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G C Stone

Publications and source records attributed to G C Stone.

At least 37 records · Page 2Linked to original sources
PubMed1983

Glycosylation as a criterion for defining subpopulations of fast-transported proteins.

The role carbohydrate residues may play in the sorting of newly synthesized fast-transported proteins during the initiation of fast axonal transport has been examined by identifying individual fast-transported glycoproteins that contain either or both fucose and galactose. [3H]Fucose or [3H]galactose was incorporated together with [35S]methionine in vitro in bullfrog dorsal root ganglia. Fast-transported proteins that accumulated proximal to a ligature on the spinal nerve were separated via two-dimensional gel electrophoresis, and 92 gel spots were analyzed quantitatively for the presence of 35S and 3H. Of these spots, 56 (61%) contained either or both fucose and galactose. Glycomoieties were generally associated with families of charged spots whose isoelectric points could be altered with neuraminidase treatment. Single spots tended to be unglycosylated and were unaffected by neuraminidase. The prevalence of glycoproteins was considerably greater in the higher-molecular weight range. Of the 55 spots analyzed with molecular weight greater than approximately 35,000 daltons, 89% were glycosylated, whereas only 19% of the 37 spots with lower molecular weight contained sugar moieties. When considered in light of previous studies in which similar subpopulations have been described, the current findings suggest that the presence or absence of glycomoieties may represent another criterion by which proteins are sorted during the initiation of fast axonal transport.

Animals↗
PubMed1983

Fast-transported glycoproteins and nonglycosylated proteins contain sulfate.

35SO4-labeled fast-transported proteins of bullfrog dorsal root ganglion neurons were separated by two-dimensional gel electrophoresis, and their mobilities were compared to similar species labeled with [3H]mannose or [3H]fucose. Fluorography revealed regions of poorly resolved, high molecular weight material, likely to represent sulfated proteoglycans, as well as many well resolved spots that corresponded in mobility to individual [35S]methionine-labeled fast-transported proteins. The majority of these well resolved spots appeared as "families," previously identified as glycoproteins based on their labeling with sugars. Thus, sulfate can be a contributor to the carbohydrate side-chain charge that underlies microheterogeneity. The most heavily 35SO4-labeled species, however, corresponded to fast-transported proteins that were not labeled by either sugar. The relative acid labilities of 35SO4 associated with individual species cut from the gel confirmed the assignments of these spots as glycoproteins or nonglycoproteins. A group of spots intermediate in their acid lability was also detected, suggesting that some proteins may contain sulfate linked to carbohydrate as well as to amino acid residues.

Animals↗
PubMed1982

Evidence that all newly synthesized proteins destined for fast axonal transport pass through the Golgi apparatus.

Effects of the sodium ionophore, monensin, were examined on the passage from neuronal cell body to axon of materials undergoing fast intracellular transport. In vitro exposure of bullfrog dorsal root ganglia to concentrations of drug less than 1.0 micron led to a dose-dependent depression in the amount of fast-transported [3H]leucine- or [3H]glycerol-labeled material appearing in the nerve trunk. Incorporation of either precursor was unaffected. Exposure of a desheathed nerve trunk to similar concentrations of monensin, while ganglia were incubated in drug-free medium, had no effect on transport. With [3H]fucose as precursor, fast transport of labeled glycoproteins was depressed to the same extent as with [3H]leucine; synthesis, again, was unaffected. By contrast, with [3H]galactose as precursor, an apparent reduction in transport of labeled glycoproteins was accounted for by a marked depression in incorporation. The inference from these findings, that monensin acts to block fast transport at the level of the Golgi apparatus, was supported by ultrastructural examination of the drug-treated neurons. An extensive and selective disruption of Golgi saccules was observed, accompanied by an accumulation of clumped smooth membranous cisternae. Quantitative analyses of 48 individual fast-transported protein species, after separation by two-dimensional gel electrophoresis, revealed that monensin depresses all proteins to a similar extent. These results indicate that passage through the Golgi apparatus is an obligatory step in the intracellular routing of materials destined for fast axonal transport.

