Retinopetal neurons and fibers in the lamprey

The structure of the retinopetal system was studied in the lamprey (Lampetra fluviatilis) using the horseradish peroxydase technique of axonal transport. Anterograde axonal transport within the retinofugal fibers had first been cut off by chemical destruction of the retina or severing the optic nerve, thereby enabling observation of retinopetal fibers unmasked by labeled visual afferents. Central neurons of the retinopetal systems could thus be distinguished bilaterally in the periventricular tegmental area of the midbrain and the mesencephalic reticular zone. Retinopetal fibers were traced in the structure of the axial optic tract.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Laboratory of Sensory Psychophysiology, Paris University VI, Paris, France. Translated from Neirofiziologiya, Vol. 17, No. 6, pp. 723–727, November–December, 1985.     

Subcellular localization of dystrophin and vinculin in cardiac muscle fibers and fibers of the conduction system of the chicken ventricle

The subcellular localization of dystrophin and vinculin was investigated in cardiac muscle fibers and fibers of the conduction system of the chicken ventricle by immunofluorescence confocal microscopy. In ventricular cardiac muscle fibers, strong staining with antibody against dystrophin appeared as regularly arranged transverse striations at the sarcolemmal surface, and faint but uniform staining was seen in narrow strips between these striations. In fibers of the ventricular conduction system, the sarcolemma was stained uniformly with this antibody, but strong staining was found as regular striations in many areas and as scattered patches in other areas of the sarcolemma. These intensely stained striations and scattered patches of dystrophin were colocalized with those of vinculin. Because dystrophin striations were located at the level of Z bands of the underlying myofibrils, they were regarded as the concentration of this protein at costameres together with vinculin. In fibers of the conduction system, myofibrils were close to the sarcolemma where dystrophin and vinculin assumed a striated pattern, at some distance from the cell membrane where these proteins exhibited a patchy distribution, and distant from the sarcolemma where dystrophin was uniformly distributed. These data suggest that the distribution patterns of dystrophin reflect the degree of association between the sarcolemma and underlying myofibrils.     

Efferent fibers innervate gustatory and mechanosensitive afferent fibers in frog fungiform papillae

A possibility of efferent innervation of gustatory and mechanosensitive afferent fiber endings was studied in frog fungiform papillae with a suction electrode. The amplitude of antidromic impulses in a papillary afferent fiber induced by antidromically stimulating an afferent fiber of glossopharyngeal nerve (GPN) with low voltage pulses was inhibited for 40 s after the parasympathetic efferent fibers of GPN were stimulated orthodromically with high voltage pulses at 30 Hz for 10 s. This implies that electrical positivity of the outer surface of papillary afferent membrane was reduced by the efferent fiber-induced excitatory postsynaptic potential. The inhibition of afferent responses in the papillae was blocked by substance P receptor blocker, L-703,606, indicating that substance P is probably released from the efferent fiber terminals. Slow negative synaptic potential, which corresponded to a slow depolarizing synaptic potential, was extracellularly induced in papillary afferent terminals for 45 s by stimulating the parasympathetic efferent fibers of GPN with high voltage pulses at 30 Hz for 10 s. This synaptic potential was also blocked by L-703,606. These data indicate that papillary afferent fiber endings are innervated by parasympathetic efferent fibers.     

Biologically active fibers based on chitosan-coated lyocell fibers

The possibilities of obtaining biologically active cellulose–chitosan fibers were examined. An effective two-stage method was developed. The first stage involves the formation of dialdehyde cellulose by the potassium periodate oxidation of lyocell fibers, which is able to form Schiff’s base with chitosan. In the second stage, chitosan-coated lyocell fibers were prepared by subsequent treatment of oxidized lyocell fibers with a solution of chitosan in aqueous acetic acid. The impact of this two-stage protocol on the chemical and physical properties of lyocell fibers was evaluated by determining carbonyl group content, fineness and tensile strength of fibers, as well as chitosan content in the composite cellulose–chitosan fibers. Antibacterial activity of the chitosan-coated lyocell fibers against different pathogenens: Staphylococcus aureus and Escherichia coli, was confirmed in vitro experiments.     

Papermaking fibers

True paper, in the technical sense of the term, was first made in China in 105a.d. from the bast fibers of paper mulberry and probably also from bamboo. For many centuries old rags, principally cotton or linen, supplied the papermakers with raw material In modern times, sprucewood fibers have long been outstanding for papermaking. In recent decades, however, the spruces have been equalled, if not surpassed, in tonnage used, by various species of pine, especially the southern yellow pines. Of secondary importance have been the fibers of dozens of other species.     

Retraction fibers and leucocyte chemotaxis

Calculation of the attractant concentrations during leucocyte chemotaxis allows the possibility of a multiple-receptor model in which receptors on retraction fibers and the cell body can detect gradients by the absolute differences in concentration between receptors.     

Cell walls and synthetic fibers

Many theoretical chemists now discount much chemical and botanical work in cell wall research before 1920 and all current work which indicates the presence and importance of non-cellulosic materials in determining cell-wall properties.     

The effect of pyrophosphate on the rigor fibers of rabbit m. psoas fibers

The effect of MgPPi on the rigor force of glycerinated fibres in the range of ionic strength 75-250 mM at two temperatures 18 degrees and 5 degrees C was studied. At 18 degrees C the maximum of this effect was above the range of average ionic strength. At 5 degrees C the greatest effect of MgPPi was observed at low ionic strength.     

Plant fibers in the paper industry

For 20 centuries, vegetable fibers from various sources have been converted into thin sheets for use in trade, communications, law, and even for shelter. Cotton and linen rags were the first fibrous raw materials to acquire widespread status in paper making, and they are still needed for specialty products. Increasing demands for paper ultimately surpassed the availability of rags, so that other sources of fiber were sought. About the year 1800, numerous other materials of agricultural origin began to come into use somewhat temporarily. Although woods have become the prime source of paper making fibers during the last 100-125 years, annual plant fibers retain their importance. The technical feasibility of non-woody materials is substantiated by more than 300 paper mills throughout the world that use such raw materials. Both necessity and special properties account for their use. The potential for various nonwoody fibrous plants is being investigated intensively by the United States Department of Agriculture’s Agricultural Research Service, to discover new crops that might hare practical significance in the national agricultural program and in the commercial production of paper.     

Sustaining fibers in the rock lobster

The properties of sustaining fibers (SuF's), whose firing frequency is related to the ambient light intensity, were studied in the rock lobster. Most of the firing patterns shown under various conditions were demonstrated to be physiological, by using chronic implantation techniques. Unusual activity at high light intensities suggests that the lobster visual system is equipped to function only under dim light conditions. Unlike the crayfish, the lobster SuF's do not always indicate light levels but only changes in light intensity. It is suggested that the input from these fibers has a large influence on locomotor activity.