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  • 1
    Electronic Resource
    Electronic Resource
    Electron-microscopic localisation of thiol and disulphide groups by direct monomaleimido-nanogold labelling in the spermatozoa of a marsupial, the tammar wallaby (Macropus eugenii) (1995)
    Springer
    Cell & tissue research 282 (1995), S. 291-296 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Spermatozoa ; Acrosome ; Thiols ; Disulphides ; Electron microscopy ; Monomaleimido nanogold ; Macropus eugenii (Marsupialia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. This study utilised a commercially available monomaleimido-nanogold reagent to directly label cellular thiol groups (SH) of marsupial (tammar wallaby) spermatozoa before and after reduction of disulphides (S-S) with mercaptoethylamine hydrochloride (MEA). The sperm surface, mitochondrial membranes, axoneme and tail fibres were all labelled with gold particles before MEA treatment and the label intensity was increased after S-S reduction. The acrosomal membranes and matrix of spermatozoa contained no detectable SH prior to MEA treatment. However, after moderate MEA treatment (1 mg/ml) gold label was associated with the acrosomal membrane and invaginated acrosomal membrane within the acrosomal matrix. After exposure to 5 and 10 mg/ml MEA, gold particles heavily labelled the acrosomal matrix. Thus, the acrosomal membranes and matrix of tammar wallaby spermatozoa both contain S-S cross-linked structures, and this may contribute to the unusual stability of the marsupial acrosome. Under all treatment conditions the nucleus remained unlabelled. This is consistent with early studies which indicated that cysteine was absent from the nuclear protamines. The study also demonstrated that monomaleimido-nanogold can be used to resolve SH- and S-S-rich cellular structures directly, in addition to its use to label antibodies and Fab fragments for immunochemical localisation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050480
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  • 2
    Electronic Resource
    Electronic Resource
    Electron-microscopic localisation of thiol and disulphide groups by direct monomaleimido-nanogold labelling in the spermatozoa of a marsupial, the tammar wallaby (Macropus eugenii) (1995)
    Springer
    Cell & tissue research 282 (1995), S. 291-296 
    Details
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Acrosome ; Thiols ; Disulphides ; Electron microscopy ; Monomaleimido nanogold ; Macropus eugenii (Marsupialia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study utilised a commercially available monomaleimido-nanogold reagent to directly label cellular thiol groups (SH) of marsupial (tammar wallaby) spermatozoa before and after reduction of disulphides (S-S) with mercaptoethylamine hydrochloride (MEA). The sperm surface, mitochondrial membranes, axoneme and tail fibres were all labelled with gold particles before MEA treatment and the label intensity was increased after S-S reduction. The acrosomal membranes and matrix of spermatozoa contained no detectable SH prior to MEA treatment. However, after moderate MEA treatment (1 mg/ml) gold label was associated with the acrosomal membrane and invaginated acrosomal membrane within the acrosomal matrix. After exposure to 5 and 10 mg/ml MEA, gold particles heavily labelled the acrosomal matrix. Thus, the acrosomal membranes and matrix of tammar wallaby spermatozoa both contain S-S cross-linked structures, and this may contribute to the unusual stability of the marsupial acrosome. Under all treatment conditions the nucleus remained unlabelled. This is consistent with early studies which indicated that cysteine was absent from the nuclear protamines. The study also demonstrated that monomaleimido-nanogold can be used to resolve SH- and S-S-rich cellular structures directly, in addition to its use to label antibodies and Fab fragments for immunochemical localisation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319119
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  • 3
    Electronic Resource
    Electronic Resource
    Respiration rates and sugar utilization by marsupial spermatozoa (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 111-116 
    Details
    ISSN: 0148-7280
    Keywords: sperm ; respiration ; substrates ; marsupial ; possum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This paper reports the first metabolic study of marsupial spermatozoa. The oxidative metabolism of the spermatozoa of the Australian brush-tailed possum (Trichosurus vulpecula) was examined using a micro Warburg system. Semen was collected by electro-ejaculation and washed twice in Ca2+ free Krebs-Ringer-phosphate buffer containing antibiotics (KRPA). Washed spermatozoa suspended in fresh KRPA, were then incubated for 3 hours at 37° C in the presence and absence of added substrates (4 mM). The exogenous substrates tested were N-acetylglucosamine, glucosamine, and glucose. Small quantities of radioactively labeled [14C] substrates were included in the incubation media to allow measurement of substrate oxidation.Although the respiratory rate varied considerably between semen pools (replicate experiments), the relationship between total oxygen consumption (measured manometrically), and oxygen consumption accounted for by exogenous substrate utilization (calcuated from radioactivity recovered in the respiratory CO2) was remarkably consistent. Oxidation of exogenous substrate accounted for 49-54% of the oxygen consumption, depending on the substrate used. There was, however, no evidence that addition of these substrates stimulated the respiratory rate over that found when no substrate was added. Lactate formation accounted for the greater part of exogenous substrate consumed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010204
