scholarly journals DIFFERENTIATION OF MONOCYTES

1971 ◽  
Vol 50 (2) ◽  
pp. 498-515 ◽  
Author(s):  
Barbara A. Nichols ◽  
Dorothy Ford Bainton ◽  
Marilyn G. Farquhar

The origin, content, and fate of azurophil granules of blood monocytes were investigated in several species (rabbit, guinea pig, human) by electron microscopy and cytochemistry. The life cycle of monocytes consists of maturation in bone marrow, transit in blood, and migration into tissues where they function as macrophages. Cells were examined from all three phases. It was found that: azurophil granules originate in the Golgi complex of the developing monocyte of bone marrow and blood, and ultimately fuse with phagosomes during phagocytosis upon arrival of monocytes in the tissues. They contain lysosomal enzymes in all species studied and peroxidase in the guinea pig and human. These enzymes are produced by the same pathway as other secretory products (i.e., they are segregated in the rough ER and packaged into granules in the Golgi complex). The findings demonstrate that the azurophil granules of monocytes are primary lysosomes or storage granules comparable to the azurophils of polymorphonuclear leukocytes and the specific granules of eosinophils. Macrophages from peritoneal exudates (72–96 hr after endotoxin injection) contain large quantities of lysosomal enzymes throughout the secretory apparatus (rough ER and Golgi complex), in digestive vacuoles, and in numerous coated vesicles; however, they lack forming or mature azurophil granules. Hence it appears that the monocyte produces two types of primary lysosomes during different phases of its life cycle—azurophil granules made by developing monocytes in bone marrow or blood, and coated vesicles made by macrophages in tissues and body cavities.

1967 ◽  
Vol 34 (2) ◽  
pp. 577-596 ◽  
Author(s):  
James D. Jamieson ◽  
George E. Palade

It has been established by electron microscopic radioautography of guinea pig pancreatic exocrine cells (Caro and Palade, 1964) that secretory proteins are transported from the elements of the rough-surfaced endoplasmic reticulum (ER) to condensing vacuoles of the Golgi complex possibly via small vesicles located in the periphery of the complex. To define more clearly the role of these vesicles in the intracellular transport of secretory proteins, we have investigated the secretory cycle of the guinea pig pancreas by cell fractionation procedures applied to pancreatic slices incubated in vitro. Such slices remain viable for 3 hr and incur minimal structural damage in this time. Their secretory proteins can be labeled with radioactive amino acids in short, well defined pulses which, followed by cell fractionation, makes possible a kinetic analysis of transport. To determine the kinetics of transport, we pulse-labeled sets of slices for 3 min with leucine-14C and incubated them for further +7, +17, and +57 min in chase medium. At each time, smooth microsomes ( = peripheral elements of the Golgi complex) and rough microsomes ( = elements of the rough ER) were isolated from the slices by density gradient centrifugation of the total microsomal fraction. Labeled proteins appeared initially (end of pulse) in the rough microsomes and were subsequently transferred during incubation in chase medium to the smooth microsomes, reaching a maximal concentration in this fraction after +7 min chase incubation. Later, labeled proteins left the smooth microsomes to appear in the zymogen granule fraction. These data provide direct evidence that secretory proteins are transported from the cisternae of the rough ER to condensing vacuoles via the small vesicles of the Golgi complex.


Author(s):  
Corazon D. Bucana

In the circulating blood of man and guinea pigs, glycogen occurs primarily in polymorphonuclear neutrophils and platelets. The amount of glycogen in neutrophils increases with time after the cells leave the bone marrow, and the distribution of glycogen in neutrophils changes from an apparently random distribution to large clumps when these cells move out of the circulation to the site of inflammation in the peritoneal cavity. The objective of this study was to further investigate changes in glycogen content and distribution in neutrophils. I chose an intradermal site because it allows study of neutrophils at various stages of extravasation.Initially, osmium ferrocyanide and osmium ferricyanide were used to fix glycogen in the neutrophils for ultrastructural studies. My findings confirmed previous reports that showed that glycogen is well preserved by both these fixatives and that osmium ferricyanide protects glycogen from solubilization by uranyl acetate.I found that osmium ferrocyanide similarly protected glycogen. My studies showed, however, that the electron density of mitochondria and other cytoplasmic organelles was lower in samples fixed with osmium ferrocyanide than in samples fixed with osmium ferricyanide.


Author(s):  
Marieke Goedhart ◽  
Stephanie Gessel ◽  
Robbert van der Voort ◽  
Edith Slot ◽  
Beth Lucas ◽  
...  

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