Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spermatozoa of the shrew Suncus murinus, a mammal with abdominal testes, exhibit four unusual features: a giant acrosome; a dorsoventral asymmetry of their spermiation; a dorsoventral asymmetry of their head surface character; and also apparent surface maturity as they enter the epididymis. A Sertoli cell-periacrosomal cisternal complex envelops the giant acrosome during spermatid maturation. Spermiation is heraled by asymmetrical disorganization of the subplasmalemmal components of this complex and is completed by retraction of the Sertoli cell from the ventral and then the dorsal face of the spermatid head. This sequence or release is correlated with an asynchronous acquisition of negative surface charges on the spermatid head-demonstrable on glutaraldehyde-stabilized cells by the binding at pH 1.8 of positively charged colloidal particles of ferric oxide. Mature epididymal spermatozoa exhibit an asymmetry in the patterns of distribution of bound colloid over the dorsal vs. ventral surfaces of the sperm head, as well as regional differences between the tail midpiece and principal piece. Surface distributions of anionic residues and lectin (Con A)-binding sites characteristic of mature Suncus spermatozoa are demonstrable within the testis, unlike the situation in most nannals where distinct modifications of the sperm surface occur during epididymal passage.
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PMID:Asymmetry of spermiation and sperm surface charge patterns over the giant acrosome in the musk shrew Suncus murinus. 126 97

Pinellia ternata lectin (PTL), a protein exhibiting hemagglutination activity and carbohydrate binding specificity to mannan was purified from rhizome of Pinellia ternata. In this work the actions of PTL on artificial lipid bilayer were investigated by means of the two-compartment system of Mueller and Rudin. The lipid bilayer with resistance more than 10G omega was formed by a solution of lecithin and cholesterol (20 mg/ml and 5 mg/ml respectively) in N-decane. The electrical properties of the lipid bilayer were investigated in voltage clamp mode. Several minutes after the addition of PTL (2 micrograms/ml) in one compartment the channel-like noise as well as a decrease of the resistance of the bilayer were observed. These actions were inhibited by mannan significantly. The resistance increase of the bilayer with PTL-channels could be observed from 2G omega to control level (greater than or equal to 10 G omega) immediately after addition of 40 micrograms/ml mannan. The discrete conduction steps were recorded at low concentration of PTL and at low holding potential. The predominant unit conductance was 35pS in symmetric KCl solution of 100 mmol/L. The selectivity of PTL-channel was estimated from Goldman-Hodgkin-Katz equation by measurement of the reversal potential in an asymmetrical salt solution. The results showed that PTL-channels were cation selective.
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PMID:[Cation channels formed in lipid bilayer by Pinellia ternata lectin]. 137 36

In order to examine the synaptic input to dopaminergic neurones in the substantia nigra from GABAergic terminals and terminals that contain substance P, double and triple immunocytochemical studies were carried out at the light and electron microscopic levels in the rat. In a first series of experiments sections of the substantia nigra were incubated to reveal axon terminals containing either substance P or glutamate decarboxylase and then incubated to reveal dopaminergic neurones using tyrosine hydroxylase immunocytochemistry. Examination of this material in the light microscope revealed that many substance P- and glutamate decarboxylase-immunoreactive boutons were associated with the dopaminergic cells. In the electron microscope it was found that the perikarya and dendrites of the dopaminergic neurons received symmetrical synaptic input from terminals that displayed immunoreactivity for substance P or glutamate decarboxylase. A small proportion of the substance P-positive boutons formed asymmetrical synapses. In a second series of experiments sections of the substantia nigra were processed by the pre-embedding immunocytochemical technique for tyrosine hydroxylase and then the post-embedding immunogold technique for gamma-aminobutyric acid (GABA). Examination in the electron microscope revealed that the tyrosine hydroxylase-positive neurons received symmetrical synaptic input from many GABA-positive terminals. Quantitative analyses demonstrated that a minimum of 50-70% of all boutons afferent to the dopaminergic neurones display glutamate decarboxylase or GABA immunoreactivity. Triple immunocytochemical studies i.e. pre-embedding immunocytochemistry for tyrosine hydroxylase and substance P, combined with post-embedding immunogold staining for GABA, revealed that some of the substance P-immunoreactive boutons that were in contact with the dopaminergic neurones also displayed GABA immunoreactivity. In a third series of experiments the combination of anterograde transport of lectin-conjugated horseradish peroxidase or biocytin with post-embedding GABA immunocytochemistry demonstrated that at least one of the sources of GABA-containing terminals in the substantia nigra is the striatum. The results of the present study: (1) demonstrate that dopaminergic neurones in the substantia nigra receive symmetrical synaptic input from GABAergic and substance P-containing terminals, (2) show that a proportion of these terminals contain both substance P and GABA and (3) suggest that the major synaptic input to dopaminergic neurones is from GABAergic terminals and that a part of this innervation is derived from the striatum.
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PMID:The GABA and substance P input to dopaminergic neurones in the substantia nigra of the rat. 170 87