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  • 4
    Electronic Resource
    Electronic Resource
    Lysophosphatidylcholine disrupts the acrosome of tammar wallaby (macropus eugenii) spermatozoa (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 35 (1993), S. 277-284 
    Details
    ISSN: 1040-452X
    Keywords: Acrosome ; Marsupial ; Tammar wallaby ; Lysophosphatidylcholine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The acrosomal status of wallaby spermatozoa was evaluated by light and electron microscopy after incubation in 1-100 μM lysophosphatidylcholine (LPC) for up to 120 min. Treatment with 1 and 10 μM LPC for 120 min did not lead to acrosomal loss, or detectable alteration to the acrosome, as detected by Bryan's staining and light microscopy. Incubation with 25 μM LPC had little effect on acrosomal loss, however statistically significant changes (P 〈 0.05) in the acrosomal matrix (altered) were detected after 10-min incubation by light microscopy. Around 50% of acrosomes were altered after 20-min incubation in 50 μM LPC (P 〈 0.001), and 40% of spermatozoa had lost their acrosome after 60-min incubation (P 〈 0.001). Treatment with 75 and 100 μM LPC led to rapid acrosomal loss from around 50% of spermatozoa within 10 min (P 〈 0.001), and by 60 min acrosomal loss was 70-80%. LPC, like the diacylglycerol DiC8 (1,2-di-octanoyl-sn-glycerol), is thus an effective agent to induce loss of the relatively stable wallaby sperm acrosome, and it also induces changes within the acrosomal matrix.Ultrastructure of the LPC-treated spermatozoa revealed that the plasma membrane and the acrosomal membranes were disrupted in a manner similar to that seen after detergent treatment (Triton X-100). There was no evidence of point fusion between the plasma membrane overlying the acrosome and the outer acrosomal membrane. The plasma membrane was the first structure to disappear from the spermatozoa. The acrosomal membranes and matrix showed increasing disruption with time and LPC concentration. Wallaby spermatozoa incubated with LPC at concentrations that induced significant acrosomal loss also underwent a rapid decline in motility that suggested that acrosomal loss may be due to cell damage, rather than a physiological AR. This study concluded that LPC-induced acrosomal loss from tammar wallaby spermatozoa is due to its action as a natural detergent and not as a phosphoinositide pathway intermediate. The study further demonstrates the unusual stability of the marsupial acrosomal membranes. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080350310
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  • 5
    Electronic Resource
    Electronic Resource
    Fluorescent localization of thiols and disulfides in marsupial spermatozoa by bromobimane labelling (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 318-325 
    Details
    ISSN: 1040-452X
    Keywords: Tammar wallaby ; Brushtail possum ; Acrosome stability ; Disulfides ; Bromobimane labelling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The acrosome of marsupial spermatozoa is a robust structure which, unlike its placental counterpart, resists disruption by detergent or freeze/thawing and does not undergo a calcium ionophore induced acrosome reaction. In this study specific fluorescent thiol labels, bromobimanes, were used to detect reactive thiols in the intact marsupial spermatozoon and examine whether disulfides play a role in the stability of the acrosome. Ejaculated brushtail possum (Trichosurus vulpecula) and tammar wallaby (Macropus eugenii) spermatozoa were washed by swim up and incubated with or without dithiothreitol (DTT) in order to reduce disulfides to reactive thiols. Spermatozoa were then washed by centrifugation and treated with monobromobimane (mBBr), a membranepermeable bromobimane, or with monobromotrimethylammoniobimane (qBBr), a membrane-impermeable bromobimane. Labelled spermatozoa were examined by fluorescence microscopy and sperm proteins (whole sperm proteins and basic nuclear proteins) were analysed by gel electrophoresis. The membrane-permeable agent mBBr lightly labelled the perimeter of the acrosome of non-DTT-treated possum and wallaby spermatozoa, indicating the presence of peri-acrosomal thiol groups. After reduction of sperm disulfides by DTT, mBBr labelled the entire acrosome of both species. The membrane-impermeable agent qBBr did not label any part of the acrosome in non-DTT or DTT-treated wallaby or possum spermatozoa. Thiols and disulfides are thus associated with the marsupial acrosome. They are not found on the overlying plasma membrane but are either in the acrosomal membranes and/or matrix. The sperm midpiece and tail were labelled by mBBr, with increased fluorescence observed in DTT-treated spermatozoa. The nucleus was not labelled in non-DTT or DTT-treated spermatozoa. Electrophoretic analysis confirmed the microscopic observations: Basic nuclear protein (protamines) lacked thiols or disulfide groups. Based on these findings, the stability of the marsupial acrosome may be due in part to disulfide stabilization of the acrosomal membranes and/or acrosomal matrix. In common with placental mammals, thiol and disulfide containing proteins appear to play a role in the stability of sperm tail structures. It was confirmed that the fragile marsupial sperm nucleus lacked thiols and disulfides. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370311
