Studies on aromatic amino acid oxidase activity in ram spermatozoa: role of pyruvate as an antioxidant

Upreti, G.C.; Jensen, Kristoffer; Munday, Rex; Duganzich, D. M.; Vishwanath, R.; Smith, Johanna

doi:10.1016/s0378-4320(98)00082-7

Cited by 111 publications

(80 citation statements)

References 22 publications

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“…One group of oocytes was incubated in medium 199 supplemented with 5 mM pyruvate for 2 h, while the rest remained in control medium for the same period. Pyruvate was chosen for the experiment because it has been described as an effective physiological antioxidant for its ability to scavenge hydrogen peroxide (Upreti et al 1998).…”

Section: Determination Of Ros Production and Nuclear Stagementioning

confidence: 99%

Reactive oxygen species production and redox state in parthenogenetic and sperm-mediated bovine oocyte activation

et al. 2013

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The knowledge concerning redox and reactive oxygen species (ROS)-mediated regulation of early embryo development is scarce and remains controversial. The aim of this work was to determine ROS production and redox state during early in vitro embryo development in sperm-mediated and parthenogenetic activation of bovine oocytes. Sperm-mediated oocyte activation was carried out in IVF-modified synthetic oviductal fluid (mSOF) with frozen-thawed semen. Parthenogenetic activation was performed in TALP plus ionomycin and then in IVF-mSOF with 6-dimethylaminopurine plus cytochalasin B. Embryos were cultured in IVF-mSOF. ROS and redox state were determined at each 2-h interval (7-24 h from activation) by 2 0 ,7 0 -dichlorodihydrofluorescein diacetate and RedoxSensor Red CC-1 fluorochromes respectively. ROS levels and redox state differed between activated and non-activated oocytes (P!0.05 by ANOVA). In sperm-activated oocytes, an increase was observed between 15 and 19 h (P!0.05). Conversely, in parthenogenetically activated oocytes, we observed a decrease at 9 h (P!0.05). In sperm-activated oocytes, ROS fluctuated throughout the 24 h, presenting peaks around 7, 19, and 24 h (P!0.05), while in parthenogenetic activation, peaks were detected at 7, 11, and 17 h (P!0.05). In the present work, we found clear distinctive metabolic patterns between normal and parthenogenetic zygotes. Oxidative activity and ROS production are an integral part of bovine zygote behavior, and defining a temporal pattern of change may be linked with developmental competence.

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Section: Determination Of Ros Production and Nuclear Stagementioning

confidence: 99%

Reactive oxygen species production and redox state in parthenogenetic and sperm-mediated bovine oocyte activation

et al. 2013

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“…O processo de criopreservação gera aumento da produção de radicais livres e redução da capacidade antioxidante, provocando danos, inicialmente à membrana plasmática (Upreti et al, 1998), podendo se estender à cromatina (Thomson et al, 2009).…”

Section: Resultsunclassified

Efeito da utilização de diferentes diluidores para a produção in vitro de embriões bovinos

Prado

Koivisto

Carreira

et al. 2012

Arq. Bras. Med. Vet. Zootec.

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“…LAAO activity has also been observed in bull, ram, and stallion spermatozoa; however, the enzyme in human spermatozoa exhibits some notable differences with these species. In all other species analyzed, the enzyme has been found to exhibit an exclusive preference for aromatic amino acids (phenylalanine, tryptophan, and tyrosine; Tosic & Walton 1950, Shannon & Curson 1972, 1982, Upreti et al 1998. In human spermatozoa, tyrosine was not active as a substrate, but other nonaromatic L-amino acids (lysine, isoleucine, asparagine, and leucine) did exhibit a low level of activity (Fig.…”

Section: Discussionmentioning

confidence: 97%

“…This oxidase was found to have a particular propensity for the deamination of aromatic amino acids, with phenylalanine the preferred substrate (Tosic & Walton 1950). Subsequent studies have confirmed the presence of an LAAO in bull (Shannon & Curson 1972, 1982 and ram (Upreti et al 1998) spermatozoa with the potential to damage sperm function as a result of oxidative stress. The way in which exposure to hydrogen peroxide leads to a loss of sperm function has also been thoroughly investigated since the pioneering work of Tosic & Walton (1946), and shown to involve a number of pathological processes from the generation of cytotoxic aldehydes as a consequence of lipid peroxidation (Jones et al 1979, Aitken & Curry 2011, Aitken et al 2012 to the formation of potentially mutagenic base adducts in sperm DNA (De Iuliis et al 2009).…”

Section: Introductionmentioning

confidence: 91%

Human spermatozoa possess an IL4I1 l-amino acid oxidase with a potential role in sperm function

Houston¹,

Curry²,

Aitken³

2015

Reproduction

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Reactive oxygen species (ROS) are known to play an important role in the regulation of human sperm function. In this study, we demonstrate for the first time that human spermatozoa possess interleukin-induced gene 1 (IL4I1), an L-amino acid oxidase (LAAO) which is capable of generating ROS on exposure to aromatic amino acids in the presence of oxygen. The preferred substrates were found to be phenylalanine and tryptophan while the enzyme was located in the acrosomal region and midpiece of these cells. In contrast to equine and bovine spermatozoa, enzyme activity was lost as soon as the spermatozoa became non-viable. On a cell-to-cell basis human spermatozoa were also shown to generate lower levels of hydrogen peroxide than their equine counterparts on exposure to phenylalanine. Stimulation of LAAO activity resulted in the induction of several hallmarks of capacitation including tyrosine phosphorylation of the sperm flagellum and concomitant activation of phospho-SRC expression. In addition, stimulation of LAAO resulted in an increase in the levels of acrosomal exocytosis in both the presence and absence of progesterone stimulation, via mechanisms that could be significantly reversed by the presence of catalase. As is often the case with free radical-mediated phenomena, prolonged exposure of human spermatozoa to phenylalanine resulted in the stimulation of apoptosis as indicated by significant increases in mitochondrial superoxide generation and the activation of intracellular caspases. These results confirm the existence of an LAAO in human spermatozoa with a potential role in driving the redox regulation of sperm capacitation and acrosomal exocytosis.

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Studies on aromatic amino acid oxidase activity in ram spermatozoa: role of pyruvate as an antioxidant

Cited by 111 publications

References 22 publications

Reactive oxygen species production and redox state in parthenogenetic and sperm-mediated bovine oocyte activation

Reactive oxygen species production and redox state in parthenogenetic and sperm-mediated bovine oocyte activation

Efeito da utilização de diferentes diluidores para a produção in vitro de embriões bovinos

Human spermatozoa possess an IL4I1 l-amino acid oxidase with a potential role in sperm function

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