Cysticercus bovis: pinocytosis in the Cysticercus tegument

The authors have found that pinocytosis occurs in the tegument of C. bovis from the fourth week after infection. Electron-lucid bladders surrounded by plasma membrane were encountered in the distal cytoplasm. The pinocytosis occurred in form of micropinocytotic bladders only in the bladder tegument but not in the scolex. The bladders appeared first in the superficial part of the distal cytoplasm. During the following periods of development of the larva they were dispersed in the whole distal cytoplasm and were found even in the processes of subtegumental cells and inside these cells near the heterolysosomes.     

Histochemistry of the parenchyma of Cysticercus bovis.

The contents of mucosubstances, proteins and lipids, and the activity of several enzymes were studied in the parenchyma of the bladder wall and the invaginated portion of Cysticercus bovis aged 108 days. The parenchyma of both parts contained a large amount of glycogen and minute bodies with a high activity of acid phosphatase and non-specific esterase. By contrast to older larvae, the young larvae contained a minute amount of hydrophobic lipids. The rostellum was developed and similar to the suckers contained glycogen.     

Tissue reaction to Cysticercus bovis in the lung of artificially infected cattle

The tissue reaction to Cysticercus bovis in the lung of cattle with an experimental infection was an inflammatory rim originating in the immediate vicinity of the cysts. The cysts recovered at days 83 and 102 p.i. contained living cysticerci. The rim was composed either of a layer of high histiocytes organized in palisades (at day 83 p.i.), or a lyer of flat histiocytes (at day 102 p.i.). The outer layer of the rim consisted of fibroblasts, reticular cells and a different number of eosinophil- and neutrophil luekocytes. On the periphery, the rim was formed by granulation tissue infiltrated with lymphoplasmocytes. At the border between the layers of the inflammatory rim there were conspicuous foci of a necrotic appearance typical of a tissue reaction to C. bovis.     

Morphological and histochemical demonstration of hooks in the rostellar region of Cysticercus bovis.

Hooklets and early developmental stages of hooks were discovered in the tegument among the microtriches in the rostellar region of 83- and 108-day-old Cysticercus bovis. The cortical layer of hooks consists of proteins with tyrosine and SS groups. The rostellar sac and bulb are distinctly developed in the parenchyma of the rostellar region.     

Morphological determination of the age of Cysticercus bovis in very young calves with cysticercosis.

Characteristics and measurements are given for early developmental stages of Cysticercus bovis. The data emerging from our study indicate that the age of a one to two month-old larva from a spontaneous infection can reliably be determined in histological sections. On these grounds we have been able to determine that the cysticercus infection in the two calves (aged 21 and 27 days respectively) had been acquired prenatally.     

Tissue reaction in the heart of cattle with a spontaneous and artificial Cysticercus bovis infection.

Results of detailed studies on tissue reactions to Cysticercus bovis in the heart of cattle, together with a comparison of findings in animals with spontaneous and experimental infection, and an evaluation of tissue reactions in relation to the location, morphology and morphogenesis of C. bovis provided evidence for the fact that in general, the response of the heart to the presence of C. bovis was an inflammatory reaction characterized by the origin of a pseudoepithelial border and a zone of granulation tissue. Later, when necrotic changes started to affect the cysticercus, the inflammatory reaction started to develop anew. It was accompanied by an exudation and a subsequent resorption. Characteristic features were focal necroses both of the exudate and the inflammatory border followed by a dystrophic calcification, focal necroses and a dystrophic calcification of individual collagenous fibres and groups of these fibres in addition to a regular appearance of necrotic-like foci typical of a reaction to C. bovis. The location of the cysticercus in a certain part of the lymphatic system of the heart and in skeletal muscles was shown to have a considerable effect on the course of the inflammatory reaction. Differences in the development of the inflammatory reaction explained concomitant findings of dead and live cysticerci at the same time after an experimental infection.     

Pathology of experimental Cysticercus bovis infection in the reindeer (Rangifer tarandus Linné, 1758)

In the present study, the tissue reaction of the brain, skeletal muscles and heart in experimental C. bovis infection of the reindeer is described. There is non-purulent cysticercal leptomeningites with formation of multinucleate symplasms in the cerebral meninges, and lymphocytic encephalitis in the superficial layers of the cerebral cortex. The tissue reaction around the morphologically differentiated cysticercus in the meningeal location is similar to that in muscle cysticercosis of cattle. In muscles and heart, larvae die very soon after infection and they are resorbed in the course of formation of fibroplastic granulation tissue around them. C. bovis reaches the infective stage in cerebral localization only. The authors suppose that this phenomenon is due to a certain degree of immunological tolerance in the brain.     

Histochemistry of the racemose form of Cysticercus cellulosae.

The racemose form of brain cysticercosis arises from an intense proliferation of the bladder wall after the scolex part has degenerated. The proliferating zones are 2-3 times thicker than the remaining parts of the bladder and are characterized by a densely folded tegument and thick subtegumental and parenchymal layers. The tegument and subtegumental cells contain a large amount of acid mucosubstances with sulpho groups and hydrophilic lipids, and exhibit a high activity of alkaline and acid phosphatases. The parenchyma contains a large amount of glycogen. With the gradual aging of the bladder wall and with the first signs of autolysis, the enzymatic activity as well as the amounts of glycogen, neutral and acid mucosubstances, and proteins decrease, and the hydrophobic lipids prevail over the hydrophilic ones. The results obtained are important for the differential diagnostics of cestode larval stages in the human brain.     

Histochemistry and fine structure of the bladder tegument of a larval Multiceps endothoracicus

Certain differences were found in the histochemistry and fine structure of an active bladder tegument of an infective larva of M. endothoracicus and a regressively changing bladder of an aging larva of this species. The bladder tegument of an aging larva contained an accumulation of acid mucosubstances and phospholipids, that of a younger larva neutral mucosubstances, and it reacted less strongly than the former to tyrosine, cystine and tryptophane. Evidence was obtained with the scanning (SEM) and transmission (TEM) microscope for regressive changes in the bladder of an aging larva: its microtriches were more slender, less tightly packed and fibrously interconnected, and there were spherical formations adhering to the microthrix border. Sometimes, the vacuolation of rod-shaped bodies was so much advanced that these bodies looked like vacuoles arising to the surface of the distal cytoplasm. Another sign of bladder regression was the formation of vacuoles in the cytoplasm of subtegumental cells with contents of a granular to crystalline structure.     

Ultrastructural study of the glandular system and its participation in tegument formation in Echinostoma revolutum cercaria

Six types of gland cells occurring in the body of developing Echinostoma revolutum cercaria are described at ultrastructural level. Three types of the gland cells, lateral, ventral and dorsal, release their secretion into the tegument of cercaria during its development in the media. Another three types, paraoesophageal, penetration and proper cytogenic gland cells are preserved in the body of the free-swimming cercaria. The paraoesophageal gland cells open on the tegument surface. Secretory granules of all types of gland cells and stratification of the body tegument arising by gradual release of the contents of the above mentioned three types of gland cells are characterized in detail.     

On the regularities of distribution of Hypoderma bovis De Geer larvae parasitizing cattle herds in different parts of the range of this warble fly.

The type and parameters of the distribution of the second and third instar larvae of Hypoderma bovis in cattle herds in Czechoslovakia (54 herds, 7233 head), Mongolia (20 herds, 1809 head) and the USSR (48 herds, 4978 head) were studied. A statistical analysis showed a) that in the majority of cases negative binomial distribution serves as a model of the distribution of larvae with sufficient reliability; b) that the regularity of dependence of the distribution exponent k of the negative binomial distribution on the incidence of infestation remains constant in different parts of the range of this warble fly. The latter fact indicates that the regulatory systems limiting the population numbers of this warble fly are associated with host-parasite relationships and do not depend on a complex of conditions specific for various natural zones. In order to understand the regulatory processes in parasite populations it is necessary to study equally the regulatory mechanisms operating primarily on the level of specimens as well as the regulatory systems operating on the level of populations.     

Ultrastructure of the forebody and foregut tegument and eccrine gland cells of Crepidostomum metoecus (Trematoda: Digenea: Allocreadiidae)

The forebody and foregut of Crepidostomum metoecus Braun, 1900 are invested with a tegument bearing regularly arranged surface tubercles comparable with the aspidogastrean surface structures. The tegument of the ventrolateral lobes and of the prepharynx is penetrated by ducts of eccrine gland cells. The frontal and prepharyngeal gland cells, localised in the parenchyma, discharge electron-dense granules. Their ducts are lined by peripheral microtubules and fixed to the tegument plasmalemma by a septate junction. The functional roles of these glands are discussed.     

The fine structure and histochemistry of bleb-like extrusions in the microthrix border of the larval Multiceps endothoracicus.

The study on the fine structure and the histochemistry of microtriches in the spiral canal and the scolex of a larva of the polycephalic cestode Multiceps endothoracicus suggested a defensive mechanism of a part of the parasite against invading cells of the parasite against invading cells of the tissue reaction of the host. Numerous vesicles and bleb-like extrusions were present in the transitory zone of the opening of the spiral canal and in the rostellar region of the scolex in close contact with deteriorating host cells. Both, the vesicles and bleb-like extrusions gave a positive reaction for SS and SH groups and displayed an enzymatic activity of acid phosphatase (AP) and nonspecific esterase (NE). Scanning and transmissive electron microscopy revealed the process of formation of bleb-like extrusions from the distal cytoplasm and showed that the appearance of the microtriches was being changed by an accumulation of products of secernation and secretion responsible for a lysis of the host cells.     