Animals↗
PubMed1981

Differential effects of cobalt on the initiation of fast axonal transport.

Effects of Co2+ on the fast axonal transport of individual proteins were examined in vitro in bullfrog spinal/sciatic nerves. 35S-methionine-labeled proteins, fast-transported in control and Co2+-treated preparations were separated via two-dimensional gel electrophoresis. While the overall amount of protein transported was reduced, no qualitative differences could be seen when gel fluorographic patterns were compared. Quantitative analyses of the 48 most abundantly transported species revealed two significantly different populations (p less than 0.01) differentially sensitive to Co2+ and distinguishable to a large extent by molecular weight. Those proteins less sensitive to Co2+ ranged from approximately 20,000 to 35,000 daltons while those more sensitive to Co2+ were greater than approximately 35,000 daltons. The finding that all proteins are affected by Co2+ supports the proposal that fast-transported proteins are subject to a common Co2+-sensitive, Ca2+-requiring step. The observed differential effects are consistent with more than one Ca2+-dependent step occurring during the initiation phase of fast transport.

Animals↗
PubMed1980

Combined effects of alcohol and sleep deprivation in normal young adults.

The effect of combining sleep deprivation and moderate alcohol consumption in male college students differed from the effects of each treatment alone. Following either alcohol or sleep deprivation, there was mild performance impairment, decreased alertness and reduced amplitude and increased latency of cortical evoked potential (EP) components. Heart rate increased after alcohol and anxiety increased after sleep deprivation. When alcohol and sleep deprivation were combined, antagonistic effects were found for most measures (reaction time, heart rate, alertness, anxiety, latency of early EP components), but synergistic effects also occurred (performance accuracy, latency of late EP components). These effects were found in a double-blind experiment using 24 subjects. The experimental treatments were alcohol doses of 0, 0.45 and 0.90 ml/kg of 95% ethanol and 0 and 26 h of sleep deprivation.

Adult↗
PubMed1979

Qualitative analysis of proteins rapidly transported in ventral horn motoneurons and bidirectionally from dorsal root ganglia.

Two-dimensional electrophoresis has allowed a higher-resolution comparison of rapid transport in ventral horn motoneurons and bidirectionally in dorsal root sensory neurons. Dorsal root ganglia 8 and 9, or hemisected spinal cords, from frog were selectively exposed in vitro to 35S-methionine. Transported, labelled proteins that accumulated in 3 mm segments proximal to ligatures on dorsal roots and spinal nerves or sciatic nerves were subjected to two-dimensional gel electrophoresis. Comparisons were made of fluorographic patterns from dried gels. Sixty-five species of proteins were found to be rapidly transported in both bifurcations of dorsal root sensory neurons. No abundant species of protein was rapidly transported in dorsal roots that was not also found in spinal nerves. A comparison of proteins rapidly transported in the sciatic nerve from ventral horn motoneurons with those from dorsal root sensory neurons yielded 50 common species of polypeptides. At most four minor species were possibly transported only in ventral horn motoneurons. An overall comparison indicates that at least 45 species of proteins, including all of the more abundantly transported ones, were consistently common to both dorsal root bifuractions and to ventral horn motoneurons. This appears to be the case despite the very different functions carried out by motoneurons and sensory neurons.

Animals↗
PubMed1978

Two-dimensional gel electrophoresis of proteins in rapid axoplasmic transport.

