Sarcoplasmic Reticulum of an Unusually Fast-acting Crustacean Muscle

The Sarcoplasmic Reticulum of a Fast-acting Fish Muscle

Ultrastructure and Calcium Transport in Crustacean Muscle Microsomes

Fragmented sarcoplasmic reticulum (FSR) from crustacean muscle was examined following preparation by a variety of electron microscopic techniques. The 30-40 A particles which appeared on the outer surface of FSR vesicles following negative staining were not observed following preparation by freeze-drying, freeze-etching, thin sectioning, or critical-point drying. Crustacean FSR exhibited high v...

Localization and Properties of the Cholinesterase in Crustacean Muscle

Cholinesterase (ChE) activity is present in crustacean muscle extracts. However, since acetylcholine (ACh) is not a neuromuscular transmitter in these animals, the role and exact localization of ChE was unknown. The histochemical localization of the enzyme was studied in whole muscle and in the sarcoplasmic reticulum fraction of the extract, 50-microm frozen sections of glutaraldehyde-fixed cra...

The Fine Structure of Fast and Slow Crustacean Muscles

Known phasic and tonic muscle fibers of the crab Cancer magister were studied by electron microscopy. Phasic fibers have sarcomeres about 4.5 micro long, small polygonal myofibrils, and a well-developed sarcoplasmic reticulum. The thick myofilaments, disposed in hexagonal array, are each surrounded by six thin filaments. The tonic fibers have a sarcomere length of about 12 micro, larger myofibr...

The Sarcoplasmic Reticulum of the Bat Cricothyroid Muscle

The bat cricothyroid muscle is believed to participate in the production of the short bursts of frequency modulated ultrasound which these animals use as an echolocation device. The evidence seems to indicate that this muscle must be extremely fast acting. It possesses a very well developed sarcoplasmic reticulum, consisting of intercommunicating longitudinal and transverse tubular elements. Th...