Comparative studies on the morphology, histology, and histochemistry of metacestodes (Hymenolepididae, Dilepididae and Dipylidiidae)

Histological and histochemical methods were used for the studies on 12 species of metacestodes of the genera Coronacanthus, Diorchis, Diplopylidium, Fimbriaria, Hymenolepis, Microsomacanthus, Rodentotaenia, and Triodontolepis. Two basic types of larvae, cysticercoid and cercoscolex, were found. The cyst structure is identical or similar in the cysticercoids using the same group of intermediate hosts (gammarus, planktonic crustaceans, coprophagous beetles, and terrestrial snails). The morphological structure of scolex and neck is the same as in adult cestodes. The length and number of hooks are definitive in morphologically differentiated metacestodes, while the scolex, rostellum and suckers grow still inside the definitive host. The excretory canals open separately at the end of neck in the cysticercoids and in a common opening at the body end of larva in the cercoscolex. Calcareous corpuscles are smaller and more numerous in the scolex and neck than in the cyst wall. Acid mucosubstances prevail in the tissues at the early stages of development. In morphologically differentiated metacestodes, the amount of neutral mucosubstances and glycogen increases. In ageing larvae, the amount of neutral mucosubstances and glycogen gradually decreases and later also decreases the amount of acid mucosubstances, proteins and lipids.     

Morphology, histochemistry and ultrahistochemistry of special verrucose formations in daughter sporocyst of Eurytrema pancreaticum

Verrucose formations were found on the surface of fully developed sporocysts of E. pancreaticum Janson, 1889 at the site where the attenuated proboscis-like anterior portion widens into the posterior portion. Under these verrucose formations is always a group of gland cells. Their narrowed processes pass at a common site through the muscle layer and above this layer again slightly widen and project above the neighbouring tegument. The tegument of the verrucose formation differs from the neighbouring tegument of the sporocyst. In the cytoplasm of the gland cells there are large, spherical membrane-bound bodies containing proteins with tryptophan, tyrosine and SH groups. These bodies do not have any activity of alkaline phosphatase, acid phosphatase or nonspecific esterase. Besides these protein bodies the perinuclear cytoplasm is filled with beta glycogen particles and many cisternae of endoplasmic reticulum. The processes of these cells contain thick fibriles. The verrucose formations with the gland cells seem to serve for attachement and lysis. This function is applied not only during the development of the sporocyst, but also during its release from the site of location and penetration through the snail tissue.     

On the ontogeny of the fungus spore

Fungus spores can be borne endogenously in sporangia, gametangia or asci, or exogenously on basidia, conidiophores or sporogenic cells. Exogenous spores can be produced by sprouting (blastospores), by fission (arthrospores) or by an intermediate manner (sprouting followed by fission). This has to be considered especially in the classification of the imperfect fungi.Samenvatting Schimmelsporen kunnen zowel endogeen als exogeen ontstaan. Cellen met een endogene sporevorming heten sporangia. Wanneer aan de sporevorming een reductiedeling vooraf gaat, worden de sporogene cellen asci genoemd. Exogene sporevorming geschiedt door afgrenzing door middel van een celwand (arthrosporen en aleuriosporen) of door knopvorming of wel spruiting (blastosporen).Hiertussen komen overgangen voor: na een knopvorming kan het knopgedeelte zich van de moedercel afgrenzen door een dwarswand. Er wordt voorgesteld bij de indeling van de imperfecte fungi met dergelijke tussenvormen rekening te houden, zoals dit bij de indeling van de gisten geschiedt. Basidiosporen zijn blastosporen die na een reductiedeling op een gespecialiseerde moedercel ontstaan.     

On the anti-cholinesterase activity of benomyl

The fungicide benomyl, previously reported to be an anti-cholinesterase and toxic to earthworms, has now been shown to have little or no effect on cholinesterase. However, it breaks down to form two products: butyl isocyanate. which is an irreversible inhibitor of the enzyme of comparable potency to organophosphates; and methyl benzimidazol-2-ylcarbamate (MBC, carbendazim), which does not inhibit at all. The reported inhibitory power of benomyl is therefore likely to be due to formation of small quantities of the former. It is also concluded that toxicity of benomyl and MBC to earthworms cannot be due to inactivation of cholinesterase.