The best known cases of cell autotomy are the formation of erythrocytes and thrombocytes(platelets) from progenitor cells that reside in special niches. Recently, autotomy of stem cells and its enigmatic interaction w...The best known cases of cell autotomy are the formation of erythrocytes and thrombocytes(platelets) from progenitor cells that reside in special niches. Recently, autotomy of stem cells and its enigmatic interaction with the niche has been reported from male germline stem cells(GSCs) in several insect species. First described in lepidopterans, the silkmoth, followed by the gipsy moth and consecutively in hemipterans, foremost the milkweed bug. In both, moths and the milkweed bug, GSCs form finger-like projections toward the niche, the apical cells(homologs of the hub cells in Drosophila). Whereas in the milkweed bug the projection terminals remain at the surface of the niche cells, in the gipsy moth they protrude deeply into the singular niche cell. In both cases, the projections undergo serial retrograde fragmentation with progressing signs of autophagy. In the gipsy moth, the autotomized vesicles are phagocytized and digested by the niche cell. In the milkweed bug the autotomized vesicles accumulate at the niche surface and disintegrate. Autotomy and sprouting of new projections appears to occur continuously. The significance of the GSC-niche interactions, however, remains enigmatic. Our concept on the signaling relationship between stem cell-niche in general and GSC and niche(hub cells and cyst stem cells) in particular has been greatly shaped by Drosophila melanogaster. In comparing the interactions of GSCs with their niche in Drosophila with those in species exhibiting GSC autotomy it is obvious that additional or alternative modes of stem cell-niche communication exist. Thus, essential signaling pathways, including niche-stem cell adhesion(E-cadherin) and the direction of asymmetrical GSC division- as they were found in Drosophila- can hardly be translated into the systems where GSC autotomywas reported. It is shown here that the serial autotomy of GSC projections shows remarkable similarities with Wallerian axonal destruction, developmental axon pruning and dying-back degeneration in neurodegenerative dise展开更多
Objective:To investigate the potential role of fresh Carica papaya(C.papaya)leaf extract on haematological and biochemical parameters and toxicological changes in a murine model.Methods:In total 36 mice were used for ...Objective:To investigate the potential role of fresh Carica papaya(C.papaya)leaf extract on haematological and biochemical parameters and toxicological changes in a murine model.Methods:In total 36 mice were used for the trial.Fresh C.papaya leaf extract[0.2 mL(2 g)/mouse]was given only to the test group(18 mice).General behavior,clinical signs and feeding patterns were recorded.Blood and tissue samples were collected at intervals.Haematological parameters including platelet,red blood cell(RBC),white blood cell<(WBC),packed cell volume(PCV),serum biochemistry including serum creatinine,serum glutamic-oxaloacetic transaminase(SCOT)and serum glutamic-pyruvic transaminase(SGPT)were determined.Organs for possible histopathological changes were examined.Results:Neither group exhibited alteration of behavior or reduction in food and water intake.Similarly,no significant changes in SCOT,SGPT and serum creatinine levels were delected in the test group.Histopathological organ changes were not observed in either group of mice except in three liver samples of the test group which had a mild focal necrosis.The platelet count(11.33±0.35)×10~5VμL(P=0.00004)and the RBC count(7.97±0.61)×10~/μL(P=0.00003)were significandy increased in the test group compared to that of the controls.However,WBC count and PCV(%)values were not changed significantly in the test group.The platelet count in the test group started to increase significantly from Day 3(3.4±0.18×10~5/μL),reaching almost a fourfold higher at Day 21(11.3×10~5/μL),while it was 3.8X10^5/μL and 5.5×10~5/μL at Day 3 and Day 21 respectively in the control.Likewise,the RBC count in the test group increased from 6×10~6/μL to 9×10~6/μL at Day 21 while it remained near constant in the control group(6×10~6μL).Conclusions:Fresh C.papaya leaf extract significandy increased the platelet and RBC counts in the test group as compared to controls.Therefore,it is very important to identify those chemicals of C.papaya leaves as it can be recommended to be used as a medicat展开更多