Phaseolus vulgaris leucoagglutinin (PHA-L) is a plant lectin that is anterogradely transported by neurons in the central nervous system. PHA-L is selectively taken up by cells at iontophoretic injection sites and, when immunohistochemically demonstrated, labels individual neurons completely, including their dendrites, axons, and terminal boutons. PHA-L is generally not taken up by fibers passing through the injection site and, because it produces a Golgi-like staining of even very fine axons over long distances, it is sometimes possible to light microscopically reconstruct individual neurons and their entire axon terminal arbors. When prepared for electron microscopy, the PHA-L-labeled terminals are densely and completely stained, allowing their synaptic relationships to be defined. These properties make PHA-L advantageous for studying the patterns of projection and the modes of termination of select groups of neurons in their target nuclei. We used PHA-L to study the extraretinal innervation of the cat's dorsal lateral geniculate nucleus, a thalamic visual center. Although much is known about the retinal contribution to geniculate synaptic circuitry, relatively little is known about other sources of innervation, even though these provide the majority of synaptic terminals in the nucleus (Guillery: Z. Zellforsch., 96:1-38, 39-48, 1969; Wilson et al.: Proc. R. Soc. Lond. [Biol.], 221:441-436, 1984). We used both light and electron microscopy to describe synaptic circuitry from three extraretinal sources of projections to the lateral geniculate nucleus: the visual cortex, the perigeniculate nucleus, and the parabrachial region of the brainstem. Cortical terminals labeled with PHA-L were small and formed asymmetrical synaptic contacts onto small-caliber dendrites of geniculate neurons. Perigeniculate terminals formed symmetrical synaptic contacts primarily onto small-caliber dendrites, but some synapses were also formed onto the proximal, retinorecipient portions of geniculate dendrites. Parabrachial terminals synaptically contacted the retinorecipient portions of dendritic appendages and shafts, small-caliber dendrites, and the specialized dendritic (F2) terminals of geniculate interneurons. The symmetry of the parabrachial synaptic contacts was variable and was related to the postsynaptic target. Contacts onto dendritic appendages were asymmetrical while those onto dendritic shafts and F2 terminals were symmetrical. Our data suggest that in unlabeled material these brainstem terminals would be difficult to distinguish from cortical or perigeniculate profiles. The positioning of the parabrachial input onto the retinorecipient portions of geniculate dendrites indicates that this projection is well situated to control primary retinal transmission through the nucleus, while the location of most cortical and perigeniculate innervations implicates them in secondary feedback interactions or other aspects of geniculate function.
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PMID:Phaseolus vulgaris leucoagglutinin (PHA-L): a neuroanatomical tracer for electron microscopic analysis of synaptic circuitry in the cat's dorsal lateral geniculate nucleus. 239 62

Choline acetyltransferase (ChAT) immunocytochemistry and lectin-conjugated horseradish peroxidase (WGA-HRP) histochemistry were combined at the electron microscopic level to examine the morphology of cholinergic terminals in the canine centrum medianum-parafascicular complex (CM-Pf) and to localize cholinergic terminals making synaptic contact with retrogradely labeled CM-Pf thalamostriatal projection neurons. Following WGA-HRP injections into the caudate nucleus, CM-Pf neurons were heavily labeled with WGA-HRP reaction product. Examination with the electron microscope revealed retrogradely labeled neurons characterized by a large nucleus with deep infoldings of the nuclear envelope. ChAT-positive terminals were observed arising from small-diameter nonmyelinated axonal profiles. These terminals varied in size from 0.5 to 1.4 micron in long diameter. The smaller terminals (0.5-0.7 micron) were seen most frequently and established symmetrical or slightly asymmetrical synaptic contacts with small dendritic profiles. The larger ChAT-positive terminals (1.0-1.4 micron) were less frequently observed, contained several mitochondria and small clusters of pleomorphic vesicles, and contacted large dendritic shafts and cell somata. Some of the postsynaptic targets of both smaller and larger ChAT-positive terminals were identified as belonging to retrogradely HRP-labeled thalamostriatal neurons. These observations indicate that at least some thalamostriatal neurons within the CM-Pf complex are innervated by cholinergic terminals which probably arise from ChAT-positive cell bodies located within the pontomesencephalic tegmentum, particularly within the nucleus tegmenti pedunculopontinus and the laterodorsal tegmental nucleus. These findings provide evidence for direct influence by cholinergic brainstem nuclei over activities of thalamostriatal neurons.
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PMID:Cholinergic innervation of canine thalamostriatal projection neurons: an ultrastructural study combining choline acetyltransferase immunocytochemistry and WGA-HRP retrograde labeling. 246 91

Ultrastructural behavior of fusiform vesicles with an asymmetrical unit membrane in the rat transitional epithelium was investigated by in situ injection of gold colloidal particles and gold-labeled Ricinus communis lectin, and by section staining with the lectin. These experiments suggest that the fusiform vesicles are not formed from the luminal cell membrane by contraction of the urinary bladder, and that old luminal cell membranes are removed via multivesicular bodies.
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PMID:Derivation and termination of fusiform vesicles in the transitional epithelium of the rat urinary bladder. 285 6

