Hydrophobic affinity partition of spinach chloroplasts in aqueous two-phase systems

The surface properties of spinach chloroplasts, both of intact chloroplasts with surrounding envelope and broken chloroplasts consisting of the inner lamellar system, have been studied by partitioning them between two aqueous phases, especially using counter-current distribution technique. The two-phase system consists of poly(ethyleneglycol), dextran and water. The two polymers are enriched in opposite phases and by binding deoxycholate or palmitate to one of the polymers the affinity of chloroplasts for the corresponding phase is strongly enhanced. The partition of the two classes of chloroplasts, however, is not affected to the same degree and the affinity of the chloroplast envelope for deoxycholate and palmitate is stronger than that of the lamellar system. This has been correlated to the chemical composition of the two types of membranes. By studying the effect of salts on the partition it has been found that the lamellar system bears a larger number of negative charges as compared to the envelope of the intact chloroplast.     

The use of dispersed pancreatic islet cells in measurements of transmembrane transport

Suspensions of dispersed islet cells were prepared by shaking collagenaseisolated pancreatic islets of $\text{ob}\text{ob}\text{-}\text{mice}$ in Ca²⁺-free buffer. The dispersed cells exhibited a glucose uptake with stereospecificity for the d isomer and concentrated Rb⁺ about 30-fold from a medium containing 70 μm RbCl. These results compare well with previous observations on unbroken islets and indicate that the dispersion procedure does not cause serious damage to the plasma membranes of the β-cells. By double isotope labeling and centrifuging the incubated cells through oil, incubation times as short as only a few seconds can be used. The elimination of the extracellular tissue space and the short incubation times should facilitate the study of transport kinetics in the pancreatic islet cells.     

Formation of a functional adrenergic input to intraocular cerebellar grafts: Ingrowth of inhibitory sympathetic fibers

The intraocular transplantation technique was used to study the ingrowth of peripheral sympathetic adrenergic nerves from the iris into transplants of fetal rat cerebellum, and the possible function of these nerves. The transplants, grown in oculo for one-half to eight months, were analyzed by fluorescence histochemistry and electrophysiological techniques. Peripheral sympathetic adrenergic fibers from the iris were able to grow into the cerebellar transplants and arborize in a pattern similar to that in situ, appearing in all three cortical layers and the noncortical areas of the transplants. The density of visible nerves without pretreatment and after preincubation in 10⁻⁶ or 10⁻⁵ M α-methylnorepinephrine was comparable to mature rat cerebellum. The spontaneous discharge of the Purkinje cells in oculo was inhibited by microiontophoresis of norepinephrine (NE) and amphetamine in sympathetically innervated, as well as sympathectomized transplants denervated by ganglionectomy. The NE response was blocked by the adrenergic β-receptor blocker MJ-1999. GABA also inhibited the Purkinje cell activity while glutamate accelerated the discharge. Parenteral amphetamine inhibited Purkinje cell activity in sympathetically innervated transplants, but was ineffective in denervated transplants. The Purkinje cell spontaneous activity was inhibited by electrical stimulation of the NE fiber input through the cervical sympathetic trunk. This inhibition could be antagonized by parenteral reserpine or the β-adrenergic antagonist propranolol. The responses of the Purkinje cells within the transplants to drugs and transmitters mimic those of the adult rat in situ. In view of the fluorescence histochemical evidence for an ingrowth of peripheral sympathetic adrenergic fibers into the cerebellar transplants, and the results of stimulating the sympathetic trunk, it is suggested that peripheral adrenergic fibers may be able to establish functional connections with the Purkinje cells similar to the cerebellar adrenergic synapses normally formed in situ by fibers from the locus coeruleus.     

Chemical action of influenza virus on the red blood cell membrane. II. Action on membrane lipids and amino acids.

Haemagglutination by influenza virus strains PR8 and Lee as well as treatment of red blood cells by periodate produced numerous and manifold changes in the lipids and the amino acid composition of the erythrocytes. The changes induced by the influenza strains differed from each other and from those induced by periodate. Alterations in the membrane lipids observed after haemagglutination by heat treated strain PR8 and by its native form were identical.     

Purification and properties of myosin from the "hatching muscle" (m. complexus) of geese

The present work is concerned with the study of myosin fractions prepared from the hatching muscle (m. complexus) and a control muscle (m. pectoralis) of the developing goose embryo. The m. complexus attained its maximum mass at hatching and in the 4-day-old bird the mass of this muscle was only one fourth of that recorded at hatching. The m. complexus was hypertrophied already on the 21st day. At days 21, 27 and 28 of incubation and at posthatching days myosin preparations were made from both muscles. Partial purification of myosins from both sources yielded a high molecular weight fraction characteristic of the adult bird and one other protein fraction with molecular mass half of myosin. Both preparations exhibited the characteristic properties of myosin. The lower molecular weight fraction was also shown to develop filamentous aggregates as did the higher molecular-weight, gel filtrated myosin. The phosphate content of the half molecular mass myosin fraction prepared from the embryonic m. complexus at days prior to hatching was considerably higher than that of the high molecular weight fraction and the predominant component was P-Arg. Since the embryonic myosin was still not available in the m. complexus of the 4-day-old birds and the hypertrophied muscle underwent regression after hatching it appears that this myosin fraction is actively involved in breaking through the shell during the hatching period in geese.     

Establishment of modern examining procedures for diagnosis of porphyrias

Reversed-phase high-performance liquid chromatography together with fluorescence detection is suitable for the determination of urinary porphyrin carboxylic acid isomers, and Copro I and III, as well as Uro I and III porphyrin isomers are separated simultaneously.