Correlative and Dynamic Imaging of the Hatching Biology of Schistosoma japonicum from Eggs Prepared by High Pressure Freezing (original) (raw)
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The proteome of the insoluble Schistosoma mansoni eggshell skeleton
International Journal for Parasitology, 2011
In schistosomiasis, the majority of symptoms of the disease is caused by the eggs that are trapped in the liver. These eggs elicit an immune reaction that leads to the formation of granulomas. The eggshell, which is a rigid insoluble structure built from cross-linked proteins, is the site of direct interaction between the egg and the immune system. However, the exact protein composition of the insoluble eggshell was previously unknown. To identify the proteins of the eggshell of Schistosoma mansoni we performed LC-MS/ MS analysis, immunostaining and amino acid analysis on eggshell fragments. For this, eggshell protein skeleton was prepared by thoroughly cleaning eggshells in a four-step stripping procedure of increasing strength including urea and SDS to remove all material that is not covalently linked to the eggshell itself, but is part of the inside of the egg, such as Reynold's layer, von Lichtenberg's envelope and the miracidium. We identified 45 proteins of which the majority are non-structural proteins and non-specific for eggs, but are house-keeping proteins that are present in large quantities in worms and miracidia. Some of these proteins are known to be immunogenic, such as HSP70, GST and enolase. In addition, a number of schistosome-specific proteins with unknown function and no homology to any known annotated protein were found to be incorporated in the eggshell. Schistosome-specific glycoconjugates were also shown to be present on the eggshell protein skeleton. This study also confirmed that the putative eggshell protein p14 contributes largely to the eggshell. Together, these results give new insights into eggshell composition as well as eggshell formation. Those proteins that are present at the site and time of eggshell formation are incorporated in the cross-linked eggshell and this cross-linking does no longer occur when the miracidium starts secreting proteins.
Some Observations on the Egg - Hatching Processes in Schistosoma Mansoni
A study was made in the laboratory to determine the processes involved in the hatching of Schistosoma mansoni eggs. Of the 296 viable eggs examined under a special compound microscope, anterior and posterior orientations of the miracidium within eggs occurred in almost equal proportions. Three main types of egg-shell ruptures (oblique, vertical and horizontal) were recorded. Some 8 distinct stages in the egg-hatching processes were identified. These stages include: the establishment of osmotic gradient positively towards the egg interior and the formation of contractile vacuoles (CV); the erratic movement of the cilia and the enlargement of CV in response to the exertion of osmotic pressure (due to influx of water) on the miracidium; increased ciliary beating and bi-polar alignment of CV; the rolling up and the centrifugal movement of the miracidium; the rupturing of egg shell with a distinct hatching pattern and the withdrawal process leading to the final emergence of actively swim...
Schistosoma mansoni: The egg, biosynthesis of the shell and interaction with the host
Experimental Parasitology, 2012
The schistosome eggshell is a hardened and tanned structure made from cross-linked proteins. It is synthesized within the female worm from many different kinds of proteins and glycoproteins. Once the egg is released in the circulation, the outer surface of the eggshell is exposed and hence a direct site of interaction between the parasite and the host. The major eggshell protein is p14, but about one third of the eggshell is made from common cellular proteins, some of which are known to be immunogenic. This has many consequences for parasite-host interactions. However, so far, the eggshell has gained little attention from researchers. We will discuss the structure of the eggshell and its role in granuloma formation, host factor binding and egg excretion.
Identification of schistosomal eggs
Journal of Immunological Methods, 1986
A number of parasitic worms produce large numbers of eggs which may be identified by microscopy in the excretions of the host. Alternative identification methods would be useful for epidemiological purposes and this paper describes a non-microscopical method for the demonstration of schistosomal eggs, which is based on the release of soluble material from eggs during hatching in water. Substances present in hatch fluid from Schistosoma mansoni eggs were adsorbed to nitrocellulose paper and then visualized as small stained spots using horseradish peroxidase (HRP)-labeled lectins or specific antibodies. In this way the number of living eggs present in the sample could be estimated. The method may be useful as a basis for the development of diagnostic assays.