The fine structure of spinal and trigeminal projections to the parabrachial area (PB) of the rat was studied using either the anterograde transport of a lectin-peroxidase conjugate or the degeneration technique. Two morphologically different types of terminals were observed. Most labeled terminals contained round vesicles (R type) and formed asymmetrical synapses, usually with large dendrites. Others contained pleomorphic vesicles (P type) and usually made symmetrical contacts with large or medium-size dendrites. A double-labeling strategy was used, combining the retrograde labeling of PB neurons with lectin-peroxidase conjugate from the amygdala and the identification of degenerating terminals after lesions of spinal or trigeminal pathways. These experiments demonstrated that spinal and trigeminal terminals contact PB neurons that project to the central nucleus of the amygdala. The role of this spino(trigemino)-ponto-amygdalian pathway is discussed in relation to some aspects of pain.
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PMID:Spinal and trigeminal projections to the parabrachial nucleus in the rat: electron-microscopic evidence of a spino-ponto-amygdalian somatosensory pathway. 328 96

To understand how human corneal endothelium compensates for cell loss, nuclear DNA-cytofluorometry and cell morphometry were carried out on injured corneal endothelium. The examined corneas included two cases of keratoconus complicated with acute hydrops and one without acute hydrops, two cases of herpetic keratitis, one case of post-intracapsular cataract extraction (post-ICCE) and one case of luetic keratitis. The endothelial cell layer was separated from Descemet's membrane and double-stained with Rhodamine-labeled wheat germ agglutinin-lectin (WGA) and 4',6-diamidino-2-phenylindole dihydrochloride (DAPI). The area of each cell was measured with a color image analyser and compared with its cytofluorometric nuclear DNA content. The endothelium in apparently intact regions of the diseased corneas showed the same DNA-ploidy pattern and cell area as the physiological corneas. However, endothelial cells in injured regions had greater area, even in diploidy, than in presumably normal ones and showed a larger number of hyperploid cells ranging from 4C to 36C. Hyperploid cells consisted of many multinucleates and few polyploidies and had extremely large and bizarre cytoplasm. All injured corneas were accompanied by cells with numerous micronuclei. A few asymmetrical 4C-binucleates (with DNA values such as 1.3 plus 2.6C) appeared in the case of the post-ICCE. It is concluded that damage to human corneal endothelial cells in vivo results in cell enlargement with or without DNA synthesis. Those changes appear more severe in diseased corneas than in the situation of physiological aging which we have reported previously. In severe cases, micronuclei, polyploid cells and multinucleated giant cells are frequent, thereby suggesting a possible long-persistent metabolic impairment of the endothelium after severe damage to the cornea.
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PMID:Changes in nuclear DNA content and cell size of injured human corneal endothelium. 340 92

Vertebrate epithelial cells in monolayers are asymmetrical in that their apical and basal membranes differ in morphology and function. That this cell polarity depends on the presence of tight junctions can be demonstrated by labelling one surface of a cell monolayer in culture with fluorescent lectins and lipid probes, and subsequently observing whether the labels disperse to the opposite cell surfaces. Here we report on a differential distribution of binding sites for the lectin wheat germ agglutinin (WGA) on the cells of Drosophila melanogaster larval fat body, and show that the pattern is correlated with the structural association between the cell surfaces and their overlying basement membrane.
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PMID:Basement membrane polarizes lectin binding sites of Drosophila larval fat body cells. 640 96

Rat liver mannose-binding protein (MBP-C) is the smallest known member of the collectin family of animal lectins, many of which are involved in defence against microbial pathogens. It consists of an N-terminal collagen-like domain linked to C-terminal carbohydrate-recognition domains. MBP-C, overproduced in Chinese-hamster ovary cells, is post-translationally modified and processed in a manner similar to the native lectin. Analytical ultracentrifugation experiments indicate that MBP-C is trimeric, with a weight-averaged molecular mass of approx. 77 kDa. The rate of sedimentation of MBP-C and its mobility on gel filtration suggest a highly elongated molecule. Anomalous behaviour on gel filtration due to this extended conformation may explain previous suggestions that MBP-C forms a higher oligomer. The polypeptide chains of the MBP-C trimer are linked by disulphide bonds between two cysteine residues at the N-terminal junction of the collagen-like domain. Analysis of an N-terminal tryptic fragment reveals that the disulphide bonding in MBP-C is heterogeneous and asymmetrical. These results indicate that assembly of MBP-C oligomers probably proceeds in a C- to N-terminal direction: trimerization at the C-terminus is followed by assembly of the collagenous domain and finally formation of N-terminal disulphide bonds. The relatively simple organization of MBP-C provides a template for understanding larger, more complex collectins.
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PMID:Asymmetry adjacent to the collagen-like domain in rat liver mannose-binding protein. 923 Jan 18


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