bluuebunny/crossref_metadata_2025 huggingface dataset:
Ectomycorrhizal fungi and interspecific competition: species interactions, community structure, coexistence mechanisms, and future research directions
Authors: Kennedy Peter
Published: July 2010

The field of ectomycorrhizal fungal (EMF) ecology has largely developed outside the ecological mainstream, owing in large part to the challenges in studying the structure and dynamics of EMF communities. With advances in molecular identification and other research techniques, however, there has been growing interest among mycologists and ecologists in understanding how different ecological factors affect EMF community structure and diversity. While factors such as soil chemistry and host specificity have long been considered important, an increasing number of laboratory and field studies have documented that interspecific competition also has a major impact on EMF species interactions and may significantly influence EMF community structure. In this review, I examine the progress that has been made in understanding the nature of EMF competition. Currently, there are four conclusions that can be drawn: negative competitive effects are rarely reciprocal; competitive outcomes are environmentally context‐dependent; field distributions often reflect competitive interactions; and timing of colonization influences competitive success. In addition, I highlight recent studies documenting links between competitive coexistence and EMF community structure, including checkerboard distributions, lottery models, storage effects, and colonization–competition tradeoffs. Finally, I discuss several aspects of EMF competition needing further investigation and some newer methods with which to address them.

Contents

Summary
895

I.
Introduction
896

II.
Definitions and terminology
897

III.
Patterns of EMF competition
897

IV.
How do EMF competitors coexist?
902

V.
Unanswered questions and future directions
904

VI.
New methods and approaches
905

VII.
Conclusions
907

Acknowledgements
907

References
907
THE ISOLATION AND LIPID COMPOSITION OF MYELIN‐FREE AXONS FROM RAT CNS1
Authors: Vries G. H. De , Hadfield M. G. , Cornbrooks C.
Published: July 2010

—Myelin‐free axons were isolated from rat CNS using a modification of the method of De Vrieset al. (1972). On a dry weight basis, the axons contained 15·2% lipid composed of 19·4% cholesterol, 56·9% phospholipid and 23·7% galactolipid with a weight ratio of cerebroside to sulfatide of 3·6‐1. The phospholipid was composed of 11·0% ethanolamine phosphatides (44·4% in the plasmalogen form), 21·0% choline phosphatides (9·3% in the plasmalogen form), 4·5% sphingomyelin, 4·5% phosphatidyl serine, 4·3% phosphatidyl inositol, 3·0% diphosphatidyl glycerol and 8·5% unidentified phospholipid. The rat axons contained 0·18 μg ganglioside NeuNAc/mg dry wt. In addition to the 4 major brain gangliosides, the rat axons contained gangliosides GD2 and GD3. The axonal galactolipid could not be accounted for by myelin contamination as revealed by electron microscopy, absence of the characteristic ratio of myelin specific proteins in the axonal protein profile as shown by polyacrylamide gel electrophoresis, and the axonal level of the myelin marker enzyme 2′,3′‐cyclic nucleotide‐3′‐phosphohydrolase. The relationship between lipids of axons isolated from rat and bovine CNS, and rat whole brain and CNS myelin is discussed.
MOLECULAR PROPERTIES OF CHOLINE ACETYLTRANSFERASE FROM DIFFERENT SPECIES INVESTIGATED BY ISOELECTRIC FOCUSING AND ION EXCHANGE ADSORPTION
Authors: Malthe‐Sørenssen D.
Published: July 2010

—The isoelectric point, surface charge and Km for choline of choline acetyltransferase from different species were determined. Choline acetyltransferase from mouse and monkey brain was resolved into three molecular forms with isoelectric points at 7·1, 7·5, 8·4 and 7·0, 7·35, 8·35 respectively, whereas choline acetyltransferase from the electric organ of Torpedo and from rabbit brain showed a molecular form with isoelectric point 6·6 and 6·9, respectively. With the exception of rabbit brain enzyme, there was a good correlation between the isoelectric points and surface charges of the different choline acetyltransferases. The Km's for choline were 0·66, 0·88, 0·92 and 3·5 mM for monkey, mouse, rabbit and Torpedo choline acetyltransferase respectively. The separated molecular forms of mouse and monkey enzymes did not show any significant difference in their affinity for choline.
Local Anesthetics Inhibit the Ca2+,Mg2+‐ATPase Activity of Rat Brain Synaptosomes
Authors: Garcia‐Martin Elena , Gutiérrez‐Merino Carlos
Published: July 2010

Abstract: Many biochemical effects of local anesthetics are expressed in Ca2+‐dependent processes [Volpi M., Sha'afi R. I., Epstein P. M., Andrenyak P. M., and Feinstein M. B. (1981) Proc. Natl. Acad. Sci. USA 78, 795–799]. In this communication we report that local anesthetics (dibucaine, tetracaine, lidocaine, and procaine and the analogue quinacrine) inhibit the Ca2+‐dependent and the Mg2+‐dependent ATPase activity of rat brain synaptosomes and of membrane vesicles derived from them by osmotic shock. This inhibition is induced by concentrations of these drugs close to their pharmacological doses, and a good correlation between K0.5 of inhibition and their relative anesthetic potency is found. The Ca2+‐dependent ATPase is more selectively inhibited at lower drug concentrations. The physiological relevance of these findings is discussed briefly.
Ectonucleotidase Activities Associated with Cholinergic Synaptosomes Isolated from Torpedo Electric Organ
Authors: Grondal E. J. M. , Zimmermann H.
Published: July 2010

