The metabolic properties of spermatozoa from the epididymis of the tammar wallaby,Macropus eugenii

Murdoch, R. N.; Jones, Russell C.

doi:10.1002/(sici)1098-2795(199801)49:1<92::aid-mrd10>3.0.co;2-4

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…Another source of GlcNAc is free GlcNAc from the extracellular space. Extracellular free GlcNAc is rare, but it is present in seminal fluid, where it enters glycolysis and acts as an energy source for sperm [28]. Phosphorylation of GlcNAc by GlcNAc kinase is the initial step of this process and the enzyme is consequently highly expressed in the testes.…”

Section: Discussionmentioning

confidence: 99%

“…Because of the bifunctionality of UDP‐GlcNAc 2‐epimerase/ManNAc kinase, the key enzyme of Neu5Ac biosynthesis, ManNAc kinase activity is restricted to de novo biosynthesis of Neu5Ac [18]. Nevertheless, free ManNAc is derived by lysosomal degradation of Neu5Ac from oligosaccharides [28] and GlcNAc kinase may phosphorylate this substrate. For this reason a general role of GlcNAc kinase in the catabolic pathways of GlcNAc as well as of ManNAc is suggested.…”

Section: Discussionmentioning

confidence: 99%

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Molecular cloning and characterization of murine and human N‐acetylglucosamine kinase

Hinderlich¹,

Berger²,

Schwarzkopf

et al. 2000

European Journal of Biochemistry

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N-Acetylglucosamine is produced by the endogenous degradation of glycoconjugates and by the degradation of dietary glycoconjugates by glycosidases. It enters the pathways of aminosugar metabolism by the action of N-acetylglucosamine kinase. In this study we report the isolation and characterization of a cDNA clone encoding the murine enzyme. An open reading frame of 1029 base pairs encodes 343 amino acids with a predicted molecular mass of 37.3 kDa. The deduced amino-acid sequence contains matches of the sequences of eight peptides derived from tryptic cleavage of rat N-acetylglucosamine kinase. The recombinant murine enzyme was functionally expressed in Escherichia coli BL21 cells, where it displays N-acetylglucosamine kinase activity as well as N-acetylmannosamine kinase activity.The complete cDNA sequence of human N-acetylglucosamine kinase was derived from the nucleotide sequences of several expressed sequence tags. An open reading frame of 1032 base pairs encodes 344 amino acids and a protein with a predicted molecular mass of 37.4 kDa. Similarities between human and murine N-acetylglucosamine kinase were 86.6% on the nucleotide level and 91.6% on the amino-acid level. Amino-acid sequences of murine and human N-acetylglucosamine kinase show sequence similarities to other sugar kinases, and all five sequence motifs necessary for the binding of ATP by sugar kinases are present.Tissue distribution of murine N-acetylglucosamine kinase revealed an ubiquitous occurrence of the enzyme and a very high expression in testis. The size of the murine mRNA was 1.35 kb in all tissues investigated, with the exception of testis, where it was 1.45 kb mRNA of the murine enzyme was continuously expressed during mouse development. mRNA of the human enzyme was expressed in all investigated human tissues, as well as in cancer cell lines. In both the tissues and the cancer cell lines, the human mRNA was 1.35 kb in size.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Molecular cloning and characterization of murine and human N‐acetylglucosamine kinase

Hinderlich¹,

Berger²,

Schwarzkopf

et al. 2000

European Journal of Biochemistry

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“…Activation of sperm at ejaculation may alter metabolism to meet the potentially increased energy demands associated with motility (Garbers et al 1973a). In this context, sperm are able to utilize many different substrates as energy sources, including glucose, fructose, lactate, pyruvate, acetate, citrate, α-ketoglutarate, succinate, fumarate, malate, oxaloacetate, 8-hydroxybutyrate, glycerol, glycerol-3-phosphate, and N-acetyl-Dglucosamine White 1966, 1968;Garbers et al 1973aGarbers et al , 1973bHoskins 1973;Storey and Kayne 1977;Jones and Chantrill 1989;Ford and Rees 1990;Jones et al 1992;Armstrong et al 1994;Jones and Gillan 1996;Jones 1997;Murdoch and Jones 1998). Thus, it is widely believed that the metabolic activity and motility of sperm are closely linked.…”

Section: Introductionmentioning

confidence: 99%

Relationship between motility and oxygen consumption of sperm from the cauda epididymides of the rat

Rn¹,

Vl²,

Clulow³

et al. 1999

Reprod. Fertil. Dev.

