Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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Certain ocular proteins have been found to be chemically modified by exposure to near-UV light (320-390 nm) in the presence of tryptophan. Colored and fluorescent tryptophan photoproducts bind firmly to proteins, thereby altering their physico-chemical properties. The question of whether such a reaction would inhibit the catalytic action of catalase is herein raised. When solutions of bovine liver catalase were re-incubated up to 24 hr under near-UV with preirradiated tryptophan and dialyzed, most of the ability of the enzyme to decompose H2O2 was lost. Similar results occurred for catalase activities of bovine cornea and lens epithelia. The enzyme protein exhibited altered UV absorption and fluorescence spectra and increased electrophoretic mobility after binding photoproducts, Near-UV light photoproducts of tryptophan are thus capable of deactivating crystalline and tissue catalase.
Mol Cell Biochem 1976 Jun 15
PMID:Inactivation of catalase by near ultraviolet light and tryptophan photoproducts. 94 May 47

Keratan sulfate was isolated from bovine cornea. The water vapor sorption isotherms were obtained on both sodium and calcium salts of keratan sulfate at different temperatures. Deuterated water sorption isotherms were obtained on sodium keratan sulfates. The infrared spectra of the keratan-sulfate was monitored as a function of water and D2O uptake. The results are discussed in terms of an open polymer matrix that exists in the solid state of keratan sulfate.
Mol Cell Biochem 1975 Feb 28
PMID:Water vapor sorption of keratan sulfate. 112 84

Pili confer the initial ability of Neisseria gonorrhoeae to bind to epithelial cells. Pilin (PilE), the major pilus subunit, and a minor protein termed PilC, reportedly essential for pilus biogenesis, undergo intra-strain phase and structural variation. We demonstrate here that at least two different adherence properties are associated with the gonococcal pili: one is specific for erythrocytes, which is virtually unaffected by PilE variation, and another is specific for epithelial cells, and is modulated in response to the variation of PilE. Based on this finding, mutants of a recA- strain were selected that had lost the ability to bind to human cornea epithelial cells (A-) but retained the ability to form pili (P+) and to agglutinate human erythrocytes (H+). The adherence-negative mutants failed to produce detectable levels of PilC1 or PilC2 proteins, representing piIC phase variants generated in the absence of RecA. The A- pilC phase variants were indistinguishable from their A+ parents and spontaneous A+ revertants with regard to the amount of PilE produced and its electrophoretic mobility, the degrees of piliation and haemagglutination, and the pilE nucleotide sequence. These data demonstrate a central role for PilC in pilus-mediated adherence of N. gonorrhoeae to human epithelial cells and further indicate that neither PilC1 nor PilC2 is obligatory for the assembly of gonococcal pili.
Mol Microbiol 1992 Nov
PMID:Interaction of two variable proteins (PilE and PilC) required for pilus-mediated adherence of Neisseria gonorrhoeae to human epithelial cells. 136 47

A prominent circadian rhythm was found in the labelling indices (LI) of the peripheral rat corneal epithelium and of the adjacent conjunctival epithelium, while almost no diurnal variation was found in the central area. Application of a double labelling technique indicated that there are rhythmic pulses of high and low influx of cells into the S phase and similar pulses of efflux of cells from the S phase. Results of the study indicate that there are different cohorts of cycling cells all over the rat corneal epithelium. Cells belonging to a rapidly proliferating cohort are observed in the peripheral cornea. There is a gradual reduction in the fraction of labelled DNA-synthesizing cells towards the centre. The considerably lower fraction of cells taking up tritiated thymidine (3H)TdR in the central cornea may be due to a higher fraction of basal cells having reached higher levels of differentiation. This may result in a shift from the salvage to the de novo pathway. The slowly proliferating cohort seems to have a prolonged S phase duration and displays practically no diurnal variation in the LI. The DNA-synthesizing cells belonging to this latter cohort probably use the salvage pathway for DNA synthesis resulting in uptake of (3H)TdR all over the cornea. The LI is thus not a reliable indicator of cell proliferation in the corneal epithelium, due both to the heterogeneity of the cell proliferation, and in particular due to the lack of labelling of the centrally located DNA-synthesizing cells. To what extent these properties may also be present in other proliferating tissues with different levels of differentiations, may be questioned.
Virchows Arch B Cell Pathol Incl Mol Pathol 1990
PMID:Circadian variations in the DNA synthesis of the rat corneal epithelium. A study using double labelling with tritiated thymidine. 197 Jun 85

A stathmokinetic method was used to study the diurnal variation in the mitotic rate (MR) of the rat corneal epithelium, and in the adjacent conjunctival epithelium. A prominent circadian variation in cell proliferation was observed in both epithelia, both showing almost the same pattern, which may indicate that both tissues are submitted to the same regulatory mechanisms. The average rate of cell renewal during a 24 h period indicated a mean cell renewal time of 12.3 days. This is longer than previously assumed. The MR declined toward the central cornea. Based on the above observations and the known centripetal migration of cells in the corneal epithelium, we have developed a mathematical model showing isomorphism with the renewal of the corneal epithelium.
Virchows Arch B Cell Pathol Incl Mol Pathol 1989
PMID:Circadian variation in the mitotic rate of the rat corneal epithelium. Cell divisions and migration are analyzed by a mathematical model. 257 18

