Osteoclastogenesis and lymph node organogenesis in different species of Egyptian rats

The development of lymphoid organs depends on the correct expression of several molecules within a defined timeframe during ontogeny. Although this is an extremely complex process, with each secondary lymphoid tissue requiring subtly different signals, a common framework for lymphoid development is beginning to emerge. Bone remodeling is tightly regulated by a molecular trial composed of OPG/RANK/RANKL. The receptor activator of RANKL [localized on osteoblasts] enhances osteoclastogenesis via interaction with its receptor RANK [localized on osteoclasts], whereas osteoprotegerin [OPG] [produced by osteoblasts] inhibits this osteoclastogenesis by binding to RANKL. The RANK provides critical signals necessary for lymph node organogenesis and osteoclast differentiation. The TNF family molecule OPGL has been identified as a potential osteoclast differentiation factor and regulator of interactions between T cells and dendritic cells in vitro. Thus OPGL is a new regulator of lymph node organogenesis and lymphocyte development and is an essential osteoclast differentiation factor in vivo: So, the result of this study showed that lymph node organogenesis appears to require adequate quantity of RANKL, and this significant level can apparently persist despite marked overexpression of the soluble RANKL inhibitor OPG

Antiviral immunity in the red swamp crayfish, Procambarus Clarkii: hemocyte production, proliferation and apoptosis

In the present study, the pathogenic mechanism of white spot syndrome [WSSV] in crayfish, Procambarus clarkii by investigating activities of immune cells related to innate immune function during infection was explored. White spot disease caused by WSSV leads to devastating losses in crayfish farming. Examination by transmission electron microscopy revealed abundant WSSV particles and significant changes in the different lymphoid organs of infected crayfish. WSSV infection caused parts of the gill epithelium and microvilli to be reduced in number and size or damaged, meanwhile, the mitochondria, morphology changed, with parts of the cristae diminished leaving large vacuoles. Moreover, electron dense deposits appeared and hetero-chromatinized nuclei could be seen in blood cells with ruptured nuclear membranes and outflow of nucleoplasm. Also, evident were very densely basophilic inclusions were found in interstitial hepato-pancreatic tissue, connective tissue underlying the mid gut, cardiac tissue, gill tissue and hematopoietic tissue. Transmission electron microscopy revealed the presence of previously undescribed rod-shaped, enveloped versions in the cytoplasm adjacent to the nuclei of cells from various tissues

Immunological and molecular detection of digenetic infections in different species of Egyptian freshwater snails

Due to the possibility of utilizing different snails in the combat of Schistosoma in Egypt; it is important to study the role it may play in transmitting other trematodes of medical and veterinary importance. Taking this background into consideration, polymerase chain reaction [PCR] assay was designed to identify trematode species at larval stages in intermediate hosts [cercariae in snails] using a combination of standard and molecular methods. This PCR assay was also applied to naturally infected molluscan in order to assess the use of the procedure for detection. The importance of the present study was to demonstrate the epidemiological situation and application in control

Ichthyophthirius multifiliis infection induces apoptosis in different species of tilapia

The parasitic ciliate Ichthyophthirius multifiliis [Ich] is one of the most important protozoan pathogens of freshwater fish worldwide. Examination of 4 species of Tilapia from the River Nile recorded highest rate infection in Oreochromis niloticus, followed by Oreochromis aureus, Sarotherodon galilaeus and Tilapia zilli. By electron microscopy, apoptotic cells collected from Tilapia species infected with "Ich" showed an aggregation on the apical and basal parts of the ciliated and non-ciliated endothelial lining the gill epithelium. Ultrastructural analysis showed that the chromatin in the liver of Ich-infected O. niloticus was highly condensed and massed at the center of the nucleus. UItrastructural analysis of "Ich" infected O. aureus showed that the nuclear membrane of hepatocytes was also shrunken. In S. galilaeus, chromatin was highly condensed, fragmented and massed at the nuclear center, occasionally forming crescent-shaped masses. Ultrastructural of O. niloticus spleen showed that the macrophage number was comparatively high as compared to control. In O. aureus, damaged splenic cell number did not change, and phagocytic capacity of macrophages was not very high. In Ich-infected S. galilaeus, a marked decrease in splenic cells number was seen. Analysis of DNA by agarose gel electrophoresis on gill, liver and spleen cells showed a ladder of DNA fragments in multiple of 180bp in length, pointing to an internucleosomal DNA cleavage