Article

Ultrastructural immunolocalization of lysyl oxidase in vascular connective tissue

The Journal of Cell Biology (Impact Factor: 9.83). 10/1986; 103(3):1121-8.
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ABSTRACT

The localization of lysyl oxidase was examined in calf and rat aortic connective tissue at the ultrastructural level using polyclonal chicken anti-lysyl oxidase and gold conjugated rabbit anti-chicken immunoglobulin G to identify immunoreactive sites. Electron microscopy of calf aortic specimens revealed discrete gold deposits at the interface between extracellular bundles of amorphous elastin and the microfibrils circumferentially surrounding these bundles. The antibody did not react with microfibrils which were distant from the interface with elastin. There was negligible deposition of gold within the bundles of amorphous elastin and those few deposits seen at these sites appeared to be associated with strands of microfibrils. Lysyl oxidase was similarly localized in newborn rat aorta at the interface between microfibrils and nascent elastin fibers. Gold deposits were not seen in association with extracellular collagen fibers even after collagen-associated proteoglycans had been degraded by chondroitinase ABC. However, the antibody did recognize collagen-bound lysyl oxidase in collagen fibers prepared from purified collagen to which the enzyme had been added in vitro. No reaction product was seen if the anti-lysyl oxidase was preadsorbed with purified lysyl oxidase illustrating the specificity of the antibody probe. The present results are consistent with a model of elastogenesis predicting the radial growth of the elastin fiber by the deposition and crosslinking of tropoelastin units at the fiber-microfibril interface.

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    • "The above results could be related to a connective tissue cross-linking mechanism during ice storage of the jumbo squid. This mechanism likely results from the lysyl oxidase activity, which crosslinks the collagen in the muscle by forming Pyr and increases the shear force of the fibrils (Kagan et al., 1986; Smith-Mungo & Kagan, 1998; Torres-Arreola et al., 2012). However, the increase in shear force Figure 1 Changes in texture of mantle from jumbo squid (Dosidicus gigas) during ice storage. "
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    ABSTRACT: Collagen fibres, stabilised by lysyl oxidase (LOX), play an important role in jumbo squid because they are responsible for the union between various cells; therefore, a close interdependence between their functions and muscle firmness during ice storage has been suggested. In this study, the relationship between LOX activity, pyridinoline (Pyr) content and muscle texture (SF) during ice storage of jumbo squid mantle was evaluated. LOX activity was confirmed within the range of 4.1–7.1 × 10−3 U g−1 of protein, leading to an increase in Pyr content, detected in the range of 0.85–1.32 mmol mol−1 of collagen after 5–20 days. The SF of the muscle became harder during the ice storage time, increasing from 21.08 to 37.95 N. It was therefore possible to establish the relationship between LOX activity, collagen cross-links (Pyr content) and texture patterns during ice storage of jumbo squid muscle, which increased after 20 days.
    Full-text · Article · Sep 2015 · International Journal of Food Science & Technology
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    • "The above results could be related to a connective tissue cross-linking mechanism during ice storage of the jumbo squid. This mechanism likely results from the lysyl oxidase activity, which crosslinks the collagen in the muscle by forming Pyr and increases the shear force of the fibrils (Kagan et al., 1986; Smith-Mungo & Kagan, 1998; Torres-Arreola et al., 2012). However, the increase in shear force Figure 1 Changes in texture of mantle from jumbo squid (Dosidicus gigas) during ice storage. "

    Full-text · Article · Jan 2015 · International Journal of Food Science & Technology
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    • "Besides collagen, elastin fibrils are also present, particularly in the midposterior part of the human peripheral cornea (Alexander and Garner 1983; Kamma-Lorger et al. 2010). Under physiological conditions the final enzymatic step required for collagen and elastin cross-linking in the corneal stroma is catalyzed by lysyl oxidase (LOX) (Mizobe et al. 2008; Kagan et al. 1986). Recently, artificial corneal collagen cross-linking method has become regularly used for the KC stabilization. "
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    ABSTRACT: Keratoconus (KC) is an eye disease characterized by the progressive thinning and protrusion of the cornea, which results in the loss of visual acuity. This disorder remains poorly understood, although recent studies indicate the involvement of genetic and environmental factors. Recently, we have found that the distribution of the cross-linking enzyme lysyl oxidase (LOX) is markedly decreased in about 63 % of keratoconic specimens. Similarly, LOX activity is significantly reduced by 38 % compared to control tissue. Nearly 70 systemic disorders have been reported in association with KC, most of them affecting the extracellular matrix. In this review we attempted to ascertain whether any KC-associated diseases exhibit signs that may reflect LOX impairment. We hypothesized that very similar changes in the extracellular matrix, particularly at the level of collagen metabolism, including LOX impairment in mitral leaflets, may reflect an association between KC and mitral valve prolapse. Moreover, this putative association is supported by the high frequency of Down syndrome in both diseases. Among other disorders that have been found to coincide with KC, we did not find any in which the LOX enzyme may be directly or indirectly impaired. On the other hand, in cases where KC is present along with other connective tissue disorders (Marfan syndrome, Ehlers-Danlos syndrome and others), KC may not arise as a localized manifestation, but rather may be induced as the result of a more complex connective tissue disorder.
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