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The oxygen consumption of rat sperm was low (2.7 microL O2 10(8) sperm(-1) h(-1)) in caudal epididymal semen (CES) when stimulation of motility was avoided. The addition of 1 microL of Krebs Ringer phosphate buffer (KRP) to 40 microL of CES (CES:KRP = 40:1) did not activate motility, but stimulated oxygen consumption 2-fold. Inclusion of 1-5 mM glucose, acetate, pyruvate or lactate in the KRP further stimulated respiration rate (up to 4.3-fold) without activating motility, but respiration was reduced when 2-deoxyglucose replaced energy substrates. Inclusion of dibutyryl cAMP (1 mM) activated sperm motility in all samples and stimulated oxygen consumption 2.9-fold. Dilution of CES at the ratio of CES:KRP = 40:1000 also activated sperm motility and stimulated respiration rate 2.9-fold. The combined effect of dibutyryl cAMP and glucose in stimulating respiration was greater than their individual effects. However, the response to cAMP or substrates was not altered by incubation in KRP containing either 0 or 0.5 mM Ca2+. It was concluded that the motility and metabolism of rat epididymal sperm are suppressed in vivo. Respiration can be stimulated by a small (1.025-fold) dilution and further stimulated by the inclusion of energy substrate, without activating motility. However, a larger dilution or inclusion of cAMP activated motility and simultaneously stimulated metabolism, with exogenous substrate being required to stimulate respiration to the maximum rate. This suggests that prior to activation, the rate of oxygen consumption and sperm motility are not coupled.

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“…A study by Hinderlich et al [57] showed higher transcript expression of this gene in the mouse testis, suggesting an important function of this gene in male reproductive npg functions. Murdoch and Jones [58] also mention that N-acetyl glucosamine, the substrate for this enzyme, acts as an energy source for spermatozoa only after being phosphorylated, thereby demonstrating the importance of N-acetyl-glucosamine kinase for sperm function. Decreased expression of this protein during epididymal maturation could mean a reduced preference for N-acetyl glucosamine as an energy substrate.…”

Section: Discussionmentioning

confidence: 99%

Glucose-regulated protein precursor (GRP78) and tumor rejection antigen (GP96) are unique to hamster caput epididymal spermatozoa

Kameshwari

Bhande²,

Sundaram³

et al. 2010

Asian J Androl

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The immotile testicular mammalian spermatozoon gets transformed into a motile spermatozoon during 'epididymal maturation'. During this process, the spermatozoa transit from the caput to the cauda epididymis and undergo a number of distinct morphological, biophysical and biochemical changes, including changes in protein composition and protein modifications, which may be relevant to the acquisition of motility potential. The present proteome-based study of the hamster epididymal spermatozoa of caput and cauda led to the identification of 113 proteins spots using Matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS) analysis. Comparison of these 113 protein spots indicated that 30 protein spots (corresponding to 20 proteins) were significantly changed in intensity. Five proteins were increased and eleven were decreased in intensity in the cauda epididymal spermatozoa. In addition, two proteins, glucose-regulated protein precursor (GRP78) and tumor rejection antigen (GP96), were unique to the caput epididymal spermatozoa, while one protein, fibrinogen-like protein 1, was unique to cauda epididymal spermatozoa. A few of the five proteins, which increased in intensity, were related to sperm metabolism and ATP production during epididymal maturation. The changes in intensity of a few proteins such as ERp57, GRP78, GP96, Hsp60, Hsp70, and dihydrolipoamide S-acetyltransferase were validated by immunoblotting. The present study provides a global picture of the changes in protein composition occurring during hamster sperm epididymal maturation, besides being the first ever report on the proteome of hamster spermatozoa.

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The metabolic properties of spermatozoa from the epididymis of the tammar wallaby,Macropus eugenii

Cited by 8 publications

References 21 publications

Molecular cloning and characterization of murine and human N‐acetylglucosamine kinase

Molecular cloning and characterization of murine and human N‐acetylglucosamine kinase

Relationship between motility and oxygen consumption of sperm from the cauda epididymides of the rat

Glucose-regulated protein precursor (GRP78) and tumor rejection antigen (GP96) are unique to hamster caput epididymal spermatozoa

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