Abstract: Intact synaptosomes isolated from the electric organ of the electric ray Torpedo marmorata contain, at their surface, enzyme activities for the hydrolysis of externally applied nucleoside phosphates. The diazonium salt of sulfanilic acid, as a low‐molecular‐weight, slowly permeating, covalent inhibitory agent, selectively blocks these enzyme activities and leaves intracellular lactate dehydrogenase intact. The ectoenzymes comprise both a nucleoside triphosphate and diphosphate phosphohydrolase, as well as a 5′‐nucleotidase. Activity of nonspecific ectophosphatases is absent. The nucleoside triphosphatase hydrolyzes almost equally well ATP, GTP, CTP, UTP, and ITP and is activated to a similar degree by Mg2+ or Ca2+. It has a high affinity for ATP (Km for ATP in the presence of Mg2+, 75 μM; in the presence of Ca2+, 66 μM). Maximal rates in the presence of Mg2+ and Ca2+ were very similar (34.8 and 32.5 nmol of P/min/mg of synaptosomal protein, respectively). Either Mg‐ATP or Ca‐ATP can act as a true substrate. ADP inhibits hydrolysis of ATP, but AMP is without effect. The nucleoside triphosphatase is not inhibited significantly by a number of inhibitors of mitochondrial Mg2+‐ATPase or of Ca2++ Mg2+‐ATPases. It is, however, considerably inhibited by filipin and quercitin. The capacity of intact synaptosomes to hydrolyze also extracellular ADP, GDP, AMP, GMP, and IMP suggests that the nucleoside triphosphatase is part of an enzyme chain that causes complete hydrolysis of the respective nucleoside triphosphate to the nucleoside. We conclude that the cholinergic nerve terminals of the Torpedo electric organ can hydrolyze ATP released on coexocytosis with acetylcholine via an ectonucleoside triphosphatase activity that is different from known endogenous nerve terminal ATPases. The final product of the hydrolysis, adenosine, can then be salvaged by the nerve terminal for resynthesis of ATP. Other possible physiological functions of the ectonucleotidases are discussed.
β,β′‐Iminodipropionitrile Impairs Retrograde Axonal Transport
Authors: Fink David J. , Purkiss David , Mata Marina
Published: July 2010

Abstract β,β′‐Iminodipropionitrile (IDPN), a neurotoxin, causes redistribution of neurofilaments in axons followed by the development of proximal axonal swellings and, in chronic intoxication, a distal decrease in axonal caliber. The latter changes are caused by a selective impairment in the slow anterograde axonal transport of neurofilament proteins. To assess the role of retrograde axonal transport in IDPN toxicity, we used [3H]N‐succinimidyl propionate ([3H]NSP) to label covalently endogenous axonal proteins in sciatic nerve of the rat and measured the accumulation of radioactively labeled proteins in the cell bodies of motor and sensory neurons over time. IDPN was injected intraneurally 6 h or intraperitoneally 1 day before subepineurial injection of [3H]NSP into the sciatic nerve, and the animals were killed 1, 2, and 7 days after [3H]NSP injection. Neurotoxicity was assessed by electron microscopic observation of the nerves of similarly treated animals. Both intraneural and intraperitoneal injection of IDPN caused an acute reduction in the amount of labeled proteins transported back to the cell bodies. The early appearance of these changes suggests that alterations in retrograde transport may play a role in the production of the neuropathic changes.
Anterograde Components of Axonal Transport in Motor and Sensory Nerves in Experimental 2,5‐Hexanedione Neuropathy
Authors: Brændgaard Hans , Sidenius Per
Published: July 2010

Anterograde slow and fast axonal transport was examined in rats intoxicated with 2,5‐hexanedione (1 g/kg/week) for 8 weeks. Distribution of radioactivity was measured in 3‐mm segments of the sciatic nerve after labelling of proteins with [35H]methionine or [3H]Ieucine and glycoproteins with [3H]fucose. The axonal transport of the anterograde slow components was examined after 25 (SCa) and 10 days (SCb), in motor and sensory nerves. SCa showed an increased transport velocity in motor (1.25 ± 0.08 mm/day versus 1.01 ± 0.05 mm/day) and in sensory nerves (1.21 ± 0.13 mm/day versus 1.06 ± 0.07 mm/day). The relative amount of labelled protein in the SCa wave in both fiber systems was also increased. SCb showed unchanged transport velocity in motor as well as in sensory nerves, whereas the amount of label was decreased in the motor system. Anterograde fast transport in motor nerves was examined after intervals of 3 and 5 h, whereas intervals of 2 and 4 h were used for sensory nerves. Velocities and amounts of labelled proteins of the anterograde fast component remained normal. We suggest that the increase in protein transport in SCa reflects axonal regeneration.
In Vivo Release of Endogenous Amino Acids from the Rat Striatum: Further Evidence for a Role of Glutamate and Aspartate in Corticostriatal Neurotransmission
Authors: Girault Jean Antoine , Barbeito Luis , Spampinato Umberto , Gozlan Henri , Glowinski Jacques , Besson Marie‐Jo
Published: July 2010

By means of the push‐pull cannula method, the outflow of endogenous amino acids was studied in the striatum of halothane‐anesthetized rats. Addition of K + ions (30 mM for 4 min) to the superfusion fluid increased the release of aspartate (+116%), glutamate (+ 217%), taurine (+109%), and γ‐aminobutyric acid (GABA) (−429%) whereas a prolonged decrease in the outflow of glutamine (−28%) and a delayed reduction in the efflux of tyrosine (−25%) were observed. In the absence of Ca2‐, the K+‐induced release of aspartate, glutamate, and GABA was blocked whereas the K + ‐induced release of taurine was still present. Under these conditions, the decrease in glutamine efflux was reduced and that of tyrosine was abolished. Local application of tetrodotoxin (5 μM) decreased only the outflow of glutamate (‐25%). One week following lesion of the ipsilateral sensorimotor cortex the spontaneous outflow of glutamine and of tyrosine was enhanced. Despite the lack of change in their spontaneous outflow, the K +‐evoked release of aspartate and glutamate was less pronounced in lesioned than in control animals, whereas the K + ‐evoked changes in GABA and glutamine efflux were not modified. Our data indicate that the push‐pull cannula method is a reliable approach for the study of the in vivo release of endogenous amino acids. In addition, they provide further evidence for a role for glutamate and aspartate as neuro‐transmitters of corticostriatal neurons.
Regional Amino Acid Concentration in the Brains of Rats Exposed to High Pressures
Authors: Chapman Astrid G. , Halsey Michael J. , Hart Geneen P. , Luff Nigel P. , Meldrum Brian S. , Wardley‐Smith Bridget
Published: July 2010

