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141.
Phospholipid-Sensitive Ca2+ -Dependent Protein Kinase Preferentially Phosphorylates Serine-115 of Bovine Myelin Basic Protein 总被引:1,自引:0,他引:1
R. Scott Turner C.-H. Jen Chou† Gonzalo J. Mazzei Philip Dembure ‡ J. F. Kuo 《Journal of neurochemistry》1984,43(5):1257-1264
Phospholipid-sensitive Ca2+ -dependent protein kinase (PL-Ca-PK) and cyclic AMP-dependent protein kinase (A-PK) both preferentially phosphorylated serine residues of bovine myelin basic protein (MBP). Tryptic peptide maps of MBP phosphorylated by PL-Ca-PK or A-PK, however, revealed different phosphopeptides, suggesting a difference in the intramolecular substrate specificity for the two enzymes. Serine-115 of MBP, in the sequence (-Arg-Phe-Ser(115)-Trp-), was found to be a preferred and probably major phosphorylation site for PL-Ca-PK. Because serine-115 of bovine MBP corresponds to serine-113 of rabbit MBP, an in vivo phosphorylation site reported by Martenson et al. (1983), and PL-Ca-PK is present at a very high level in brain and myelin, it is suggested that the enzyme may be responsible for the in vivo phosphorylation of this and other sites in MBP. 相似文献
142.
143.
Studies were performed to explore the role of thyroid hormone and sex status on epidermal growth factor concentrations in the submandibular gland of a congenitally hypothyroid mouse model designated hyt/hyt. The animals were studied at 20, 30 and 40 days of postnatal age. The euthyroid animals were homozygous or heterozygous for the hypothyroid gene. The homozygous euthyroid animals displayed a pattern of submandibular gland epidermal growth factor concentrations similar to those previously described in other mouse species and showed the expected sex differences. The hypothyroid animals had measurable but very low submandibular gland epidermal growth factor concentrations without sexual dimorphism. Serum thyroxine concentrations in the heterozygotes were comparable to those in the homozygous euthyroid animals, yet the animals had a delayed increase in epidermal growth factor concentrations combined with a later expression of female-male differences. The timing of the sex differences in submandibular gland epidermal growth factor concentrations followed a pattern similar to that seen for the timing of the first litter in these three genetically distinct groups. This infers the timing of the onset of puberty and suggests a role of androgens in the changes seen in epidermal growth factor concentrations. We conclude that thyroid hormone and sex status in this mouse model influence the pattern and concentrations of submandibular gland epidermal growth factor concentrations. 相似文献
144.
Photosynthetic electron transport capacity was varied in vivo in sugar beets using iron deficiency, and its effects on the light modulation of ribulose bisphosphate carboxylase (RuBPCase) studied. Three treatment groups corresponding to decreasing amounts of thylakoids per leaf area were examined: iron sufficient (control), moderately iron-stressed, and severely iron-stressed. Reduction in electron transport capacity in vivo was correlated with a substantial decrease in the level of RuBPCase activation, even at saturating irradiances. These results indicate a direct relationship between RuBPCase activation and photosynthetic electron transport. In addition, our data suggest that the activation of RuBPCase could not solely account for the increases in the photosynthetic rate at high irradiances; RuBPCase reached maximal activation at irradiances well below light saturation for net photosynthesis.Abbreviations Chl
chlorophyll
- FeCN
ferricyanide
- FBPase
fructose 1,6-bisphosphatase
- RuBP
ribulose 1,5-bisphosphate
- RuBPCase
ribulose 1,5-bisphosphate carboxylase
- SBPase
sedoheptulose 1,7-bisphosphatase 相似文献
145.
Michael K. Smith Brenda J. Biggs Kenneth J. Scott 《Plant Cell, Tissue and Organ Culture》1986,6(3):221-228
A method is presented for the rapid in vitro propagation of cassava (Manihot esculenta Crantz). Nodal explants were induced to grow as multiple-shoot cultures on a medium containing 1.0 M 6-benzylamino purine (BAP), supplemented with 0.25 M -naphthaleneacetic acid (NAA). Nodes were removed from the shoots after three weeks of growth and subcultured on fresh culture medium. An average of 7.0 nodes were produced from each explanted node after three weeks in culture. Nodal explants were transferred to a medium containing 2.5 M indole-3-butyric acid (IBA) to improve root initiation on the developing plantlets. Plant establishment was possible upon transfer to soil. In vitro propagation offers enhanced rates of multiplication over more conventional methods of propagation. In addition, in vitro propagation facilitates the storage and international exchange of cassava germplasm. 相似文献
146.
