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1.
Summary The horseradish-peroxidase (HRP) technique was used to visualize the cell bodies of axons projecting to the goldfish pituitary. Following intravenous injections of HRP, HRP reaction products were observed in axons of the rostral pars distalis, proximal pars distalis, neurointermediate lobe, pituitary stalk and in axons coursing from the pituitary into the hypothalamus. HRP-labelled cells in the brain were localized in two regions only — the nucleus preopticus (NPO) pars magnocellularis and pars parvocellularis, and the nucleus lateralis tuberis (NLT) of the hypothalamus. These observations suggest that the NPO and NLT are the source of the neurosecretory innervation of the goldfish pituitary. 相似文献
2.
Geoffrey Fryer 《Hydrobiologia》1993,250(2):119-125
On the island of Rhum (Inner Hebrides: Western Scotland) several taxonomically diverse species of small crustaceans live in water that is more acidic and of lower ionic content than that in which they have ever been found in Yorkshire (England). Physiological difficulties appear to be experienced by these species in Yorkshire in waters that would evidently be suitable in Rhum. This may be due to the presence of heavy metals and other substances derived from atmospheric pollution, of which Rhum is largely free, that act synergistically with other stressful factors. Evidence from other areas is in agreement with this suggestion.The few species that are specialised for life in highly acidic water can frequent more acidic conditions in Yorkshire than any encountered on Rhum. Nevertheless certain species that are common in the Northern Pennines have not been found in the Southern Pennines where pollution has been most intense. One species that is common in the Northern, but has not been found in the Southern Pennines, formerly occurred there as shown by abundant remains in the peat. 相似文献
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Identification of three muscarinic receptor subtypes in rat lung using binding studies with selective antagonists 总被引:6,自引:0,他引:6
Heterogeneity of the muscarinic receptor population in the rat central and peripheral lung was found in competition binding experiments against [3H]quinuclidinyl benzilate [( 3H]QNB) using the selective antagonists pirenzepine, AF-DX 116 and hexahydrosiladifenidol (HHSiD). Pirenzepine displaced [3H]QNB with low affinity from preparations of central airways indicating the absence of M1 receptors in the trachea and bronchi. Muscarinic receptors in the central airways are comprised of both M2 and M3 receptors since AF-DX 116, an M2-selective antagonist, bound with high affinity to 70% of the available sites while HHSiD, an M3-selective antagonist bound with high affinity to the remaining binding sites. In the peripheral lung, pirenzepine bound with high affinity to 14% of the receptor population, AF-DX 116 bound with high affinity to 79% of the binding sites while HHSiD bound with high affinity to 18% of the binding sites. The presence of M1 receptors in the peripheral airways but not in the central airways was confirmed using [3H]telenzepine, an M1 receptor ligand. [3H]Telenzepine showed specific saturable binding to 8% of [3H]QNB labeled binding sites in homogenates of rat peripheral lung, while there was no detectable specific binding in homogenates of rat trachea or heart. The results presented here demonstrate that there are three muscarinic receptor subtypes in rat lungs, and that the distribution of the different subtypes varies within the lungs. Throughout the airways, the dominant muscarinic receptor subtype is M2. In the trachea and bronchi the remaining receptors are M3, while in the peripheral lungs, the remaining receptors are both M1 and M3. 相似文献
5.
Enzymological and mutational analysis of a complex primary hyperoxaluria type 1 phenotype involving alanine:Glyoxylate aminotransferase peroxisome-to-mitochondrion mistargeting and intraperoxisomal aggregation 总被引:6,自引:1,他引:5 下载免费PDF全文
C. J. Danpure P. E. Purdue P. Fryer S. Griffiths J. Allsop M. J. Lumb K. M. Guttridge P. R. Jennings J. I. Scheinman S. M. Mauer N. O. Davidson 《American journal of human genetics》1993,53(2):417-432
Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive disease caused by a deficiency of the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). Three unrelated PH1 patients, who possess a novel complex phenotype, are described. At the enzymological level, this phenotype is characterized by a complete, or nearly complete, absence of AGT catalytic activity and reduced AGT immunoreactivity. Unlike normal individuals in whom the AGT is confined to the peroxisomal matrix, the immunoreactive AGT in these three patients was distributed approximately equally between the peroxisomes and mitochondria. The peroxisomal AGT appeared to be aggregated into amorphous core-like structures in which no other peroxisomal enzymes could be identified. Mutational analysis of the AGT gene showed that two of the three patients were compound heterozygotes for two previously unrecognized point mutations which caused Gly41→Arg and Phe152→Iso amino acid substitutions. The third patient was shown to be a compound heterozygote for the Gly41→Arg mutation and a previously recognized Gly170→Arg mutation. All three patients were homozygous for the Pro11→Leu polymorphism that had been found previously with a high allelic frequency in normal populations. It is suggested that the Phe152→Iso and Gly170→Arg substitutions, which are only eighteen residues apart and located in the same highly conserved internal region of 58 amino acids, might be involved in the inhibition of peroxisomal targeting and/or import of AGT and, in combination with the Pro11→Leu polymorphism, be responsible for its aberrant mitochondrial compartmentalization. On the other hand, the Gly41→Arg substitution, either in combination with the Pro11→Leu polymorphism or by itself, is predicted to be responsible for the intraperoxisomal aggregation of the AGT protein. 相似文献
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Geoffrey Fryer 《Hydrobiologia》1995,307(1-3):57-68
The distinctness of the Anomopoda and the polyphyletic nature of the so-called Cladocera are emphasized.An attempt is made to reconstruct the ancestral anomopod, which probably lived in Palaeozoic times. This task is facilitated by the availability of detailed information on extant forms, which includes functional as well as purely morphological considerations and enables us to understand the means whereby complex mechanisms were transformed during evolution. Comparative studies on the ecology and habits of extant forms also throw light on the probable way of life of the ancestral anomopod.Adaptive radiation within the Anomopoda is briefly surveyed and an outline of the suggested phylogeny of the order is indicated.Institute of Environmental and Biological Sciences, University of Lancaster 相似文献
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Accumulation of heavy metals in unicellular algae 总被引:2,自引:0,他引:2
10.
M. J. Fryer 《Redox report : communications in free radical research》2013,18(2):159-161
A critical novel function for the antioxidant vitamin E (α-tocopherol) may be its involvement in the control of apoptosis in which it acts as a ‘gate keeper’ in the regulation of membrane lipid peroxidation. The biochemical and biophysical antioxidant properties of the molecule are discussed together with recent evidence for its involvement in a possible model of the apoptotic mechanism. The original observation that led to the discovery of vitamin E (foetal resorption in pregnant rats fed on tocopherol-deficient diets) is considered as an unrecognised example of apoptosis. 相似文献