Regional amino acid concentrations were measured in rat brain fixed by microwave irradiation at three levels of elevated atmospheric pressure corresponding to different phases of the high‐pressure neurological syndrome [20 atmospheres absolute (ATA), no clinical signs; 60 ATA, tremor; 85 ATA, severe tremor and myoclonic jerks]. No changes in amino acid content occurred at 20 or 60 ATA. At 85 ATA glutamine content increased in hippocampus, striatum, cerebellum, and substantia nigra, and γ‐aminobutyric acid content increased in hippocampus. It is suggested that enhanced glutamate release in various subcortical structures contributes to the myoclonic activity observed at 85 ATA.
Jimpy Mice: Quantitation of Myelin‐Associated Glycoprotein and Other Proteins
Authors: Yanagisawa Katsuhiko , Quarles Richard H.
Published: July 2010

Myelin‐associated glycoprotein (MAG), 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase (CNPase) activity, myelin basic protein (BP), and proteolipid protein (PLP) were quantitated in the brains of 20‐day‐old Jimpy and control mice. The levels of MAG, CNPase, and BP in Jimpy brains were 5.3%, 9.7%, and 1.9% of those in control brains, respectively. Immunoblotting analysis did not reveal an increased apparent Mr for MAG in the Jimpy mouse, as has been observed in some other hypomyelinating murine mutants. PLP was reduced more than the other proteins, as it was not detected by an immunoblotting technique that was capable of detecting 0.5% of the control level.
Differential Calcium Dependence of γ‐Aminobutyric Acid and Acetylcholine Release in Mouse Brain Synaptosomes
Authors: Arias Clorinda , Tapia Ricardo
Published: July 2010

Abstract: The dependence of γ‐aminobutyric acid (GABA) and acetylcholine (ACh) release on Ca2+ was comparatively studied in synaptosomes from mouse brain, by correlating the influx of 45Ca2+ with the release of the transmitters. It was observed that exposure of synaptosomes to a Na+ ‐free medium notably increases Ca2+ entry, and this condition was used, in addition to K+ depolarization and the Ca2+ ionophore A23187, to stimulate the influx of Ca2+ and the release of labeled GABA and ACh. The effect of ruthenium red (RuR) on these parameters was also investigated. Of the three experimental conditions used, the absence of Na+ in the medium proved to be the most efficient in increasing Ca2+ entry. RuR inhibited by 60–70% the influx of Ca2+ stimulated by K+ depolarization but did not affect its basal influx or its influx stimulated by the absence of Na+ or by A23187. The release of ACh was stimulated by K+ depolarization, absence of Na+ in the medium, and A23187 in a strictly Ca2+‐dependent manner, whereas the release of GABA was only partially dependent on the presence of Ca2+ in the medium. The extent of stimulation of ACh release was related to the extent of Ca2+ entry, whereas no such correlation was observed for GABA. In the presence of Na+, RuR did not affect the release of the transmitters induced by A23187. In the absence of Na+, paradoxically RuR notably enhanced the release of both ACh and GABA induced by A23187, in a Ca2+‐dependent manner. These results are discussed in terms of a possible A23187‐induced inward transport of RuR into the synaptosomes, which would result in an inhibition of the trapping of Ca2+ by intraterminal stores. It is concluded that Na + participates in the regulation of the permeability to Ca2+ in synaptosomes. The release of ACh requires an increase in the concentration of cytosolic Ca2+, whereas a large proportion of GABA can be released, in addition to this Ca2+ ‐dependent mechanism, by a different one that does not require this cation. The possibility that such mechanism is related to Na+ is discussed.
Effects of Postdecapitative Ischemia on Mitochondrial Respiration in Brain Tissue Homogenates
Authors: Sims Neil R. , Finegan Janet M. , Blass John P.
Published: July 2010

Abstract: Mitochondria isolated from ischemic brain characteristically show changes in respiratory function. As conventional procedures for mitochondrial isolation yield a subpopulation of the total population and require extensive manipulation, it is unclear to what extent these changes are representative of mitochondria in the unfractionated tissue. We previously showed that the oxygen uptake by unfractionated forebrain homogenates, measured under two different sets of incubation conditions, provided information on some aspects of the respiratory activity of both the free and synaptosomal pools of mitochondria. Forebrain homogenates from animals subjected to 30 min of postdecapitative ischemia exhibited large reductions in oxygen uptake rates measured in a high K+ (mitochondrial) buffer in the presence of either ADP (44% of control values) or an uncoupling agent (45% of control values). These reductions in respiratory activity were comparable to alterations observed under the same conditions for mitochondria isolated from the ischemic brains. Similar alterations were seen in homogenates from three subregions: neocortex, hippocampus, and striatum. In a physiological buffer, in which oxygen uptake by homogenates largely resulted from activity of mitochondria within synaptosomes, there was little or no change in basal glucose‐supported rates (79–96% of control values) and small reductions in maximal rates (63–81% of control values) measured in the presence of an uncoupling agent. These results suggest that alterations of respiratory function seen in isolated free mitochondria provide appropriate estimates of the dysfunction in the total free mitochondrial pool but that synaptosomal mitochondria may be less affected. Measurements of respiratory function of isolated synaptosomes from ischemic tissue provided further support for the relative preservation of synaptosomal mitochondria during ischemic insult.
Further Characterization of a Myelin‐Associated Neuraminidase: Properties and Substrate Specificity
Authors: Saito Megumi , Yu Robert K.
Published: July 2010

Abstract: A neuraminidase activity in myelin isolated from adult rat brains was examined. The enzyme activity in myelin was first compared with that in microsomes using N‐acetylneuramin(α2 → 3)lactitol (NL) as a substrate. In contrast to the microsomal neuraminidase which exhibited a sharp pH dependency for its activity, the myelin enzyme gave a very shallow pH activity curve over a range between 3.6 and 5.9. The myelin enzyme was more stable to heat denaturation (65°C) than the microsomal enzyme. Inhibition studies with a competitive inhibitor, 2,3‐dehydro‐2‐deoxy‐N‐acetylneuraminic acid, showed the Ki value for the myelin neuraminidase to be about one‐fifth of that for the microsomal enzyme (1.3 × 10−6M versus 6.3 × 10−6M). The apparent Km values for the myelin and the microsomal enzyme were 1.3 × 10−4M and 4.3 × 10−4M, respectively. An enzyme preparation that was practically devoid of myelin lipids was then prepared and its substrate specificity examined. The “delipidated enzyme” could hydrolyze fetuin, NL, and ganglioside substrates, including GM1, and GM2. When the delipidated enzyme was exposed to high temperature (55°C) or low pH (pH 2.54), the neuraminidase activities toward NL and GM3 decreased at nearly the same rate. Both fetuin and 2,3‐dehydro‐2‐deoxy‐N‐acetylneuraminic acid inhibited NL and GM3 hydrolysis. With 2,3‐dehydro −2‐deoxy‐N‐acetylneuraminic acid, inhibition of NL was greater than that of GM3; however, the Ki values for each substrate were almost identical. GM3 and GM1, also competitively inhibited the hydrolysis of NL and NL similarly inhibited GM3 hydrolysis by the enzyme. These results indicate that rat brain myelin has intrinsic neuraminidase activities toward nonganglioside as well as ganglioside substrates, and that these two enzyme activities are likely catalyzed by a single enzyme entity.
Characterization of Ca2+/Calmodulin‐Dependent Protein Kinase Associated with Rat Cerebral Synaptic Junction: Substrate Specificity and Effect of Autophosphorylation
Authors: Suzuki Tatsuo , Tanaka Ryo
Published: July 2010

Abstract: The Ca2+/calmodulin (CaM)‐dependent protein kinase associated with rat cerebral synaptic junction (SJ) was characterized, using the SJ fraction as the enzyme preparation, to clarify the functional significance of the enzyme in situ. The protein kinase was greatly activated in the presence of micromolar concentrations of both Ca2+ and calmodulin (EC50 for Ca2+, 1.0 μM; that for CaM, 100 nM). The Km for ATP was 150 μM. SJ proteins were phosphorylated without a lag time, and the phosphorylation reached its maximum within 2–10 min at 25°C. The endogenous substrates consisted of four major (160K, 120K, 60K, and 51K Mr) and 10 minor proteins. Compared with the endogenous substrate phosphorylation, the phosphorylation of exogenously added proteins (myosin light chains from chicken muscle, casein, arginine‐rich histone, microtubule‐associated protein‐2, τ‐protein, and tubulin) was weak, although they are expected to be good substrates for the soluble form of the Ca2+/CaM‐dependent protein kinase. Autophosphorylation of the enzyme in SJ inhibited its activity and did not alter the subcellular distribution of the enzyme.
Neural Control of Muscle Androgen Receptors
Authors: Bernard Phyllis A. , Max Stephen R.
Published: July 2010

The number of cytosolic androgen receptors in rat skeletal muscle increases following denervation and disuse. This increase was postulated to represent altered intracellular distribution and consequent diminished sensitivity of skeletal muscle to androgens. To test this hypothesis, we measured total (homogenate) androgen receptor levels after denervation. Total (homogenate) androgen receptor binding did not change in response to denervation of leg muscles from adult male rats. An increase in cytosolic receptor number with no increase in total (homogenate) receptor levels supports the hypothesis of altered intracellular distribution of androgen receptors in denervated muscle. Cytosolic androgen receptor binding in muscle from male rats increased by 40% after denervation, whereas in females the increase was 17% These increases could not be altered by endocrine manipulations of males or females.
A Casein Kinase‐Like Kinase Phosphorylates β‐Tubulin and May Be a Microtubule‐Associated Protein
Authors: Crute Barbara E. , Van Buskirk Robert G.
Published: July 2010

Abstract: The hypothesis that casein kinase II (CKII) is a microtubule‐associated protein kinase was investigated using a neuronal cell line and bovine brain. Heparin, an inhibitor of CKII, inhibited the phosphorylation of a PC12 cytosolic protein whose molecular weight was similar to that of β‐tubulin. Partially purified PC12 CKII was immunoreactive to an antibody directed against bovine CKII and was able to phosphorylate purified β‐tubulin in a heparin‐inhibitable manner when the concentration of tubulin was less than 50 μg/ml. To better determine if CKII is a microtubule‐associated protein kinase, bovine brain tubulin was chromatographed on FPLC Mono Q and phosphocellulose columns. Several tubulin casein kinase (TCK) activities were apparent. All TCK activities phosphorylated tubulin and casein, but none was able to phosphorylate the CKII‐specific synthetic peptide RRREEETEEE. One of these TCK fractions was immunoreactive to the antibody directed against CKII, and this antibody labeled a 50‐kDa molecular mass band that had a molecular mass distinctly different from those of the subunits of CKII. Thus, we suggest that a CKII‐like protein, but not CKII, might be a microtubule‐associated protein.
Nicotinic Agonists, Phorbol Esters, and Growth Factors Activate Two Extracellular Signal‐Regulated Kinases, ERK1 and ERK2, in Bovine Chromaffin Cells
Authors: Pavlović‐Šurjančev Biljana , Cahill Anne L. , Perlman Robert L.
Published: July 2010

Abstract: Treatment of bovine chromaffin cells with nicotinic agonists, phorbol esters, and growth factors increases protein kinase activity toward microtubule‐associated protein‐2 and myelin basic protein (MBP) in vitro. To characterize the kinases that are activated by these agents, we separated chromaffin cell proteins by electrophoresis in sodium dodecyl sulfate‐polyacrylamide gels into which MBP had been incorporated, allowed the proteins to renature, and then assayed MBP kinase activity by incubating the gels with [γ‐32P]ATP. Chromaffin cells contain a family of kinases that phosphorylate MBP in vitro. Two of these kinases, of Mr 46,000 and 42,000 (PK46 and PK42), were activated by treatment of the cells with dimethylphenylpiperazinium (DMPP), phorbol 12,13‐dibutyrate (PDBu), or insulin‐like growth factor I (IGF‐I). Activation of PK46 and PK42 by DMPP was dependent on extracellular Ca2+, whereas the effects of PDBu and IGF‐I were Ca2+ independent. Down‐regulation of protein kinase C by incubation of the cells with PDBu abolished the activation of PK46 and PK42 by DMPP, PDBu, and IGF‐I. Staurosporine, a protein kinase C inhibitor, prevented the activation of PK46 and PK42 by DMPP and PDBu but did not block the activation of these kinases by IGF‐I. Immunoblotting experiments with antiphosphotyrosine (anti‐PTyr) antibodies demonstrated that agents that increased the kinase activities of PK46 and PK42 also increased the apparent PTyr content of Mr 46,000 and 42,000 proteins. PK46 and PK42 comigrated with proteins that reacted with antibodies against extracellular signal‐regulated kinases (ERKs). Thus, PK46 and PK42 appear to be the bovine homologues of ERK1 and ERK2. These kinases are regulated by multiple pathways and may play a role in the mechanism by which a variety of agonists regulate chromaffin cell function.
Glycation of Brain Actin in Experimental Diabetes
Authors: Pekiner Can , Cullum Nicola A. , Hughes J. Neil , Hargreaves Alan J. , Mahon J. , Casson Ian F. , McLean W. Graham
Published: July 2010

Abstract: Actin is a neuronal protein involved in axonal transport and nerve regeneration, both of which are known to be impaired in experimental diabetes. To determine if actin is subject to glycation, we rendered rats diabetic by injection of streptozotocin. Two or 6 weeks later brains were removed and a preparation of cytoskeletal proteins was analyzed by two‐dimensional polyacrylamide gel electrophoresis. Brains from diabetic animals contained an extra polypeptide that migrated close to actin and reacted with monoclonal antibody C4 against actin. It was also found in a preparation of soluble synaptic proteins from diabetic rat brain, indicating that it was at least partly neuronal in origin. This polypeptide could be produced by incubation of cytoskeletal proteins from brains of nondiabetic rats with glucose‐6‐phosphate in vitro. The appearance of this glycated actin in diabetic animals was prevented by administration of insulin for a period of 6 weeks. We could not detect any effect of glycation in vitro on the ability of muscle G‐actin to form F‐actin filaments and its significance for the function of actin remains to be determined. The finding that glycation of platelet‐derived actin from diabetic patients was significantly increased implies that the abnormality may also occur in clinical diabetes.
Fucosyl‐GM1 in Human Sensory Nervous Tissue Is a Target Antigen in Patients with Autoimmune Neuropathies
Authors: Yoshino Hiide , Ariga Toshio , Latov Norman , Miyatake Tadashi , Kushi Yasunori , Kasama Takeshi , Handa Shizuo , Yu Robert K.
Published: July 2010

Abstract: Several gangliosides of human nervous tissues have been reported to be potential target antigens in autoimmune neuropathies. To explain the diversity of clinical symptoms in patients with antiganglioside antibodies, we have searched for ganglioside antigens that are specific to individual nervous tissues such as motoneurons, peripheral motor nerves, and sensory nerves. Although the major ganglioside compositions were not different among human peripheral motor and sensory nerves, fucosyl‐GM1 was found to be expressed in sensory nervous tissue but not in spinal cord, motor nerve, and sympathetic ganglia. Sera from several patients with sensory nerve involvement also reacted with fucosyl‐GM1 as well as GM1. Thus, fucosyl‐GM1 may be a responsible target antigen for developing sensory symptoms in some patients with autoimmune neuropathies.
A Purine Analog‐Sensitive Protein Kinase Activity Associates with Trk Nerve Growth Factor Receptors
Authors: Volonté Cinzia , Loeb David M. , Greene Lloyd A.
Published: July 2010

