2 smaller preconoidal rings, and a conoid composed of approximately 6 spirally wound, electron-dense tubules were also present. Other organelles were similar to those reported in previous studies of haemosporidian ookinetes. Mature ookinetes of H. meleagridis developed in the midguts of engorged specimens of Culicoides edeni (Diptera: Ceratopogonidae) within 24 hr after a blood meal. Most parasites were found beneath, or embedded within, a peritrophic membrane composed of fine granules and fibrils. The observation of actin-sized microfilaments within the canopy is a previously unrecognized modification of the pellicle that probably supports the anterior end of ookinetes during penetration of the peritrophic membrane.     

Ultrastructure of the heart of the sturgeon Acipenser stellatus (Chondrostei)

Summary The ultrastructure of atrial and ventricular myocardial cells from Acipenser stellatus is described. The cells of the atrium are more loosely connected than those of the ventricle. Cell contact is by simple intercalated discs and by desmosomes. The cells are flattened, with peripheral myofibrils and a central region of mitochondria and the nucleus. The sarcoplasmic reticulum consists of subsarcolemmal tubules, that frequently extend towards the central mitochondria. Dyads are small and positioned at any sarcomeric level. No T-tubules are present. Specific granules are restricted to the atrial cell, and are sometimes present within the SR tubules.     

Ultrastructure of the principal and accessory submandibular glands of the common vampire bat

The principal and accessory submandibular glands of the common vampire bat, Desmodus rotundus, were examined by electron microscopy. The secretory endpieces of the principal gland consist of serous tubules capped at their blind ends by mucous acini. The substructure of the mucous droplets and of the serous granules varies according to the mode of specimen preparation. With ferrocyanide-reduced osmium postfixation, the mucous droplets are moderately dense and homogeneous; the serous granules often have a polygonal outline and their matrix shows clefts in which bundles of wavy filaments may be present. With conventional osmium postfixation, the mucous droplets have a finely fibrillogranular matrix; the serous granules are homogeneously dense. Mucous cells additionally contain many small, dense granules that may be small peroxisomes, as well as aggregates of 10-nm cytofilaments. Intercalated duct cells are relatively unspecialized. Striated ducts are characterized by highly folded basal membranes and vertically oriented mitochondria. Luminal surfaces of all of the secretory and duct cells have numerous microvilli, culminating in a brush borderlike affair in the striated ducts. The accessory gland has secretory endpieces consisting of mucous acini with small mucous demilunes. The acinar mucous droplets contain a large dense region; the lucent portion has punctate densities. Demilune mucous droplets lack a dense region and consist of a light matrix in which fine fibrillogranular material is suspended. A ring of junctional cells, identifiable by their complex secretory granules, separates the mucous acini from the intercalated ducts. The intercalated ducts lack specialized structure. Striated ducts resemble their counterparts in the principal gland. As in the principal gland, all luminal surfaces are covered by an array of microvilli. At least some of the features of the principal and accessory submandibular glands of the vampire bat may be structural adaptations to the exigencies posed by the exclusively sanguivorous diet of these animals and its attendant extremely high intake of sodium chloride.     

A post-embedding avidin-biotin peroxidase system to demonstrate the light and electron microscopic localization of lectin binding sites in rat kidney tubules

Summary A post-embedding method for the light and electron microscopic demonstration of lectin binding sites in rat kidney tubules is described. The use of biotinylated lectins, followed by treatment with avidin peroxidase and the DAB—H₂O₂ sequence, produced intense staining of acrylic sections at the electron microscope level: brush borders and associated structures, cytoplasmic granules, basal infoldings and basement membrane—plasmalemmal interfaces of proximal tubules bound erythrophytohaemagglutinin, while distal tubules were mainly unstained. At the light microscope level, epoxy resin sections showed a similar staining pattern after etching, as did acrylic resin sections after intensification of the final reaction product. The binding of wheatgerm agglutinin to cytoplasmic granules and brush border structures in the proximal tubules was abolished, at both the light and electron microscope levels, by the competing sugar tri-N—acetylchitotriose. Epoxy resin ultrathin sections required etching before staining was achieved in the electron microscope, and results were far inferior to those obtained with acrylic resin. This method allows rapid and inexpensive screening of large numbers of lectins, if required, at both the light and electron microscope levels, using reagents that are stable for long periods of time.     

