Daughter Sporocysts Research Articles

Effect of Xiphidiocercarial Infection on the Activities of Glycolytic and Oxidative Enzymes in Lymnaea luteola

The activities of aldolase, malate dehydrogenase, cytochrome oxidase, and NADH oxidase were studied in the foot, mantle, and digestive gland of the freshwater gastropod, Lymnaea luteola, infected with xiphidiocercaria of Prosthogonimus sp. The aldolase:MDH ratio was reduced in all three tissues of infected snails. The overall decrease of NADH oxidase in all the infected tissues and the significant reduction of cytochrome oxidase activity in the infected digestive gland might lead to the accumulation of NADH. It was concluded that the TCA cycle probably was activated in order to supply organic acids that can be utilized either by the host or by the parasite. Marshall et al. (1974) demonstrated in- creased levels of several glycolytic enzymes in the parasitized digestive gland of the proso- branch Littorina saxatilis, and Mengebier and Wood (1967, 1969) reported reduced ac- tivities of glycolytic and oxidative enzymes in infected Crassostrea virginica. Though Mc- Manus and James (1975a, b) studied the in- termediary metabolism of the gastropod host, Littorina saxatilis, separate from parasites, their main concern was to compare the en- zyme systems and metabolic pathways be- tween the digestive gland of the host and the daughter sporocysts of Microphallus similis. They showed that the distribution of the Krebs cycle enzymes was similar both in the host digestive gland and the daughter sporo- cysts. Studies on Lymnaea luteola revealed that the adenylate pool size and the oxidation of substrates were altered in infected Lymnaea luteola (Narayanan and Venkateswara Rao, 1978a, b). Therefore, study of changes in the activity profiles of the enzymes catalyzing im- portant metabolic steps seems warranted. Such changes in Lymnaea luteola infected

Infectivity of a microsporidium of mosquitoes ( Nosema algerae) to larval stages of Schistosoma mansoni in Biomphalaria glabrata

Lai P. F. and Canning E. U. 1980. Infectivity of a microsporidium of mosquitoes ( Nosema algerae) to larval stages of Schistosoma mansoni in Biomphalaria glabrata. International Journal for Parasitology 10: 293–301. Nosema algerae derived from a closed colony of Anopheles stephensi was fed to Biomphalaria glabrata infected with Schistosoma mansoni. Mother and daughter sporocysts became hyperinfected but the snail tissues remained free of the microsporidia except for rare small aggregates of spores. These lay close to the sites occupied by mother or daughter sporocysts and were probably liberated from them. Irrespective of dose, fewer snails contained infected sporocysts when spores were given at 7 days post-miracidial infection than when given at 14 days. These periods corresponded respectively to stages when mother sporocysts only or daughter sporocysts as well were present in the snails. Infection of the sporocysts began in the tegumental cells, spread to the brood chamber and ultimately to the cercariae themselves. Heavily infected sporocysts contained fewer developing embryos. Doses of 10 6 and 10 7 spores/snail caused significant depression of cercaria output when given at 14 days but not at 7 days.

Cercaria vaullegeardi Pelseneer, 1906 (Digenea: Hemiuridae); the daughter sporocyst and emergence of the cercaria

SUMMARYThe daughter sporocyst of Cercaria vaullegeardi has hitherto been regarded as occurring within the haemocoel of the digestive gland of Gibbula umbilicalis. A re-examination has shown that an important part of the sporocyst, previously overlooked, extends from the digestive gland, through the afferent renal vein, the right kidney haemocoel and the transverse pallial vessel into the blood channel within a gill filament, thus providing a means of exit from the host directly into the mantle cavity. The sporocyst is described at light and electron microscope levels, and the emergence of the cystophorous cercariae is discussed.

Emergence of the cercariae of Gorgoderina vitelliloba from daughter sporocysts

The daughter sporocyst of Gorgoderina vitelliloba develops attached to the gills of its molluscan host, Pisidium. It has a conical attachment structure at one end of its body through which the birth pore opens. Cercariae emerge through the birth pore, their passage being apparently lubricated by copious secretions from the stylet glands. Only after emergence does the anterior tail chamber envelop the cercarial body to form the typical cystocercous cercaria. When sporocysts were freed from gill tissue and maintained in vitro, cercariae failed to escape from the sporocyst and several encysted, in situ. It is suggested that if this occurred naturally a different host range would be encountered and the long term result might be the evolution of a new species.