Abstract: Previous studies showed that purine analogs block with varying efficiency and specificity certain effects of nerve growth factor (NGF) on PC12 cells. These compounds also inhibit protein kinase activities. The analog 6‐thioguanine has thus far been shown to inhibit only protein kinase N, an NGF‐activated protein kinase, whereas 2‐aminopurine also blocks other kinases. In the present study, immunoprecipitates of Trk NGF receptors from PC12 cells (NGF treatment) were assayed for protein kinase activity by using the substrates myelin basic protein and histone HF1 under phosphorylating conditions optimal for protein kinase N and in the presence or absence of purine analogs. Activity was detected and ∼50–80% was inhibited by these compounds. The purine analog‐sensitive activity was maximally stimulated by NGF within 5 min, was partially decreased by 10 min, and still remained over basal levels after 15 h of NGF treatment. Analysis of myelin basic protein phosphorylated by anti‐Trk immunoprecipitates revealed an NGF‐stimulated increase in phosphothreonine and phosphotyrosine. Phosphorylation of threonine, but not of tyrosine residues, was inhibited by 6‐thioguanine, which therefore inhibits a serine/threonine kinase associated with NGF receptor rather than the receptor kinase itself. Neither 2‐aminopurine nor 6‐thioguanine inhibited the NGF‐dependent induction of Trk‐associated kinase activity. Our findings thus indicate association of a purine analog‐sensitive serine/threonine protein kinase activity with Trk NGF receptors.
Structural Properties of the Myelin‐Associated Glycoprotein Ectodomain
Authors: Attia John , Hicks Les , Oikawa Kimio , Kay Cyril M. , Dunn Robert J.
Published: July 2010

Abstract: Myelin‐associated glycoprotein (MAG) has been proposed to mediate adhesive interactions during myelin development. We have used the baculovirus expression system to produce a truncated form of this molecule [soluble extracellular domain of MAG (sMAG)] consisting of the complete extracellular ectodomain. Spectroscopic studies indicate a high β‐sheet content, consistent with the prediction of Ig‐like structure. Hydrodynamic studies indicate an asymmetric monomer, with a Stokes radius of 4.1–4.6 nm, a sedimentation coefficient of 3.6S, and a frictional ratio of ∼1.6. We postulate that the outer two Ig‐like domains form a unit that folds back over the rest of the molecule. Fluorescence quenching studies indicate that sMAG interacts with divalent cations and may have a functional lectin domain.
The History of Neurochemistry as Revealed by the Journal of Neurochemistry
Authors: Curzon G.
Published: July 2010

Abstract: Analyses of samples of articles in the Journal of Neurochemistry between 1956 (the year of its foundation) and 1990 were used to obtain numerical indices of the history of neurochemistry. Data suggest that the acceleration of neurochemical research did not merely reflect the increase of biochemical research in general and that it involved progressive decreases and increases of interest in major constituents and transmitters, respectively, as indicated by both numbers and citations of papers. Papers on all classes of transmitters increased steadily and in the order of amines > amino acids, acetylcholine > peptides. Within the field of brain metabolism, papers on energy metabolism decreased markedly. Use of techniques other than those of biochemistry/neurochemistry altered strikingly with decreases of histological, electrophysiological, and pharmacological methods and increases of chemical, immunological, and tissue culture methods. Citations by neuroscience core journals between 1975 and 1988 suggest that the relative prominence of neurochemistry within neuroscience has remained constant. Analyses indicate that the influence of the U.S.A. relative to that of other regions has remained fairly steady between 1956 and 1990, but that number of papers from the U.K. has declined, whereas the influences of Western Europe and other areas appear to have recently increased substantially. Sociological changes have been the virtual disappearance of single‐author papers, an increase of multiauthorship (>3), and a recent striking increase of assertive sentence titles.
Amyloid suppresses induction of genes critical for memory consolidation in APP + PS1 transgenic mice
Authors: Dickey Chad A. , Gordon Marcia N. , Mason Jerimiah E. , Wilson Nedda J. , Diamond David M. , Guzowski John F. , Morgan Dave
Published: July 2010

Mice transgenic for mutated forms of the amyloid precursor protein (APP) plus presenilin‐1 (PS1) genes (APP + PS1 mice) gradually develop memory deficits which correlate with the extent of amyloid deposition. The expression of several immediate‐early genes (IEGs: Arc, Nur77 and Zif268) and several other plasticity‐related genes (GluR1, CaMKIIα and Na‐K‐ ATPase αIII) critical for learning and memory was normal in young APP + PS1 mice preceding amyloid deposition, but declined as mice grew older and amyloid deposits accumulated. Gene repression was less in APP + PS1 mouse brain regions that contain less Aβ and in APP mice compared with APP + PS1 mice, further linking the extent of amyloid deposition and the extent of gene repression. Critically, we demonstrated that amyloid deposition led specifically to impaired induction of the IEGs with no effects on basal expression using exposure to a novel environment 30 min prior to being killed to induce IEGs. These data imply that Aβ deposition can selectively reduce expression of multiple genes linked to synaptic plasticity, and provide a molecular basis for memory deficiencies found in transgenic APP mice and, most likely, in early stage Alzheimer's disease (AD). Presumably, pharmacological agents blocking the Aβ‐related inhibition of gene expression will have benefit in AD.
The Production of Fast Shades on Knitted Cotton Fabrics, Nets and Lace*
Authors: WILTSHIRE E. R.
Published: July 2010

Methods of dyeing vat and Soledon dyes on knitted cotton fabrics, nets and lace on the winch machine are described. Means of overcoming frothing and oxidation difficulties with vat dyes are suggested, and a general method for dyeing a selection of the faster‐to‐light Soledon dyes without removal from the winch, based on washing between dyeing and developing, is described.
4‐Chloro‐2‐aminophenol‐5‐ and ‐6‐sulphonic Acids, their Characterisation and Differentiation
Authors: Gaunt J. F. , Rowe F. M. , Speakman J. B.
Published: July 2010

