Biomaterial Database

Lectin cytochemistry and freeze-fracture study of phagocytosis in the rat retina. 1984

B J McLaughlin, and L G Boykins

Lectin cytochemistry and freeze-fracture intramembrane morphology have been studied in adult rat retinas during various stages of the phagocytic cycle. Animals were perfused with aldehydes at various times during the first 6 hours of light and the retinas were removed. Chopped sections of tissue were stained with one of two lectin-peroxidase conjugates: ricinis communis agglutinin (RCA), which is specific for n-acetylgalactosamine and galactose, or wheat germ agglutinin (WGA), which is specific for n-acetylglucosamine and sialic acid. Other sections were frozen and prepared for freeze fracture. During the first hour of light onset, numerous phagosomes are already present in the retinal pigment epithelial (RPE) cytoplasm. The engulfment stages of phagocytosis whereby the RPE microvilli wrap around and enclose shed rod outer segment (ROS) tips are rarely observed at this time. Newly formed phagosomes are present in the apical RPE cytoplasm while older and more osmiophilic phagosomes are located deeper within the RPE cytoplasm. Between 2 and 4 hours of light onset fewer phagosomes are present in the RPE cytoplasm, but it is common to observe many ROS tips in various stages of microvillous engulfment. By 6 hours phagosomes are rarely present but some engulfed ROS tips continue to be observed. Both RCA and WGA stain RPE microvilli and plasma membranes of photoreceptor outer segments. WGA, in addition, labels some intradisc membranes of intact and also shed outer segments that are being engulfed but does not label disc membranes in phagosomes. At all times, phagosomes are rimmed by both lectin stains, but their internal contents are never stained. Lysosomes and multivesicular and residual bodies are labeled by both lectins. Freeze-fractured retinas show that as the ROS tips are engulfed, particle-free areas are present on disc P-face (cytoplasmic) membranes. Many newly formed phagosomes also display particle-free membrane areas and older phagosome membranes are completely devoid of particles. These observations show that the changes in WGA staining and intramembrane particle distribution on disc membranes occur in retinas during phagocytosis and suggest that some membrane component that is present for the initial phagocytic interaction may be rapidly degraded thereafter.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D010587	Phagocytosis	The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).	Phagocytoses
D010947	Plants, Toxic	Plants or plant parts which are harmful to man or other animals.	Plants, Poisonous,Plant, Poisonous,Plant, Toxic,Poisonous Plant,Poisonous Plants,Toxic Plant,Toxic Plants
D011922	Rats, Mutant Strains	Rats bearing mutant genes which are phenotypically expressed in the animals.	Mutant Strains Rat,Mutant Strains Rats,Rat, Mutant Strains,Strains Rat, Mutant,Strains Rats, Mutant
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
D002367	Ricinus communis	A species in the family EUPHORBIACEAE that is the source of CASTOR OIL.	Castor Bean,Castor Bean Plant,Castor Oil Plant,Ricinus sanguineus,Bean, Castor,Beans, Castor,Castor Bean Plants,Castor Beans,Castor Oil Plants,Plant, Castor Bean,Plant, Castor Oil,Plants, Castor Bean,Plants, Castor Oil
D005614	Freeze Fracturing	Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.	Fracturing, Freeze,Fracturings, Freeze,Freeze Fracturings
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014909	Wheat Germ Agglutinins	Lectins purified from the germinating seeds of common wheat (Triticum vulgare); these bind to certain carbohydrate moieties on cell surface glycoproteins and are used to identify certain cell populations and inhibit or promote some immunological or physiological activities. There are at least two isoforms of this lectin.	Agglutinins, Wheat Germ,Lectins, Triticum Vulgare,Lectins, Wheat Germ,Triticum Vulgare Lectin,Triticum Vulgare Lectins,Wheat Germ Agglutinin,Wheat Germ Lectin,Wheat Germ Lectins,Wheat Germ Agglutinin Isolectin 1,Wheat Germ Agglutinin Isolectin 2,Agglutinin, Wheat Germ,Germ Agglutinin, Wheat,Germ Lectin, Wheat,Lectin, Triticum Vulgare,Lectin, Wheat Germ,Vulgare Lectin, Triticum
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus