Observations additional to those previously reported (34) on boutons terminaux and club endings Mauthner cell lateral dendrites, primarily as seen in sections of permanganate-fixed material, are described. Certain new findings OSO(4)-fixed also included. The closely packed the synaptic bed with approximately 100 150 A gaps between their contiguous unit membranes a few interspersed glial extensions. Their membrane complexes (SMC) appear pairs separated by 150A clefts. They contain many...

An electron microscope study of goldfish Mauthner cells is reported.(1) The cell covered by a synaptic bed approximately 5 micro thick containing unusual amounts extracellular matrix material in which synapses and clear glia processes are implanted. preterminal neurites closely invested an interwoven layer filament-containing satellite processes. axoplasm the club endings contains oriented mitochondria, neurofilaments, neurotubules, relatively few vesicles. That boutons terminaux many...

In sections of KMnO(4)-fixed, developing mouse sciatic nerves, the central gap mesaxons in myelinating fibers is normally closed with close apposition outside approximately 20 A dense strata two 75 Schwann cell membranes. The combined make intraperiod line bisecting each myelin lamella. 150 mesaxon elaborated spirally around axon either a right hand or left spiral, and its inside (cytoplasmic) form major lines myelin. hypotonic solutions lamellae adult frog myelinated split apart along...

Myoneural junctions in Anolis are characterized by the formation of troughs surface muscle fibers which small branches terminal axon lie. The membrane lining is thrown into complex branching and anastomosing folds, compose subneural apparatus Couteaux. A compound 500 to 700 thick separates axoplasm from sarcoplasm at endings. This consists five distinct layers described detail. thin layer cytoplasm (probably Schwann) extracellular space surfaces junctional troughs. Terminal lacks axoplasmic...

ABSTRACT Analyses have been made of the ionic composition body fluids some twenty marine invertebrates belonging to five phyla. The were again analysed after dialysis in collodion sacs against samples original sea water which animals had kept. Comparison two analyses terms weight gives a true measure regulation by taking into account such factors as Donnan equilibrium and formation calcium-protein complexes those with significant concentrations protein their blood. Some is found all...

Abstract Producing monodisperse nanoparticles is essential to ensure consistency in biological experiments and enable a smooth translation into the clinic. Purification of samples discrete sizes shapes may not only improve sample quality, but also provide us with tools understand which physical properties are beneficial for drug delivery vector. In this study, using polymersomes as model system, we explore four techniques purifying pre-formed fractions based on their size, shape or density....

ABSTRACT The blood or coelomic fluid has been analysed in sixteen marine invertebrates to determine the amount of ionic regulation. Little regulation is shown by Holothuria and bivalves Ostrea Mytilus except potassium. accumulate potassium (up 135% concentration sea water), galloprovincialis accumulates sulphate (to 120%), an unusual feature. nudibranch Archidoris (128%), calcium (132%) magnesium (107%), while sipunculid Phascolosoma lower (69%) (91 %) but higher sodium (104%). cephalopod...

Adult chameleon myelinated peripheral nerve fibers have been studied with the electron microscope in thin sections. The outer lamella of myelin sheath has found to be connected as a double membrane surface Schwann cell. inner is similar axon-Schwann membrane. relations these connecting membranes suggest that layered structure composed which closely wound about axon helix. These findings support new theory myelinogenesis proposed recently by Geren. possible significance results respect cell...

Junctions between fiber cells of bovine lenses have been isolated in milligram quantities, without using detergents or proteases. The structure the junctions has studied by thin-section, negative-stain, and freeze-fracture electron microscopy x-ray diffraction. are large most often an undulating surface topology as determined thin sectioning freeze-fracture. These undulations resemble tongue-and-groove interdigitations lens previously seen others (D. H. Dickson G. W. Crock, 1972, Invest....

An electron microscope study has been made of octopus and amphibian photoreceptors, after fixing with KMnO4 embedding in araldite. What previously seen as a single dense stratum bounding the tubular compartments (octopus) or double membrane discs (rods cones), now shows structure. We interpret this showing that these tubules have similar surfaces, which are probably directly related to cell membrane. This is confirmed by finding (at least occasionally) continuous

Schmidt-Lanterman clefts in frog sciatic nerves have been studied thin sections by electron microscopy utilizing permanganate fixation and araldite embedding. It is shown that they are shearing defects myelin which the lamellae separated widely at major dense lines. Each lamella consisting of two apposed Schwann cell unit membranes approximately 75 A across traverses cleft intact. The composing each sometimes slightly ( 50 to 100 A) clefts. layers between contain membranous structures may be...

In this report I review the origins of unit membrane theory in detail, including certain relevant descriptions peripheral nerve structure. Discussion chemical composition membranes particularly emphasizes myelin and frog retinal rod outer segments. Additional discussion focuses on recent biophysical studies segments leading to accurate high resolution electron density plots, general problem lipid protein interactions model systems membranes, finally, special macromolecular arrays membranes....

ABSTRACT Included in the Chordata are groups of widely different organization which have certain common morphological features at some stage their existence, a notochord, hollow dorsal nerve-cord, and gill-pouches or gill-clefts. The various subphyla differ most other characters, physiology, especially methods respiration, feeding, digestion, excretion, reproduction, locomotion. A study composition blood members aquatic shows that variations exist equilibrium between internal external media...

Summary1. Electron microscope studies of a type physiologically polarized synapse in the crayfish and squid have shown that consists region characterized by processes postsynaptic axoplasm lying presynaptic Schwann cell cytoplasm. 2. The axolemmal membrane fiber completely envelops synaptic is closely applied to corresponding manner such single double thickness sometimes produced. 3. Pre- membranes are structurally similar about 300 Â thickness. 4. contains distinctly increased number...

Optimizing the shape of a nanovector influences its interaction with cell and determines internalization kinetics. Block copolymer amphiphiles self-assemble into monodisperse structures in aqueous solutions have been explored extensively as drug delivery vectors. However, structure self-assembled block copolymers has mainly limited to spherical vesicles or worm-like micelles. Here we show controlled formation purification tubular polymersomes, long cylindrical vesicles. Tubular polymersomes...

ABSTRACT In the Lumbricidae secretion of calciferous glands consists mainly calcium carbonate, percentage carbonate in calcite concretions being 95−97 per cent. Feeding experiments indicate that can be derived from common inorganic salts such as sulphate, phosphate, oxalate, chloride, and nitrate, also pear leaves. Measurements hydrogen-ion concentration gut, soil, castings specimens Lumbricus terrestris show tendency cast to more neutral than soil is due secretions gut a whole, not glands....

One of the features Arthropoda is possession a stiff outer covering chitin secreted by epidermis. This cast periodically, and it characteristic group that increase in size takes place immediately after ecdysis or moulting old skin. During this period new skin soft extensible. In many higher Crustacea, chitinous hardened deposition calcium salts, chiefly carbonate phosphate, thus forming protective exoskeleton. Under term are included endophragmal skeleton partially calcified foregut.