Summary Length heterogeneity in the ribosomal repeat of Vicia faba is due to the presence of variable numbers of a 325 bp subrepetitive element within the nontranscribed spacer region. The distribution of size classes among 88 individuals within a population was investigated by blot-hybridization. We find that individual plants can exhibit more than 20 size classes and that hybridization patterns are highly diverse from individual to individual, more so than for any species so far investigated. In contrast, no such differences are observed in patterns for different tissues from a single plant or from parental to F1 generation. Some changes were observed in the F2 generation. We conclude that unequal recombination can give rise to the diversity that we observe for the V. faba rDNA repeats. 相似文献
147.
Scott L. Hooper Michael B. O'Neil Robert Wagner John Ewer Jorge Golowasch Eve Marder 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1986,159(2):227-240
Summary The muscles of the pyloric region of the stomach of the crab,Cancer borealis, are innervated by motorneurons found in the stomatogastric ganglion (STG). Electrophysiological recording and stimulating techniques were used to study the detailed pattern of innervation of the pyloric region muscles. Although there are two Pyloric Dilator (PD) motorneurons in lobsters, previous work reported four PD motorneurons in the crab STG (Dando et al. 1974; Hermann 1979a, b). We now find that only two of the crab PD neurons innervate muscles homologous to those innervated by the PD neurons in the lobster,Panulirus interrruptus. The remaining two PD neurons innervate muscles that are innervated by pyloric (PY) neurons inP. interruptus. The innervation patterns of the Lateral Pyloric (LP), Ventricular Dilator (VD), Inferior Cardiac (IC), and PY neurons were also determined and compared with those previously reported in lobsters. Responses of the muscles of the pyloric region to the neurotransmitters, acetylcholine (ACh) and glutamate, were determined by application of exogenous cholinergic agonists and glutamate. The effect of the cholinergic antagonist, curare, on the amplitude of the excitatory junctional potentials (EJPs) evoked by stimulation of the pyloric motor nerves was measured. These experiments suggest that the differences in innervation pattern of the pyloric muscles seen in crab and lobsters are also associated with a change in the neurotransmitter active on these muscles. Possible implications of these findings for phylogenetic relations of decapod crustaceans and for the evolution of neural circuits are discussed.Abbreviations
ACh
acetylcholine
-
Carb
carbamylcholine
-
cpv
muscles of the cardio-pyloric valve
-
cpv7n
nerve innervating muscle cpv7
-
cv
muscles of the ventral cardiac ossicles
-
cv1n
nerve innervating muscle cvl
-
cv2n
nerve innervating muscle cv2
-
EJP
excitatory junctional potential
-
IC
inferior cardiac neuron
-
IV
inferior ventricular neuron
-
IVN
inferior ventricular nerve
-
LP
lateral pyloric neuron
-
LPG
lateral posterior gastric neuron
-
lvn
lateral ventricular nerve
-
mvn
medial ventricular nerve
-
p
muscles of the pylorus
-
PD
pyloric dilator neuron
-
PD
in
intrinsic PD neuron
-
PD
ex
extrinsic PD neuron
-
pdn
pyloric dilator nerve
-
PY
pyloric neuron
-
pyn
pyloric nerve
-
STG
stomatogastric ganglion
-
VD
ventricular dilator neuron 相似文献
148.
Osbertia, a stoloniferous group confined to the montane regions of Mexico and adjacent Guatemala, was first proposed as a genus byGreene (1895), but most workers have retained the taxon as part ofHaplopappus. It is clearly closer toNoticastrum, Erigeron orHeterotheca than it is toHaplopappus sensu stricto. The present treatment recognizes two species, a widespread highly variableOsbertia stolonifera and a newly describedO. chihuahuana from northwestern Mexico. Distribution maps, distinguishing features, full synonymy and illustrations are presented. 相似文献
149.
Abstract Protein synthesis in Rhodomicrobium vannielii swarmer cells, incubated anaerobically in the dark, is dependent upon a rifampicin-sensitive step, indicating a dependence upon de novo RNA synthesis. In addition, toluene treatment has shown that the motile, non-differentiating swarmer cells have the capacity to initiate and sustain RNA synthesis. The major form of the DNA-dependent RNA polymerase responsible for this RNA synthesis has been identified. 相似文献
150.