Fine structure of the chromatoid body during spermatogenesis in the water-strider,Gerris remigis (SAY)

Summary During spermatogenesis in Gerris remigis, chromatoid bodies appear in the spermatocytes and persist to the-mid-spermatid stage. These structures consist of numerous, parallel tubules, which measure approximately 500 Å in diameter. The tubules are arranged in hexagonal array, and contain dense granules that resemble ribosomes. The chromatoid body may be secretory in function, or may be involved in intracellular transport.The technical assistance of Mr. Roy R. Keppie and Mrs. Mona Brandreth is gratefully acknowledged.     

Unusual cell organelles during spermiogenesis in two species of gobies (Gobiidae,Teleostei)

Summary Testes of Lesuerigobius friesii and Gobius bucchichi were studied in adult reproductive fish. During the onset of spermatid development, a peculiar system of alternating rough (RER) and smooth (SER) endoplasmic reticular tubules form rings distally to the cell nucleus. The RER tubules are seen to possess up to 12 ribosomes in cross-section, whereas the SER are strongly electron-dense. Nanotubules connect these stacks of tubules to the developing head and tail of the sperm. With ripening of the sperm these tubules disintegrate within the excessive cytoplasm. It seems likely that these are special forms of Macro-Golgi System that possibly provide protamines for the developing sperm.     

Atrial natriuretic peptide detected by immunocytochemistry in peripheral organs of Tupaia belangeri

Summary ANP (atrial natriuretic peptide), a peptide found in granules of mammalian atrial cardiac myocytes, has been shown to be active in regulation of blood pressure and body water homeostasis. The existence of ANP in atrium, pituitary, adrenal gland, and kidney of the rat had been immunocytochemically demonstrated with an antibody against rat ANP (102–126). We used the same antibody in immunocytochemical studies for the detection of ANP in peripheral organs of the tree shrew (Tupaia belangeri). The antibody stained granules in myocytes of cardiac atria which indicated that it reacted with tree shrew ANP. In contrast to the rat, no immunoreactive cells were found in pituitaries and adrenal glands. However, in the kidneys distal tubules in outer medulla and cortex were labeled Ascending limbs of distal tubules were intensely stained when either the peroxidase-antiperoxidase (PAP) or the indirect immunofluorescence method were used. Collecting ducts and convoluted distal tubules in the outer cortex showed a granular type of staining when the immunofluorescence method was used. These data indicate that ANP is present in epithelial cells of distal tubules and collecting ducts, where it may be involved in the regulation of renal salt excretion.     

Characterization of the Adhesive from Cuvierian Tubules of the Sea Cucumber <Emphasis Type="Italic">Holothuria forskali</Emphasis> (Echinodermata,Holothuroidea)

Abstract Sea cucumbers possess a peculiar specialized defense system: the so-called Cuvierian tubules. The system is mobilized when the animal is mechanically stimulated, resulting in the discharge of a few white filaments, the tubules. Their great adhesivity, combined with their high tensile strength, allows Cuvierian tubules to entangle and immobilize potential predators. The cellular origin and composition of the Cuvierian tubule adhesive were investigated in the species Holothuria forskali by studying prints left on the substratum after mechanical detachment of the tubule. Polyclonal antibodies raised against tubule print material were used to locate the origin of tubule print constituents in the tubules. Extensive immunoreactivity was detected in the secretory granules of mesothelial granular cells, suggesting that their secretions make up the bulk of the adhesive material. Tubule print material consists of 60% proteins and 40% carbohydrates, a composition that is unique among the adhesive secretions of marine invertebrates. Although it is highly insoluble, a small fraction of this material can be extracted using denaturing buffers. Electrophoretic analysis of the extracts revealed that it contains about 10 proteins with apparent molecular masses ranging from 17 to 220 kDa and with closely related amino acid compositions, rich in acidic and in small side-chain amino acids. The adhesive from the Cuvierian tubules of H. forskali shares these characteristics with many marine bioadhesives and structural biomaterials.     

Location of copper in larvae of Plectrocnemia conspersa (Curtis) (Trichoptera) exposed to elevated metal concentrations in a mine drainage stream

Using histological techniques together with transmission electron microscopy and X-ray microanalysis, copper-containing granules (which also contain significant amounts of sulphur) have been observed in the cells of the malpighian tubules and in the subcuticular region of larvae of Plectrocnemia conspersa. It is suggested that the granules in both these regions are primarily pigment granules, which provide a mechanism for taking potentially toxic concentrations of copper (and possibly other metals) out of circulation. This mechanism of metal tolerance may in part account for the reported occurrence of larvae of P. conspersa in waters with elevated concentrations of trace metals.     

Gross,histological and ultrastructural morphology of the aglomerular kidney in the lined seahorse Hippocampus erectus

Histologic evaluation of the renal system in the lined seahorse Hippocampus erectus reveals a cranial kidney with low to moderate cellularity, composed of a central dorsal aorta, endothelial lined capillary sinusoids, haematopoietic tissue, fine fibrovascular stroma, ganglia and no nephrons. In comparison, the caudal kidney is moderately to highly cellular with numerous highly convoluted epithelial lined tubules separated by interlacing haematopoietic tissue, no glomeruli, fine fibrovascular stroma, numerous capillary sinusoids, corpuscles of Stannius and clusters of endocrine cells adjacent to large calibre vessels. Ultrastructural evaluation of the renal tubules reveals minimal variability of the tubule epithelium throughout the length of the nephron and the majority of tubules are characterized by epithelial cells with few apical microvilli, elaborate basal membrane infolding, rare electron dense granules and abundant supporting collagenous matrix.     

The ultrastructure of the posterior midgut caecum of Pachygrapsus crassipes (Decapoda, Brachyura) adapted to low salinity

The effects of salinity adaptation and of composition and tonicity of fixatives upon the ultrastructure of the posterior midgut caecum (PMC) of Pachygrapsus crassipes have been studied. The PMC epithelium consists of a single layer of columnar cells with a microvillous border. The apical cytoplasm contains numerous mitochondria, lysosomes, and much smooth endoplasmic reticulum. Rough endoplasmic reticulum and Golgi apparatus are situated in the perinuclear cytoplasm. This epithelium resembles other transporting epithelia in that the basal cytoplasm has an extensive system of branched tubules formed from invaginations of the lateral and basal plasma membrane. Numerous mitochondria are associated with the basal tubular system. To determine the possible contribution of the PMC to the osmoregulatory ability of Pachygrapsus, the ultrastructure of the PMC from animals adapted to 40, 50, 100 and 150% sea water was investigated. Enlargement of basal tubules and intercellular spaces at low salinity, suggestive of fluid-transport activity, was found to be an artifact of fixation. The most consistent response when animals were acclimated to dilute salinities was that some basal mitochondria assume a more complex shape, usually appearing as rings in cross sections of the caecum. A hypothesis concerning the functional significance of these mitochondria is proposed.     

Secretory activity of the segmented Malipighian tubules of Cenocorixa bifida (Hung.) (Hemiptera,Corixidae)

In vitro studies with whole Malpighian tubules of the water boatman Cenocorixa bifida show that the composition of the secreted fluid is similar to that reported in several other insects. All three distal segments of the tubule are secretory, but the rate of fluid, sodium, potassium and chloride contribution is greatest in the short, most distal segment (IV). The sodium, potassium, and chloride concentrations of fluid produced by segments II, III, and IV change sequentially in a gentle stepwise gradient; osmotic pressure does not change significantly. Segment II produces fluid with a high pH under cAMP stimulation thus raising the pH of fluid produced by the whole tubule. Segment III is the site of dye transport and the production of luminal secretory granules. Possible correlations between the morphology and transport properties of the different segments are discussed.     

The fine structure of daphnid supraesophageal and optic ganglia,and its possible functional significance

Neurosecretory activity and fine structure of the supraesophageal and optic ganglia of Daphnia schødleri Sars were studied. The relative amount of paraldehyde fuchsin stainable material present was determined at “daylight” and at one and three hours following for animals maintained under photoperiods of 7.5, 10.5, 13.5, and 16.5 hours. More material was found after one hour in both ganglia and there was a tendency for more in the optic ganglion under 7.5- and 10.5-hour photoperiods. Sections made at two levels in the supraesophageal ganglion and one level in the optic ganglion were examined with an electron microscope. Posterior and anterior parts of the supraesophageal ganglion contain apparent nerve processes at the edge of the ganglion, parallel to the anterior-posterior axis; these have large granules. Neurons in both areas contain patches of presumed polysaccharide granules. In the posterior region are a dorsolateral and a ventrolateral glandular cell, presumably these occur on both sides of the brain. They have very well-developed endoplasmic reticulum and some large granules. The dorsal cell is usually at the tip of a glial attenuation. Concentric lamellar systems are located in dilated nerve processes of the first optic ganglion neuropile. Large whorls (about 3.5 μ) are composed of concentric lamellae. When lamellae do not form complete rings, they end in loops or in dilated tubules that are sometimes constricted as vesicles. Small whorls (1.5 μ) typically have lamellae joined into two or three thick layers. Mitochondria are frequently associated with the whorls. It is proposed that the whorls are active in synthesis, possibly neurohumor production.