Diurnal changes of lysosomes including ultrastructural changes of phagosomes and acid phosphatase reactions in phagosomes, as well as diurnal biochemical changes in cathepsin D activity, were studied in the retinal pigment epithelium (RPE) of the rabbit. The rabbit was maintained on a natural light-dark cycle over seven days in fall and was sacrificed at various times during the day and night. The number of lysosomes or phagosomes in the RPE was the highest at 1.5 hours after exposure to sunlight (8:00 AM), and thereafter decreased with time. Three types of phagosomes were observed and acid phosphatase reactions were different in each type of phagosome; the fresh phagosomes were negative or positive, lamellar bodies positive, and dense bodies partially positive. The biochemical activity of cathepsin D was the highest at 8:00 AM, and this was consistent with the time of peak in phagocytic activity in the RPE. This report shows that phagocytic activity in the RPE occurred in the early stage after exposure to sunlight, and that fresh phagosomes were sequentially degraded to lamellar or dense bodies. Cathepsin D activity also increased, and this was consistent with the phagocytic activity in the RPE.
Acid Phosphatase/metabolism ; Animals ; Cathepsin D/metabolism ; Cell Count ; Choroid/metabolism/ultrastructure ; Circadian Rhythm/*physiology ; Lysosomes/*metabolism/ultrastructure ; Phagosomes/*metabolism/ultrastructure ; Pigment Epithelium of Eye/*metabolism/ultrastructure ; Rabbits

The article reviewed the advance and the forensic meaning of macrophage on the wound age estimation during the wound healing process in resent years. It has also been summarized the relationship between macrophages and wound age estimation on the expression of cytokines derived from macrophages, the changes of macrophage phenotypes and the development process of phagosomes in macrophages after wounding. It is suggested that some regular and characteristic changes of macrophage should be a useful mark to wound age estimation and reminds therefore further study in this field.
Forensic Medicine ; Humans ; Interleukin-1/genetics* ; Interleukin-10/genetics* ; Interleukin-6/genetics* ; Macrophages/physiology* ; Phagosomes/physiology* ; Phenotype ; Time Factors ; Transforming Growth Factor beta/genetics* ; Tumor Necrosis Factor-alpha/genetics* ; Wound Healing/physiology*

Autophagy-related protein 8 (Atg8) is an essential component of autophagy formation and encystment of cyst-forming parasites, and some protozoa, such as, Acanthamoeba, Entamoeba, and Dictyostelium, have been reported to possess a type of Atg8. In this study, an isoform of Atg8 was identified and characterized in Acanthamoeba castellanii (AcAtg8b). AcAtg8b protein was found to encode 132 amino acids and to be longer than AcAtg8 protein, which encoded 117 amino acids. Real-time PCR analysis showed high expression levels of AcAtg8b and AcAtg8 during encystation. Fluorescence microscopy demonstrated that AcAtg8b is involved in the formation of the autophagosomal membrane. Chemically synthesized siRNA against AcAtg8b reduced the encystation efficiency of Acanthamoeba, confirming that AcAtg8b, like AcAtg8, is an essential component of cyst formation in Acanthamoeba. Our findings suggest that Acanthamoeba has doubled the number of Atg8 gene copies to ensure the successful encystation for survival when 1 copy is lost. These 2 types of Atg8 identified in Acanthamoeba provide important information regarding autophagy formation, encystation mechanism, and survival of primitive, cyst-forming protozoan parasites.
Acanthamoeba castellanii/cytology/*genetics/physiology ; Amebiasis/*parasitology ; Amino Acid Sequence ; Autophagy ; Cell Membrane/metabolism ; DNA, Protozoan/chemistry/genetics ; Gene Dosage ; Gene Silencing ; Genes, Reporter ; Humans ; Molecular Sequence Data ; Phagosomes/metabolism ; Protein Isoforms ; Protozoan Proteins/*genetics/metabolism ; RNA, Messenger/genetics ; RNA, Protozoan/genetics ; RNA, Small Interfering/chemical synthesis/genetics ; Recombinant Fusion Proteins ; Sequence Alignment