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1.
2.
Randall J. Gee 《Journal of morphology》1987,191(2):193-204
The nerve pathways in the praesoma are described for a member of the class Eoacanthocephala for the first time. Eleven nerves, five paired and one single, are traced from the cerebral ganglion to their associations with the musculature of the body wall, neck sense organs, and the musculature of the proboscis wall and the invertor muscles of the proboscis. The structure and location of the stutzzelle and series of nerve endings in the hypodermis of the body wall and at the apex of the proboscis are described. 相似文献
3.
Two isoforms of dihydroxyacetone phosphate reductase were present in Dunaliella tertiolecta. The major form was located in the chloroplast and the minor form in the cytosol. The chloroplastic reductase eluted first from a DEAE cellulose column followed immediately by the cytosolic form. Both forms were unstable and cold labile. Addition of 5 millimolar dithiothreitol helped to stabilize the enzymes. The cytosolic isoform of DHAP reductase was detected only if the cells were in an active log phase of growth. Then its activity was 20 to 30% of the total reductase activity. When cell cultures entered late log phase of growth the activity of the cytosolic form of the enzyme disappeared, but the chloroplastic form remained. The cytosolic DHAP reductase from Dunaliella has some properties similar to the cytosolic isoform from spinach leaves. Detergents inhibited both enzymes. However, neither form of the algal dihydroxyacetone phosphate reductase was stimulated by fructose 2,6-bisphosphate. In Dunaliella the properties of the chloroplastic form were those expected for glycerol production for osmoregulation, whereas the cytosolic form, like the reductases in leaves, is more likely involved in glycerol phosphate formation for lipid synthesis. 相似文献
4.
A monoclonal antibody to bovine brain inositol monophosphatase. Immunoaffinity purification of the brain and kidney enzymes and evidence for their structural identity. 总被引:1,自引:1,他引:0
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A monoclonal IgG2b(K) antibody, G-2A4, has been generated against bovine brain myo-inositol monophosphatase (EC 3.1.3.25). The identity of the antigen recognized by the antibody was established by using e.l.i.s.a. and Western blotting procedures, and by immunoprecipitation of enzyme activity from crude brain supernatant. In addition, the hydrolysis of Ins1P by crude brain extract was inhibited by up to 83% by the pure antibody. Under identical conditions, the hydrolysis of Ins(1,4)P2 was unaffected. An immunoadsorbent column containing monoclonal antibody G-2A4 covalently attached to CNBr-activated Sepharose 4B has been used for rapid purification of the brain enzyme. Elution conditions have been optimized to allow isolation of the enzyme in high yield (54%) with full retention of column-binding capacity. The enzyme was electrophoretically homogeneous, Mr 30,000 and of higher specific activity than that purified conventionally. Chromatography of the pure enzyme on high resolution ion-exchange columns revealed some charge heterogeneity, possibly indicative of some type of post-translational modification. The immunoadsorbent column has also been used to purify the bovine kidney cortex enzyme to homogeneity. Partial proteolytic fragmentation patterns of the brain and kidney enzymes using endoprotease glu-C were identical, suggesting that they are almost certainly products of the same gene. 相似文献
5.
Classification and ordination of macroinvertebrate assemblages to predict stream acidity in upland Wales 总被引:2,自引:2,他引:0
Macroinvertebrates were collected from riffles at 104 sites in upland Wales during April and July 1984. Species assemblages were ordinated by DECORANA, classified by TWINSPAN and related to stream chemistry and other environmental factors using correlation and multiple discriminant analysis. DECORANA axis 1 was most strongly correlated with pH and aluminium concentration whilst axis 2 correlated with stream gradient and flow. Four TWINSPAN site groups established in each season were also principally related to pH and aluminium concentration, and reflected overall taxon-richness; differences between groups were most apparent during spring, when catchment forest cover and taxon-richness were also related. A dichotomous key based on indicator species was established for each season with the coleopteran Hydraena gracilis Germar and the Ephemeroptera, including Baetis rhodani Pictet, important indicators at Level 1. We propose that these indicator systems may be used for the rapid detection and assessment of acid waters throughout Wales, and that the methodology is applicable generally. 相似文献
6.