The development of daughter sporocysts inside the mother sporocyst ofSchistosoma mansoni with special reference to the ultrastructure of the body wall

The development of the mother sporocyst and the differentiation of the daughter sporocyst of Schistosoma mansoni in Biomphalaria pfeifferi are described. The tegumental structure of the mother sporocyst, consisting of an outer layer connected to internally situated nucleated cell bodies, forms extensions which enwrap the germinal cells. The parenchyma cells, in which the germinal cells were embedded before, degenerate. When daughter sporocyst embryos develop from germinal cells they are enveloped by a primitive epithelium which is formed by fusion of the extensions of the tegumental structure of the mother sporocyst. Somatic cells located peripherally in the developing daughter sporocyst expand and coalesce beneath the primitive epithelium to form the future outer layer of the tegumental structure of the daughter sporocyst. The primitive epithelium degenerates, the newly-formed layer looses its nuclei, and becomes connected to internally situated nucleated cell bodies. Further developments in the tegumental structure of the daughter sporocyst include the formation of microvillus-like projections, a surface coat, spines, and a basement membrane.

Pathology and host responses induced by Schistosomatium douthitti in the freshwater snail Lymnaea catascopium

Most Schitosomatium douthitti miracidia penetrated the esophageal wall of Lymnaea catascopium without provoking amoebocyte encapsulation responses or extensive pathological changes. Amoebocytes frequently attached to developing mother and daughter sporocysts, but did not encapsulate or destroy them. Pressure resulting from extensive growth of mother sporocysts ruptured the transverse membrane of some snails. After releasing daughter sporocysts, mother sporocysts in some snails were destroyed by amoebocytes. Many migrating cercariae became trapped in the tissues of L. catascopium, particularly in the posterior portion of the foot, and were encapsulated and destroyed. Large increases in numbers of amoebocytes in the anterior portion of the lung roof of infected snails were noted, even before cercarial production had been initiated. Atrophy of the digestive gland occurred in infected snails.

Schistosome sporocyst-killing amoebae isolated from Biomphalaria glabrata

Explants and swabs from the pericardium and mantle of three strains of Biomphalaria glabrata, two of them resistant to infection with Schistosoma mansoni, have yielded small amoebae, 3–5μm in diameter, in culture. These amoebae have been grown axenically through > 50 passages to date. The amoebae form cysts in dense cultures. When mixed with S. mansoni mother sporocysts in vitro, the amoebae adhere to and kill the trematodes within several hours. For 1–2 days thereafter, the amoebae proliferate rapidly at a generation time of about 5 hr, then return to normal growth. Sonically disrupted sporocysts also induce proliferation. Live sporocysts do not attract the amoebae or emit soluble substances which influence amoebal growth. Amoebae also adhered to and killed S. mansoni daughter sporocysts and cells derived from B. glabrata embryos; however, they did not harm S. mansoni cercariae or rediae of other trematode species. The proportion of mantle explants yielding amoebae was significantly higher ( P<0.05) in one of the resistant snail strains than in the susceptible strain; however, whether amoebae contribute to snail resistance is unknown. Exposure of snails to S. mansoni miracidia did not influence the proportion of snails yielding amoebae.

Normal Development of Schistosomatium douthitti in the Snail Lymnaea catascopium

Schistosomatium douthitti miracidia are ingested by Lymnaea catascopium snails and penetrate the host's esophageal wall. Mother sporocysts develop adjacent to the esophagus and salivary glands. The increase greatly in size, become irregular in shape, and contain daughter sporocysts by 8 days. Development of daughter sporocysts is synchronous; most are released from mother sporocysts 16--20 days postexposure. Mother sporocysts then collapse, but may persist for the life of the infected snail. Some daughter sporocysts travel to the digestive gland via the arterial system; others traverse the connective tissue separating cephalopedal and visceral sinuses to reach the digestive gland. Cercarial embryo production begins while daughter sporocysts are still within mother sporocysts, and may continue for over 400 days. Once released from daughter sporocysts, cercariae move from the visceral sinus to the visceral vein and are carried into the mantle where they rupture the ventral mantle epithelium and escape from the molluscan host.