Two-dimensional electrophoresis of proteins has allowed high resolution analysis of the protein species rapidly transported in the frog sciatic nerve. The 7th, 8th and 9th dorsal root ganglia were selectively labeled with [3H]leucine or [35S]methionine in one compartment of a lucite chamber. Transport of TCA-precipitable material was monitored in the spinal roots and sciatic nerve kept in another compartment. Fastest transport rates were 75-90 mm/day at 18 decrees C. Ligation of the nerve 30 mm distal to the 8th ganglion at the beginning of the experiment resulted in accumulation of label during a 24 h period. This material was subjected to two-dimensional electrophoresis (pI 5-8; mol.wt. 10(4)-10(5) daltons) in 3 mm nerve segments. Autoradiographs or fluorographs from segments proximal to the ligature yielded a pattern of about 140 spots. Of these, at least 60 were considered to be independent protein species. Neither actin nor tubulin were present among these rapidly-transported, labeled proteins. No pattern was observed from segments distal to the ligature. Blocking protein synthesis with 18 micrometer anisomycin reduced the accumulation of label proximal to the ligature by 98%. Direct labeling of nerve segments produced patterns significantly different from the pattern of transported proteins.

Animals↗
PubMed1978

Changes in synthesis of specific proteins following axotomy: detection with two-dimensional gel electrophoresis.

Changes in protein synthesis during development and following axotomy were analyzed by two-dimensional gel electrophoresis. The two major postganglionic nerves emerging from the superior cervical sympathetic ganglia (SCSG) of adult rats were either cut or crushed unilaterally. At intervals ranging from 1 to 112 days after surgery both SCSG were removed and incubated for 1 hr in the presence of 14C-leucine. Proteins were extracted and subjected to two-dimensional electrophoretic separation and autoradiography. With this technique, proteins are separated on the basis of isoelectric point and molecular weight. Also, intact SCSG from 1, 2, 7, and 14 day old rats were labeled and analyzed. It was found that a minority of the separated proteins exhibited some detectable change in relative rate of synthesis following axotomy. Actin exhibited a slight (less than 20%) increase in relative synthesis rate while tubulin did not change significantly. There were small but significant differences in the protein patterns following nerve crush, as opposed to nerve cut. Comparison of protein synthesis patterns from developing rat SCSG with those from intact and from axotomized adult SCSG failed to demonstrate any marked similarity between the developmental and the axotomy patterns.

Actins↗
PubMed1978

Test of some aging hypotheses using two-dimensional protein mapping.

We have compared the proteins from superior cervical sympathetic ganglia (SCSG) in young and old male Fischer rats. We have searched for the kinds of changes in protein size or charge which are predicted by such cellular aging theories as the error catastrophe theory, the somatic mutation theory, the cross-linkage theory, translational aging, the deamidation theory, and the autoimmune theory. SCSG from young (2 months to 1 year) and old (21-24 months) rats were labeled in vitro for 1 h with 14C-leucine prior to protein extraction for analysis. Protein analysis was on high-resolution, two dimensional polyacrylamide gels using O'Farrell's technique, with some modifications. Proteins were separated according to isoelectric point in one dimension and molecular weight in the second dimension. The changes predicted by the above aging theories were detected neither in the staining pattern, showing protein amounts, nor in the labeling pattern on autoradiographs of dried gels, showing newly synthesized proteins. The results suggest the possibility that, at least for rat, some other mechanisms for aging are present.

Aging↗
PubMed1977

Primitive nervous systems: peripheral habituation in decerebrate polyclad flatworms.

The response to a vibration stimulus recorded from the cords of the ventral submuscular plexus of the polyclad flatworm, Notoplana acticola, consists of a burst of action potentials. The response can be abolished by the application of MgCl2 to the sea water bathing the preparation. With repeated application of the stimulus, decreasing numbers of action potentials can be measured. This waning responsiveness can be dishabituated by applying a more intense vibration stimulus or with electrical shocks applied directly to the ventral nerve plexus. With electrical stimuli a number of shocks have to be applied before the response can be dishabituated. Changes in responsiveness can be measured simultaneously in a number of sites in the plexus even after the nerves between recording sites have been served. With different interstimulus intervals the extent of habituation changesmas interstimulus intervals increase from 1 to 5 sec, there appears to be a decrease in responsiveness which recovers when interstimulus intervals become longer than 5 sec.

Action Potentials↗
PubMed1976

The ultrastructural organization of the visual system of the wax moth, Galleria mellonella: the retina.