Omega-hydroxylation of prostaglandin E1 in the isolated perfused lungs of pregnant rabbits 总被引:1,自引:0,他引:1
M T Leithauser D L Roerig S M Winquist A Gee R T Okita B S Masters 《Prostaglandins》1988,36(6):819-833
Cytochrome P450PG omega is induced in the rabbit lung in a gestational age-dependent manner and hydroxylates certain eicosanoids at their terminal, or omega (omega), carbon. This enzyme has been isolated from microsomal fractions and its activity has been characterized (Williams, D.E., et al., J. Biol. Chem. 259; 14600-14608, 1984). The experiments presented here examine the omega-hydroxylation activity of the intact lung during presentation of an eicosanoid substrate, prostaglandin E1 (PGE1), to the lung vasculature. Isolated, perfused lungs from three pregnant and four nonpregnant rabbits were injected with [3H]-PGE1. One-second fractions were collected from the perfusion effluent and were analyzed for metabolism of PGE1. Lungs isolated from pregnant rabbits metabolized PGE1 mainly to two polar derivatives, 20-hydroxy-PGE1 and 13,14-dihydro-15-keto-20-hydroxy-PGE1, whereas lungs from nonpregnant rabbits yielded mainly a relatively nonpolar metabolite, 13,14-dihydro-15-keto-PGE1. These metabolites were identified by coelution with standards that were generated enzymatically in vitro and whose structures were confirmed by gas chromatography/mass spectrometry (GC/MS). 相似文献
7.
F Cerasoli M H Gee Y Ishihara K H Albertine M V Tahamont J E Gottlieb S P Peters 《Tissue & cell》1988,20(4):505-517
The role played by neutrophil oxidative responses in host defense and injury is an area of active investigation. In order to study neutrophil responses in vitro, methods are required for cell purification, enumeration, and quantification of activation responses, which mimic the in vivo situation as closely as possible. In this communication (and its companion paper, Albertine et al., 1988) improved methods for all of these tasks are described and applied to investigate neutrophil structure-function relationships in vitro and in vivo. Human neutrophils were purified by using a series of platelet-poor plasma-Percoll gradients (51, 62, 76 and 80% in Percoll). This modification of previously published procedures results in consistently successful neutrophil purification and has allowed us to purify neutrophils from bronchoalveolar lavage fluid as well as blood. Activation of human and sheep neutrophils (superoxide anion production) was quantitated by the reduction of ferricytochrome c using a microtiter plate reader to measure the increase in absorbance at 550 nm from adherent neutrophils. Adherence of neutrophils was quantitated by measurement of LDH in cells lysed with Triton X-100 using a new method which uses readily available commercial reagents and can quantitate the LDH content of as few as 5000 neutrophils (or the LDH released from 5% of 100,000 neutrophils). Assay conditions for superoxide anion were optimized, limitations both in assay design and instruments used to measure OD were explored and enumerated, and these methods were used to quantitate sheep and human neutrophil activation responses. Using methods described in Albertine et al. (1988) for fixing neutrophils in microtiter wells after assay of their functional capacity, we have studied the same cells functionally and morphologically. We have used these techniques to study blood and alveolar neutrophils from a patient with acute respiratory failure. His alveolar neutrophils displayed 67% of the activation response as peripheral neutrophils (4.31 +/- 0.12 nmol superoxide released per 250,000 neutrophils at 60 min vs. 6.38 +/- 0.18 in blood, P less than 0.01) and structural changes which suggested previous activation in vivo. These studies demonstrate that similar morphological changes are observed in neutrophils activated with phorbol myristate acetate in vitro, as are observed in cells which have been activated by pathophysiologic processes in vivo. 相似文献
8.