The Ultrastructure of the Daughter Sporocyst Tegument of Cercaria vaullegeardi Pelseneer (Digenea, Hemiuridae)

The body wall of the daughter sporocyst of Cercaria vaullegeardi Pelseneer, 1906 is unusual for a species without a birth pore in consisting of an outer anucleated, microvillous syncytial tegument and a cellular subtegument which lacks secretory cells. In contrast, most other known daughter sporocysts without birth pores have a nucleated region above the microvillous region of the tegument. The significance and functional aspects of this structure are discussed.

The morphology ofCercaria cerastodermaeI nom. nov. (Monorchiidae) (=Cercaria lepidapedon rachion(Cobbold, 1858)sensuLebour, 1908) a rare digenean parasite of the cockle in Britain

Summary The mother sporocyst, daughter sporocyst, cercaria and metacercaria of Cercaria cerastodermae I nom. nov. are described from the haemocoel of the digestive gland and gonad of Cerastoderma edule (L.) in Britain. The daughter sporocyst is unusual in having elaborate subtegumental projections that join a central broad chamber which extends to surround individual metacercariae.

The Life History and Biology of Plagioporus hypentelii Hendrix 1973 (Trematoda: Opecoelidae)

Plagioporus hypentelii utilizes the pleurocerid snail, Leptoxis (Mudalia) carinata, as first intermediate host. Effects of snail sex and age are noted on the daughter sporocyst burden. Males, as well as 1- and 2-year-old snails have significantly higher intensities of infection. Cotylomicrocercous cercariae are released from snails after the onset of darkness of an LD 12:12 hr photoperiod. Reversal of the photoperiod causes an almost immediate reversal of the emergence pattern. Cercariae encyst in the alderfly larva, Sialis infumata under natural conditions and in Culex pipiens larvae under ex- perimental conditions. Week-old metacercariae are experimentally infective to swordtails, Xiphophorus helleri, and immature specimens of P. hypentelii recovered agree with young worms taken from the natural fish host, Hypentelium nigricans. A seasonal change in the intensity of infection is noted for adult worms in H. nigricans.

Variations in the ultrastructure of the daughter sporocyst ofMicrophallus pygmaeus(Levinsen, 1881) (Digenea: Microphallidae) in chemically defined media

SummaryChanges in the ultrastructure of the daughter sporocyst and contained metacercariae ofMicrophallus pygmaeusduring culture in artificial seawater and modified Medium 199 were examined and compared with variations in oxygen consumption. The very early commencement and rapid progression of autolysis in the sporocyst body wall as compared with little or no change in most metacercariae in both media, together with the elevated oxygen consumption in the nutrient medium, suggests that most of the oxygen is consumed by the contained metacercariae. The almost simultaneous onset of body wall degeneration in both media suggests that the nutrient medium is not suitable for the maintenance of healthy daughter sporocysts.

The ultrastructure of the tegument of the daughter sporocyst of Microphallus similis (Jäg., 1900) (Digenea: Microphallidae)

SummaryIn the fully formed daughter sporocyst of Microphallus similis (Jäg.) the tegument is divided into a wide, outer cellular epithelium and a narrow, inner electron-dense anucleated microvillous syncytium. The narrow subtegument consists of circular and longitudinal muscle, nervous, synthesizing and germinal cells. It is suggested that during development of the tegument, an undifferentiated nucleated syncytium becomes divided by the formation of membranes between the nuclei and between the narrow, inner electron-dense microvillous and the outer cellular regions. The outer nucleated region of the tegument is homologous to the nucleated investing syncytium which surrounds redial and cercarial embryos and which is shed later in development. The retention of the nucleated region in some daughter sporocysts is, therefore, an example of paedogenesis.

The relationship between numbers of Schistosoma mansoni daughter sporocysts and miracidia.

The relationship between numbers of Schistosoma mansoni daughter sporocysts and miracidia.

The occurrence ofCercaria cerastodermae I Sannia, James, and Bowers, 1978 (Digenea: Monorchiidae) in populations ofCerastoderma edule (L.) from the commercial beds of the Lower Thames Estuary

A total of 10,406 cockles (Cerastoderma edule) were taken at monthly intervals between May 1975 and November 1976 from the Thames estuary, in order to demonstrate variations in percentage infection byCercaria cerastodermae I (Monorchiidae) with season, size, age, distribution and species of host. Cockles of different ages and sizes are equally susceptible to infection but season and perhaps species of host are important in determining the percentage infection. The maturity of the infection and the mean number of metacercariae per daughter sporocyst from the same host are also largely determined by season. The peak of both is reached in early spring. Parasitism decreases the host's shell growth rate and may increase the susceptibility to other digenean species.