Owing to the similarity in the properties of pairs of dyes made by coupling diazotised 4‐chloro‐2‐aminophenol‐5‐ and ‐6‐sulphonic acids with the same coupling component, the identity of the former compound was open to suspicion. Consequently, 4‐chloro‐2‐aminophenol‐5‐sulphonic acid has been prepared by sulphonating 5‐chlorobenzoxazolone and then hydrolysing the 5‐chloro‐benzoxazolone‐6‐Bulphonic acid. 4‐Chloro‐2‐aminophenol‐5‐ and 6‐sulphonic acids have been characterised by conversion into 5‐chlorobenzoxazolone‐6‐ and ‐7‐sulphonic acids, from which the S‐benzylthiuronium and p‐toluidine salts were prepared. These derivatives possess satisfactory melting points and are suitable for the identification of 4‐chloro‐2‐aminophenol‐5‐ and ‐6‐sulphonic acids. The preparation of 2‐amino‐phenol‐5‐sulphonic acid from o‐aminophenol via benzoxazolono is described, and 2‐aminophenol‐4‐ and ‐5‐sulphonic acids also are readily identified by means of their S‐benzylthiuronium and p‐toluidine salts.
The Action of Ultra–violet Radiation on Proteins
Authors: ROBERTS R.
Published: July 2010

The action of ultra–violet radiation on serum–albumin has been studied. In nitrogen polymerisation occurs, but in oxygen there is a degradation of the protein molecule. The polymerisation takes place by a free–radical mechanism. The degradation in oxygen is due to photo–oxidation by hydroxyl radicals.
The Photochemical Formation of Atoms and Radicals in Aqueous Solution
Authors: EVANS M. G. , Uri N.
Published: July 2010

Atoms or free radicals (OH, Cl, F, N3 etc.) are formed by irradiation of aqueous solutions of ion pair complexes, e g. Fe3+OH–, Fe3+Cl–. The radicals produced by electron transfer excitation can be detected by their ability to initiate the polymerisation of vinyl compounds.
Studies in the Fundamental Processes of Textile Printing
Authors: MUNSHI . R H. , TURNER H. A.
Published: July 2010

An attempt has been made to reduce the complexity of the normal printing process on cellulosic fabrics in order that the characteristics of dyo transfer from the applied printing paste to tho cellulose might be studied quantitatively under standard conditions. Tho behaviour of a ntimber of purified direct cotton dyes has been studied. In many respects the transfer properties of the dye are similar to those which are obsorvod when the dye is applied from aqueous solution by a dyeing process, but important differences are found, especially in the proportion of dye transferred from the external phase to the cellulose.
A Note on the Formation of Polymers in Wool
Authors: FEABNLEY C. , SrBAKMAN J. B.
Published: July 2010

When wool fibres are impregnated with a dilute solution of ferrous ammonium sulphate and then treated with a mixture of hydrogen peroxide and methacrylamide in an atmosphere of nitrogen at 50°c, internal deposition of polymer takes place extremely slowly and reproducible results are difficult to obtain1. Those difficulties seem to be due to reaction between hydrogen peroxide and the monomer during uncontrolled times of standing before addition to the wool, because more rapid and reproducible deposition of polymer has now been realised simply by adding the solution of methacrylamide to the impregnated wool before the hydrogen peroxide.
The Spacing of Scales for Assessing the Effect on the Pattern in Fastness Testing
Authors: Mclaren K.
Published: July 2010

The spacing of the first grey scales considered for assessing loss in depth in fastness testing has been found to be unsatisfactory, a8 the resulting assessments do not reveal the small but important differenoes between patterns of good fastness; this defect is inherent in all equally spaced scales. It is shown that satisfactory results are obtained when the scales are spaced geometrically. Four geometric grey scales have been prepared and sent on behalf of the International Standards Organisation to the Fmtness Tests Committees of France, Germany, Switzerland, and the U.S.A. in the hope that agreement on the spacing may he achieved.
Control of Padding Processes by Radioactive Isotope Labelling
Authors: Hampson H. B. , Jones E. W.
Published: July 2010

Industrial uses of radioactive isotopes are briefly surveyed. Experiments show that radio‐isotope techniques may conveniently be employed to control the regularity of padded cloth, both across its width and throughout its length.
The Use of Hydrolysable Esters in the Control of Dyebaths
Authors: Hannay R. J. , Major W. H.
Published: July 2010

A study of the effects of initial pH, time, and temperature on the rate of hydrolysis of a number of esters in dyebaths is presented, and the results are discussed in relation to the selection of the most suitable ester to use under any particular set of conditions. It is shown that the hydrolysis of these esters is accelerated by raising the pH of the dyebath from 6 to approx. 10. In order to obtain the best results in the dyebath, an ester must be chosen the rate of hydrolysis of which is compatible with the time of dyeing under the particular pH conditions obtaining at the commencement of dyeing. The types of ester suitable for an initial pH of 6–7, 7–9, and 9–11 are indicated. This is followed by a survey of the experience gained in the use of these esters in wool dyeing on an industrial scale.
Proceedings of the Society The Basic Mechanisms of Dye Absorption during Pad‐dyeing
Authors: Mann H. B.
Published: July 2010

One‐day Symposium on Continuous Dyeing held by the Manchester Section at the Manchester College of Technology on 19th March 1954, Mr. J. Boulton in the chair

A study of the basic mechanisms of dye absorption during pad‐dyeing has shown that direct dyes are taken up by viscose rayon filament and staple fabrics in two waysndash(a) adsorbed at the surface of the individual filaments, and (b) in dye solution mechanically held within the fabric structure.