The embryonic development of Schistosoma mansoni eggs: proposal for a new staging system
Development Genes and Evolution, 2009
Schistosomiasis is a water-borne parasitic illness caused by neoophoran trematodes of the genus Schistosoma. Using classical histological techniques and whole-mount preparations, the present work describes the embryonic development of Schistosoma mansoni eggs in the murine host and compares it with eggs maintained under in vitro conditions. Two pre-embryonic stages occur inside the female worm: the prezygotic stage is characterized by the release of mature oocytes from the female ovary until its fertilization. The zygotic stage encompasses the migration of the zygote through the ootype, where the eggshell is formed, to the uterus. Fully formed eggs are laid still undeveloped, without having suffered any cleavage. In the outside environment, eight embryonic stages can be defined: stage 1 refers to early cleavages and the beginning of yolk fusion. Stage 2 represents late cleavage, with the formation of a stereoblastula and the onset of outer envelope differentiation. Stage 3 is defined by the elongation of the embryonic primordium and the onset of inner envelope formation. At stage 4, the first organ primordia arise. During stages 5 to 7, tissue and organ differentiation occurs (neural mass, epidermis, terebratorium, musculature, and miracidial glands). Stage 7 is characterized by the nuclear condensation of neurons of the central neural mass. Stage 8 refers to the fully formed larva, presenting muscular contraction, cilia, and flame-cell beating. This staging system was compared to a previous classification and could underlie further studies on egg histoproteomics (morphological localizome). The differentiation of embryonic structures and their probable roles in granulomatogenesis are discussed herein.
Cracks in the shell—zooming in on eggshell formation in the human parasite Schistosoma mansoni
Development Genes and Evolution, 2005
Schistosomiasis, currently the second most common parasitic disease of humans in tropical regions is caused by the eggs of trematode worms of the genus Schistosoma. Understanding egg formation and specifically the synthesis of the eggshell comprises, consequently, a promising starting point to cure and prevent the disease. To shed light on the genetics of the latter process, we analysed the three known S. mansoni eggshell proteins P14, P19 and P48 against the background of the species' inferred proteome and of eggshell proteins identified in other trematode species. Our results suggest that eggshell formation in Schistosoma involves a multitude of different proteins organised in currently three distinct protein families (P14, P48 and P34 eggshell protein family). The first two families are of simple structure. Their respective members share a substantial degree of sequence similarity and are, to date, observed only in the genus Schistosoma. In contrast, the P34 family of eggshell proteins is complex. Its in part highly diverged members share only a conserved motif of 67-aa length on average and are detected in various trematode species. The resulting widespread occurrence of this protein motif suggests an important role during eggshell formation in trem-atodes. Screening more than 7,000 putative proteins of S. mansoni, we could identify six new members of the P34 protein family that are likely to be involved in eggshell formation in this species.
J Immunol Method, 1986
A number of parasitic worms produce large numbers of eggs which may be identified by microscopy in the excretions of the host. Alternative identification methods would be useful for epidemiological purposes and this paper describes a non-microscopical method for the demonstration of schistosomal eggs, which is based on the release of soluble material from eggs during hatching in water. Substances present in hatch fluid from Schistosoma mansoni eggs were adsorbed to nitrocellulose paper and then visualized as small stained spots using horseradish peroxidase (HRP)-labeled lectins or specific antibodies. In this way the number of living eggs present in the sample could be estimated. The method may be useful as a basis for the development of diagnostic assays.
Proteomic analysis of Schistosoma mansoni egg secretions
Molecular and Biochemical Parasitology, 2007
Schistosomiasis remains a largely neglected, global health problem. The morbid pathology of the disease stems from the host's inflammatory response to parasite eggs trapped in host tissues. Long term host/parasite survival is dependent upon the successful modulation of the acute pathological response, which is induced by egg antigens. In this study, using Multidimensional Protein Identification Technology, we identified the Schistosoma mansoni egg secretome consisting of 188 proteins. Notably we identified proteins involved in redox balance, molecular chaperoning and protein folding, development and signaling, scavenging and metabolic pathways, immune response modulation, and 32 novel, previously uncharacterized schistosome proteins. We localized a subset of previously-characterized schistosome proteins identified in egg secretions in this study, to the surface of live S. mansoni eggs using the circumoval precipitin reaction. The identification of proteins actively secreted by live schistosome eggs provides important new information for understanding immune modulation and the pathology of schistosomiasis. Protein Accession Seq ct % Cov Spec ct Relative Abundance SecP Phosphoglycerate mutase Q8WT66 6