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  • 6
    Electronic Resource
    Electronic Resource
    In vitro maturation of oocytes from a marsupial, the tammar wallaby (Macropus eugenii) (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 34 (1993), S. 329-336 
    Details
    ISSN: 1040-452X
    Keywords: Macropus eugenii ; Maturation ; Oocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This study examined the competence of oocytes from the tammar wallaby, Macropus eugeniio mature in vitro. Oocytes were collected from follicles 〉1 mm diameter 24 h after pregnant mare serum gonadotrophin (PMSG) treatment and incubated in Eagle's minimum essential medium supplemented with 10% fetal calf serum, at 35°C in 5% CO2 in air for 24, 36, or 48 h. Oocytes were incubated either granulosa cell-intact or granulosa cell-free or in the presence of 10 IU ml-1 PMSG or 10 μg ml-1 porcine luteinizing hormone (LH) + 10 μg ml-1 porcine follicle stimulating hormone (FSH). The ability of oocytes recovered from small (〈1.5-mm-diameter) and large (≥1.5-mm-diameter) follicles to mature in vitro was also examined. The nuclear status of oocytes was assessed using the DNA-specific dye Hoechst 33342. Initially, all oocytes examined contained a germinal vesicle. After 24 h of culture, 60% of oocytes had progressed to metaphase I or anaphase I. After 36 h, approximately 20% of oocytes possessed metaphase II chromosomes, and 20% of oocytes were at metaphase I or anaphase I. At the completion of the 48 h culture period, 40% of oocytes had completed maturation to the metaphase II stage. In vitro oocyte maturation after 48 h was not affected by the presence of granulosa cells, PMSG, or LH and FSH. More oocytes from large follicles (55%) completed maturation by 48 h than from small follicles (20%). Approximately 50% of oocytes remained at the GV stage at all times under all conditions. Marsupial oocytes thus undergo spontaneous nuclear maturation once removed from the follicular environment, suggesting a basically similar control system to that in placental mammals. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080340314
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  • 7
    Electronic Resource
    Electronic Resource
    Glycosidase and cumulus dispersal activities of acrosomal extracts from opossum (marsupial) and rabbit (eutherian) spermatozoa (1981)
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 507-514 
    Details
    ISSN: 0148-7280
    Keywords: acrosome ; glycosidase ; cumulus oophorus ; marsupial ; opossum ; rabbit ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Opossum and rabbit sperm sonicates dispersed the mouse cumulus oophorus in vitro at the same rate on a per sperm basis, despite much higher activities of the glycosidic acrosomal enzymes N-acetylhexosaminidase (350 ×) and arylsulphatase (40 ×) in the opossum preparation. Activities of another glycosidase, hyaluronidase, and the protease acrosin where similar in sperm extracts from both species. However, specific inhibitors of N-acetylhexosaminidase (iodoacetate) and arylsulphatase (SO42-, PO43-) markedly reduced the rate of cumulus dispersal by rabbit sperm sonicates. These findings suggest that, while hyaluronidase action probably represents the rate-limiting (slow) step, several glycosidases act together to disperse the cumulus and in the passage of the fertilizing spermatozoon through it in eutherian mammals. The likely role of these acrosomal enzymes in the marsupial, where the ovulated oocytes lack a cumulus oophorus, is more uncertain.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120040604
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  • 8
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    Electron-microscopic localisation of thiol and disulphide groups by direct monomaleimido-nanogold labelling in the spermatozoa of a marsupial, the tammar wallaby ( Macropus eugenii ) (1995)
    Springer
    Details
    Publication Date: 1995-10-01
    Print ISSN: 0302-766X
    Electronic ISSN: 1432-0878
    Topics: Biology , Medicine
    Published by Springer
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  • 9
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    Electron-microscopic localisation of thiol and disulphide groups by direct monomaleimido-nanogold labelling in the spermatozoa of a marsupial, the tammar wallaby (Macropus eugenii) (1995)
    Springer
    Details
    Publication Date: 1995-11-01
    Print ISSN: 0302-766X
    Electronic ISSN: 1432-0878
    Topics: Biology , Medicine
    Published by Springer
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  • 10
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    Mammalian hair as an accumulative bioindicator of metal bioavailability in Australian terrestrial environments (2009)
    Elsevier
    Details
    Publication Date: 2009-05-01
    Print ISSN: 0048-9697
    Electronic ISSN: 1879-1026
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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