文摘The best known cases of cell autotomy are the formation of erythrocytes and thrombocytes(platelets) from progenitor cells that reside in special niches. Recently, autotomy of stem cells and its enigmatic interaction with the niche has been reported from male germline stem cells(GSCs) in several insect species. First described in lepidopterans, the silkmoth, followed by the gipsy moth and consecutively in hemipterans, foremost the milkweed bug. In both, moths and the milkweed bug, GSCs form finger-like projections toward the niche, the apical cells(homologs of the hub cells in Drosophila). Whereas in the milkweed bug the projection terminals remain at the surface of the niche cells, in the gipsy moth they protrude deeply into the singular niche cell. In both cases, the projections undergo serial retrograde fragmentation with progressing signs of autophagy. In the gipsy moth, the autotomized vesicles are phagocytized and digested by the niche cell. In the milkweed bug the autotomized vesicles accumulate at the niche surface and disintegrate. Autotomy and sprouting of new projections appears to occur continuously. The significance of the GSC-niche interactions, however, remains enigmatic. Our concept on the signaling relationship between stem cell-niche in general and GSC and niche(hub cells and cyst stem cells) in particular has been greatly shaped by Drosophila melanogaster. In comparing the interactions of GSCs with their niche in Drosophila with those in species exhibiting GSC autotomy it is obvious that additional or alternative modes of stem cell-niche communication exist. Thus, essential signaling pathways, including niche-stem cell adhesion(E-cadherin) and the direction of asymmetrical GSC division- as they were found in Drosophila- can hardly be translated into the systems where GSC autotomywas reported. It is shown here that the serial autotomy of GSC projections shows remarkable similarities with Wallerian axonal destruction, developmental axon pruning and dying-back degeneration in neurodegenerative dise
基金Supported by the National Research Council of Sri Lanka(Research Grant No.09-05)
文摘Objective:To investigate the potential role of fresh Carica papaya(C.papaya)leaf extract on haematological and biochemical parameters and toxicological changes in a murine model.Methods:In total 36 mice were used for the trial.Fresh C.papaya leaf extract[0.2 mL(2 g)/mouse]was given only to the test group(18 mice).General behavior,clinical signs and feeding patterns were recorded.Blood and tissue samples were collected at intervals.Haematological parameters including platelet,red blood cell(RBC),white blood cell<(WBC),packed cell volume(PCV),serum biochemistry including serum creatinine,serum glutamic-oxaloacetic transaminase(SCOT)and serum glutamic-pyruvic transaminase(SGPT)were determined.Organs for possible histopathological changes were examined.Results:Neither group exhibited alteration of behavior or reduction in food and water intake.Similarly,no significant changes in SCOT,SGPT and serum creatinine levels were delected in the test group.Histopathological organ changes were not observed in either group of mice except in three liver samples of the test group which had a mild focal necrosis.The platelet count(11.33±0.35)×10~5VμL(P=0.00004)and the RBC count(7.97±0.61)×10~/μL(P=0.00003)were significandy increased in the test group compared to that of the controls.However,WBC count and PCV(%)values were not changed significantly in the test group.The platelet count in the test group started to increase significantly from Day 3(3.4±0.18×10~5/μL),reaching almost a fourfold higher at Day 21(11.3×10~5/μL),while it was 3.8X10^5/μL and 5.5×10~5/μL at Day 3 and Day 21 respectively in the control.Likewise,the RBC count in the test group increased from 6×10~6/μL to 9×10~6/μL at Day 21 while it remained near constant in the control group(6×10~6μL).Conclusions:Fresh C.papaya leaf extract significandy increased the platelet and RBC counts in the test group as compared to controls.Therefore,it is very important to identify those chemicals of C.papaya leaves as it can be recommended to be used as a medicat