Variations in the ultrastructure and oxygen consumption of the daughter sporocysts ofCercaria stunkardi Palombi, 1934 andCercaria linearis Stunkard, 1932 (Digenea: Opecoelidae) in chemically defined media

Variations in the oxygen consumption and alterations in the ultrastructure of the body wall in the daughter sporocysts ofCercaria stunkardi andCercaria linearis during maintainance in artificial sea water as compared with those in modified Medium 199, indicate that the latter is an unsatisfactory nutrient medium. Similar changes in oxygen consumption, which suggest endogenous carbohydrate and lipid utilization together with autolysis, occur in the nutrient and non-nutrient media. Autolysis in the body wall of the sporocysts progresses, nearly to complete destruction, with almost equal rapidity in both media. The contained cercariae, however, remain healthy and appear to consume most of the absorbed oxygen.

The ultrastructure of the daughter sporocyst ofCercaria littorinae saxatilis V Popiel, 1976 (Digenea: Microphallidae)

The body wall of the daughter sporocyst ofCercaria littorinae saxatilis V Popiel, 1976 consists of a syncytial tegument and a cellular subtegument. The tegument is a narrow layer with elongate microvilli over most of the surface but also present are widely separated bulbous regions containing nuclei. In the subtegument germinal and secretory cells lie below two layers of muscle.

Schistosoma haematobium in Bulinus guernei: Electron microscopy of hemocyte-sporocyst interactions

Electron microscopy has revealed that in Bulinus guernei (Gambian strain) snails infected with Schistosoma haematobium (Egyptian strain) daughter sporocysts and cercariae, two kinds of hemocytes called granulocytes and hyalinocytes are found associated with the sporocysts. Granulocytes are small, numerous, plumbophilic, and amoeboid. They contain lysosome-like granules. Hyalinocytes are large, sparse, less plumbophilic than granulocytes, and have intracellular microfilaments (about 9 nm wide), and few or no pseudopods. They are devoid of lysosome-like granules. Granulocytes and hyalinocytes infiltrate near sporocysts, but only granulocytes interact with sporocyst microvilli by contact. Granulocytes induce a restricted multilamellated encapsulation reaction. Extracellular microfilaments (about 12.5 nm wide), with a regular transverse structure pattern of about 50-nm periodicity, frequently are found along the outer surface of granulocytes located adjacent to sporocysts. Intracellular filamentous structures and a prominent glycocalyx also are features of the seemingly more active granulocytes contiguous with sporocysts. Cell adhesions may occur between surfaces of (1) granulocytes and sporocysts, (2) interdigitating pseudopodial processes of capsular granulocytes, and (3) granulocytes and hyalinocytes.

The Life History of Nezpercella lewisi Schell 1974 (Trematoda: Opecoelidae), a Parasite of the Northern Squawfish, and the Smallmouth Bass

Nezpercella lewisi is an intestinal parasite of Ptychocheilus oregonensis and Micropterus dolomieui in Idaho. The miracidium develops and hatches within 12 to 14 days at 22 to 26 C or within 50 to 60 days at 12 to 15 C. Cotylomicrocercous cercariae develop in daughter sporocysts in Lithoglyphys virens and encyst in fry of Richardsonius balteatus, Rhinichthys cataractae, R. osculus, Ptychocheilus oregonensis, Cottus rhotheus, and Salmo gairdneri. Natural infections with metacercariae were found in all of the above fishes except speckled dace and trout. Squawfish were fed fry of experimentally infected redside shiner and squawfish and partially developed specimens of N. lewisi recovered 8 weeks later. The larval stages are like those of trematodes in the family Ppecoelidae to which the species is transferred.

Accumulation of lipids in Schistosoma mansoni sporocysts cultured in vitro

Neutral lipids were detected histochemically in mother and daughter sporocysts of Schistosoma mansoni cultured in vitro. These lipids progressively increased with prolonged culture. There was little phospholipid and no fatty acid, esterases, or lipases found in sporocysts by the methods employed. Mother and daughter sporocysts incorporated labeled acetate from the culture medium but no further information was obtained on the complex lipid-synthesizing capabilities of these organisms.