Low-temperature dehydration and embedding techniques have been used to preserve the transverse structure of corneal collagen fibrils for study using electron microscopy. The diameters of the fibrils, which were found to be about 45% larger than those determined previously for specimens prepared for electron microscopy using conventional dehydration and embedding, lie close to those deduced from low-angle X-ray diffraction patterns from untreated hydrated specimens of cornea.
J Ultrastruct Mol Struct Res
PMID:Preservation of corneal collagen fibril structure using low-temperature procedures for electron microscopy. 311 34

The ocular pharmacokinetics of bendazac were studied in rabbits, following intravenous administration of bendazac lysine. The compound and its 5-hydroxyderivative were determined in different eye compartments and plasma by radioassay, using [14C]bendazac, and HPLC. The highest concentrations were found in the iris and in descending order in the ciliary body, retina, cornea, tears, aqueous humor, vitreous, and lens. The time course of concentrations in the plasma, aqueous and vitreous humor, ciliary body, and retina showed kinetics described by the exponential equation y = aebx with a half-life of 2.47, 4.56, 3.59, and 3.22 hr, respectively; in the lens the half-life was 17.77 hr.
Exp Mol Pathol 1985 Dec
PMID:Investigations on the ocular pharmacokinetics of bendazac in rabbits. 406 7

The reoxygenation technique originally used by Ferguson and Richardson (1978) for the revival and the ultrastructural improvement of tracheal and bronchial mucosae obtained post-mortem, has been applied to lung parenchyma, skin, liver, cerebellar cortex and skeletal muscle. The results show that the ultrastructural changes caused by post-mortem anoxia lasting 2 1/2-5 h were at least partially reversible in the alveolar epithelium and in the epidermis after 3 h reoxygenation in O2-saturated Krebs-Henseleit physiological solution at 37 degrees C. In contrast, reoxygenation was without any positive effect on anoxic changes in liver parenchyma, cerebellar cortex and skeletal muscle. The oxygen content of the immediate environment and temperature decrease are supposed to be the main protective factors influencing the reversibility of anoxia and thus affecting the results of reoxygenation. It might be expected that other superficially localized and air-exposed tissues (the nasal, paranasal, pharyngeal, laryngeal and oral mucosae, conjunctiva and cornea) could be revived or ultrastructurally improved by the reoxygenation technique.
Virchows Arch B Cell Pathol Incl Mol Pathol 1981
PMID:Reoxygenation of anoxic human tissues. An application for electron microscopy and its limits. 611 53

Hemidesmosomes of normal mouse corneal epithelium observed in tangential thin sections, occupy 14% of the basal plasma membrane. They consist of linear chains of densities with an orientation that is not random with respect to the radial axis of the cornea, tending to parallel it. During the repair of a small epithelial defect, cells of the corneal epithelium peripheral to the defect show chains of hemidesmosomes arranged parallel to the direction of migration of the epithelial sheet. This is parallel to the radius, like the orientation of the normal chains. Cells of the area that was denuded of epithelium, and is being resurfaced, show no hemidesmosomes. During repair of a large defect of the corneal epithelium hemidesmosomes are present on the cells covering the denuded area but they are small, few in number compared to the normal, and many are not arranged in chains. These small hemidesmosomes appear to be points of attachment of very fine basal filaments, possibly actin.
Virchows Arch B Cell Pathol Incl Mol Pathol 1982
PMID:Hemidesmosomes of normal and regenerating mouse corneal epithelium. 613 76

Cytokeratins are a family of polypeptides that form the intermediate-sized filament characteristic of epithelial cells. The cytoskeletons of different types of epithelial cells have been reported to possess specific combinations of the members of this protein family. Therefore, we have sought to examine the correspondence between such differential protein expression and the expression of cytokeratin genes at the nucleic acid level. A library of recombinant plasmids carrying cDNA sequences synthesized from bovine epidermal mRNAs was constructed. Clones of about 10(3) base-pairs coding for all the major epidermal keratins of molecular weights of 50,000, 54,000, 59,000, 60,000 and 68,000 were identified by means of hybridization-selection, followed by one and two-dimensional gel electrophoresis of products of translation in vitro. Under stringent conditions, each of these clones hybridizes specifically with its corresponding mRNA and does not show significant cross-hybridization with mRNAs coding for the other keratins, including those belonging to the same subfamily. Using these clones in RNA blot hybridization analysis, we have studied the expression of keratin genes in diverse bovine epithelial tissues (muzzle epidermis, cornea, esophagus, bladder urothelium, liver) and cultured cell lines from kidney (MDBK) and mammary gland (BMGE + H, BMGE -H). In each case we have found a correlation between the respective keratin polypeptides and the corresponding mRNAs. Whereas mRNA coding for keratins Ia and VIb have been found only in epidermis, genes coding for other epidermal keratins are expressed also in certain non-epidermal epithelia and in cells of the BMGE + H line. In contrast, epidermal keratin mRNA sequences have not been detected in liver or bladder tissue, nor in cultured kidney cells (MDBK) or mammary gland cells of the BMGE - H line, which all express a set of cytokeratin polypeptides entirely different from those of epidermis. In all cases, only one mRNA size species has been found, suggesting that in different cell types the same mRNA species is synthesized from the same keratin gene. We conclude that the mechanisms controlling the cell type-specific synthesis of the diverse keratin genes act at a pre-translational level.
J Mol Biol 1984 Jun 15
PMID:Cell type-specific expression of bovine keratin genes as demonstrated by the use of complementary DNA clones. 620 61


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