The ultrastructural organization of ommatidial components of the retina of the moth. Galleria mellonella are described from electron microscopic observations. Each ommatidium is composed of 12 common retinula cells and one basal eccentric cell. The retinula cells are connected together by a desmosomal strip along their length. The rhabdom occupies the basal thirty percent of the ommatidium and can be divided into nine segments of parallel microvilli. Several cells may contribute to an individual rhabdomere. The rhabdomeres are arranged in a cross with single cell rhabdomeres lying between the arms of the cross. Thin sections of ommatidium absorb polarized light differentially. The total amount of plane polarized light absorbed varies with angle of rotation for an entire ommatidium but there are also differences between the amount of absorption of adjacent rhabdomeric segments. Galleria appears to be the only lepidopteran in which the possibility of the polarized light reception has been reported.

Animals↗
PubMed1976

The ultrastructural organization of the visual system of the wax moth, Galleria mellonella: the optic tract.

The ultrastructural organization of the axons of retinula cells of the eye of the wax moth Galleria mellonella are described. The axons traverse an appreciable distance between the basement membrane of the retina and the lamina ganglionaris of the optic lobe of the brain. The optic tract was reconstructed from serial thin sections. Axons emanating from a single ommatidium are closely associated together in the optic tract. Adjacent cartridges fuse together to form large clusters of axons (8 to 10 cartridges). There is further coalescence between these large clusters. Extracellular space within the optic tract is severely limited and axons are sheathed by glial lamellae. Extracellular space between the axons and glia has been measured between 50 and 120 A. Calculations are presented that suggest that the glial interstices between the axons could increase the space constants of the axons significantly. Potentials could be transmitted along the length of the axons with between 59 to 37% decremental decrease, depending upon the number of glial interstices.

Animals↗
PubMed1976

Effects of practice on marijuana-induced changes in reaction time.

The effect of smoked marijuana on performance of complex reaction time (RT) tasks was studied in two groups receiving different amounts of practice. Group M-P had no undrugged practice on the task before performing during marijuana intoxication for four consecutive daily sessions. On the fifth test day they performed while non-intoxicated. Group P-M performed the task on four consecutive test days while non-intoxicated, then smoked marijuana on session 5. Significant RT slowing was found on session 1 for group M-P (performing during marijuana intoxication without prior practice). Performance of this group improved rapidly and by the end of session 2 was not different from undrugged performance. Group P-M (receiving four sessions of undrugged practice before marijuana intoxication) showed no RT slowing while intoxicated. Reaction time performance may involve two phases: an early, attention-demanding phase which is sensitive to drug effects and a later, "automatic", phase which results from practice and is more resistant to drug effects. Pulse rate, salivary flow and subjective responses were recorded before and after smoking. These physiological and subjective measures showed only slight reduction in the acute effects of the drug over the four days of repeated usage.

Adult↗
PubMed1975

Factor analy of orality and anality in selected patient groups.

Responses of 150 outpatients, suffering from physical or emotional problems to a 186-item questionnaire concerning their possession of behavioral traits that have been associated with anal and oral personality structures, as well as their practices and concerns about mouth and bowel function, were factor analyzed. Results were comparable with those from an earlier study involvine Army recruits as subjects, in showing some factors that resembled aspects of oral and anal character as described in psychoanalytic theory. These factors were not strong, nor were they clearly related to mouth and bowel behavior. Comparisons among clinical sub-groups showed that on five factors that significantly differentiated the groups, mean factor scores of proctological and ulcer patients resembled each other more than they did those of obsessive-compulsive patients, who were quite similar to passive-dependents. A control group of other types of psychiatric patients mixed with dermatological patients was intermediate between the physical and neurotic groups of patients. As seen in these factors, the somatic patients were relatively easy-going, slipshod, and accepting of change. Proctological and obsessive-compulsive patients, both linked to anal fixations by psychoanalytic theory, were the most dissimilar of all groups.

Anus Diseases↗