Identification and characterization of a pregnane steroid recognition site that is functionally coupled to an expressed GABAA receptor 总被引:2,自引:0,他引:2
Conclusion Based on the pharmacological and biochemical evidence to date, especially that derived from the recombinantly expressed receptor studies, the suggestion that a novel GBRC-linked steroid recognition site exists becomes a cogent argument. The high affinity of the steroid site for certain naturally occurring metabolites of progesterone and glucocorticoids favors a physiologic role for these steroids in the regulation of brain excitability. Clearly, investigations of such a regulatory role is warranted. If present, it provides an important example of endocrine control of a major inhibitory neurotransmitter in the CNS. Moreover, as we gain a greater understanding of the molecular organization of the GBRC, the putative steroid site provides a novel target for the rational design of therapeutic agents for the treatment of anxiety, epilepsy, and insomnia.Special issue dedicated to Dr. Eugene Roberts. 相似文献
9.
Proteins of the kidney microvillar membrane. The 130 kDa protein in pig kidney, recognized by monoclonal antibody GK5C1, is an ectoenzyme with aminopeptidase activity. 总被引:6,自引:3,他引:3
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The hybridoma GK5C1, secreting a monoclonal IgG1 antibody, was generated after immunizing a mouse with pig kidney microvillar membranes. An immunoradiometric assay showed that only kidney and intestine contained detectable amounts of the antigen recognized by the antibody, the highest concentration being observed in the ileum. Immunocytochemistry confirmed this observation and revealed that the antigen was associated with renal and intestinal brush borders. By 'Western' blotting, the antigen in kidney microvilli was shown to be a 130 kDa polypeptide. Papain treatment of the membrane before blotting converted the antigen to a 125 kDa polypeptide, no longer associated with membrane. Immunoaffinity chromatography of detergent-solubilized kidney membranes yielded a pure 130 kDa protein. When one purification was monitored by the immunoradiometric assay, the yield was 3.5% and the purification factor was 1000-fold. The antigen constituted about 0.8% of the microvillar membrane protein. The protein could be reconstituted into liposomes, where electron microscopy revealed an asymmetric orientation, similar to that of ectoenzymes in this membrane. The stalk length was about 3 nm. In electron micrographs the purified protein appeared to be dimeric. A search for enzymic activity was rewarded when L-leucyl-L-tryptophan was observed to be hydrolysed. Failure to hydrolyse N-blocked peptides and the ability to release the N-terminal residue from extended peptides, including Leu-Trp-Leu and Leu-Trp-Met-Arg, showed that the activity was that of an aminopeptidase. The enzyme was maximally active at pH 7.5 and irreversibly inactivated outside the range pH 6-10. This activity could not be attributed to trace contamination with aminopeptidase N. The best substrates so far identified for the 130 kDa protein were those with tryptophan in the P1', position. This protein is a new microvillar enzyme and it is proposed that it be called aminopeptidase W. 相似文献
10.
Michael Younga Adrian P. Gee Michael D. P. Boyleb Michael J. P. Lawman Kathy L. Mungera 《Molecular and cellular biochemistry》1985,66(1):65-69
Summary High molecular weight mouse nerve growth factor(H M W-NGF), in addition to its effects on certain neural elements, is also chemotactic for human polymorphonuclear leukocytes. One of the subunits of H M W-NGF is a protease of the serine family and its active site contains a serine residue and a closely-neighboring histidine residue that are both essential for proteolysis. Elimination of enzyme activity by irreversibly blocking the single serine has no effect on leukotaxis, but blocking the histidine abolishes leukotaxis. These results suggest the possibility that part of the proteolytic active site of this enzyme may have evolved to perform more than one, completely different, biologic function — proteolysis as well as nonproteolytically mediated chemotaxis.Abbreviations HMW-NGF
mouse submandibular gland nerve growth factor, purified as in Ref. 1
- DFP
diisopropyl-phosphofluoridate
- DIP-NGF
diisopropyl-phosphoryl-NGF; phe-pro-arg-CH2C1, D-phenylalanyl-L-propyl-L-argininyl chloromethyl ketone; TLCK, N-p-tosyl-L-lysine chloromethyl ketone
- TAME
N-p-tosyl L-arginine methyl ester
- EDTA
ethylenediamine tetraacetic acid 相似文献