A differential absorption of dye and water has been clearly demonstrated. This must always be present in principle, although it may become overshadowed by substantive dyeing of the fibre at high padding temperatures or after prolonged immersion in the dyebath.
The Dyeing of Orlon and Orlon Mixtures
Authors: WALLS I. M. S.
Published: July 2010

The physical characteristics of the acrylic fibre Orlon are described briefly. Disperse dyes, basic dyes, acid dyes applied by the cuprous ion technique, and indigoid and thioindigoid vat dyes can be used to dye this fibre, and the dyeing and fastness properties of each class of dye are described fully. The selection of dyes for specific purposes is discussed, and some advice on practical dyeing and finishing procedure included. The dyeing of mixtures of Orlon with wool, nylon, and cellulosic fibres is described, and the paper concludes with some comments on the dyeing properties of analogous European acrylic fibres.
Dyeing Hydrophobic Fibres in Solutions of Solvents
Authors: Gokhale M. K. , Petees L. , Stevens C. B.
Published: July 2010

Data are presented concerning the rate of dyeing of cellulose triacetate loose staple fibre with 3% Duranol Red X3B 300 (C.I. Disperse Red 11, C.I. 62015) from aqueous solutions of η‐butanol or benzyl alcohol.

In water saturated with η‐butahol, more than 85% exhaustion is reached after 1 hr. at 80d̀c., 30 min. at 60d̀c., or 1 hr. at 40d̀c. After 30 min. in water saturated with benzyl alcohol, 68% of the dye present is fixed on the fibre at 40d̀c., 78% at 60d̀c., and 80% at 80d̀c. In general, with either solvent, the highest amount of dye fixation is obtained at about 60d̀c. At higher temperatures less solvent is needed and the time of dyeing can be reduced.

A method for dyeing Tricel (BrC) or Terylene (ICI) in fabric form is suggested.
Defective Colour Vision Comparison of a Colour Vision Test made from Dyed Wool Patterns with the Ishihara Test
Authors: Wain J. G.
Published: July 2010

The Wain Dichroic‐ladder test and the Ishihara test have been used to test 409 males. Of those tested, 9% were found to be defective by the Ishihara test. Statistical analysis of the results obtained from the Wain test showed that a further 3% of the observers could be regarded as having some form of colour defect. The new test was constructed so that it subtended an angle of 10° at the eye. Comparison of the observers' matches with the plots of the predicted matches suggests that the short‐wavelength receptors of the retina extend at least up to the boundary of the 10° field.
Practical Problems in Preparation and Dyeing of Cross‐wound Packages
Authors: Whittaker J.
Published: July 2010

Package dyeing is a relatively new but expanding method of advantageously producing dyed yarns for various end‐uses. Consideration is given to the principles governing the production and processing of suitable cross‐wound packages. Mention is made of some of the problems with which the package dyer is faced and recipes are outlined for overcoming them. Finally the advantages of high‐pressure drying are briefly discussed.
Some Difficulties in the Coloration of Plastics
Authors: Estevez J. M. J.
Published: July 2010

Some of the problems which confront those engaged in colouring plastics raw materials are reviewed. Some problems have their origin in manufacturing methods and others in the use to which the final article will be put. They are described, and methods for solving them are discussed. The limitations of mechanical aids to the solution of colouring problems are indicated and information is given on the most commonly used colorants.
Variation of Fading of Dyeings with Exposure
Authors: Jaeckel S. M. , Ward C. D.
Published: July 2010

The relationship between the spacing of blue standards and changes in grey‐scale contrast on doubling the duration of exposure to constant illumination is examined: experimental results1 suggest that the lower standards are spaced by a factor greater than 2. Fading‐rate relationships are derived from simple premises: they do not accord well with experimental results, and must be at least partially invalid, since the fading process is complex. Previously suggested relationships are only partly compatible one with another, but one fits recent results1 well. Changes in grey‐scale contrast on doubling exposures are derived from published data and from new work, for very different illumination conditions: four out of six cases show common features with results from exposures to fluorescent tubes1. Light‐fastness assessments based on Fugitometer exposures of Standards 2 and 3 are always likely to be misleading.
Some Applications of the Davidson and Hemmendinger Colorant Mixture Computer to Paints and Plastics
Authors: Tilleard D. L.
Published: July 2010

Test on colour formulation and correction of spectral matches to light‐coloured paints have given good results, but extension to the matching of deeper colours requires a closer consideration of the suitability of the function used and the exact interpretation of the computer indications. For gloss paints, a modified function, including the Saunderson correction for internal surface reflection, has been found suitable and with this function the computer can be satisfactorily applied to paints of medium depth, provided that they contain a substantial proportion of white base. At least sixty colours of BS 2660 “Colours for Building and Decorative Paints” could be matched satisfactorily by this means. Tests on a range of coloured plastic mouldings varying from nearly transparent to opaque gave satisfactory results only where opacity was high. Results are also reported on the colour matching of textiles.
The Identification of Metals in Dyed and Printed Protein and Cellulose Textiles
Authors: Burdett B. C.
Published: July 2010

With the increasing number of dye ranges being produced for the dyeing industry, not only has the presence of metals in dyed and printed textile materials become more common, but the number of metals encountered has increased. Consequently, new and sensitive tests are required for their identification, especially when they are present as a result of dyeing with 2: 1 dye‐metal complexes and in combinations. Methods are described for the identification of chromium, copper, cobalt, nickel, and iron alone, and, except for the latter, in combinations commonly encountered in dyeings and prints on wool, cotton, and viscose rayon.
Design Trends in Wallpaper and their Influence on Pigment Usage
Authors: GRIME R. E.
Published: July 2010

The two leading schools of fashion designers in Britain are the ‘Purists’, who are strictly utilitarian and original, and the ‘Romantics’, who tend to revive and re‐create designs from the past. The fluctuations in wallpaper design between these extremes are discussed and possible future developments are briefly mentioned. Before 1945 most wallpapers were printed with lakes made from the barium salts of acid dyes, supplemented by certain inorganic pigments. The subsequent demands for paler and brighter designs have led to the wider use of organic pigments. Fastness, chemical resistance, and toxicity problems are considered and economic aspects are indicated.