https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52876 Wed 28 Feb 2024 11:01:07 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:53095 Wed 27 Mar 2024 12:12:14 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:53340 Wed 22 Nov 2023 10:18:49 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48935 Wed 19 Apr 2023 14:47:54 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24338 Wed 17 Nov 2021 16:29:37 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:30545 Wed 15 Dec 2021 16:09:36 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54802 Wed 13 Mar 2024 11:42:00 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29909 P < 0.001) were found between ALDH expression and various motility parameters of stallion spermatozoa including the percentage of progressive (r = 0.79) and rapidly motile (r = 0.79) spermatozoa, whereas repeated measurements over 24 h revealed highly significant correlations among progressive motility loss, 4HNE accumulation, and ALDH expression (P ≤ 0.001). ALDH inhibition resulted in a spontaneous increase in 4HNE levels in viable cells (21.1 ± 5.8% vs. 42.6 ± 5.2%; P ≤ 0.05) and a corresponding decrease in total motility (41.7 ± 6.2% vs. 6.4 ± 2.6%; P ≤ 0.001) and progressive motility (17.0 ± 4.1% vs. 0.7 ± 0.4%; P ≤ 0.001) of stallion spermatozoa over 24 h. Similarly, inhibition of ALDH in 4HNE-challenged spermatozoa significantly reduced total motility over 4 h (35.4 ± 9.7% vs. 15.3 ± 5.1%, respectively; P ≤ 0.05). This study contributes valuable information about the role of the ALDH enzymes in the maintenance of stallion sperm functionality, with potential diagnostic and in vitro applications for assisted reproductive technologies.]]> Wed 11 Apr 2018 16:45:10 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24546 In vitro sperm storage is a necessary part of many artificial insemination or in vitro fertilization regimes for many species, including the human and the horse. In many situations spermatozoa are chilled to temperatures between 4 and 10°C for the purpose of restricting the metabolic rate during storage, in turn, reducing the depletion of ATP and the production of detrimental by-products such as reactive oxygen species (ROS). Another result of lowering the temperature is that spermatozoa may be "cold shocked" due to lipid membrane phase separation, resulting in reduced fertility. To overcome this, a method of sperm storage must be developed that will preclude the need to chill spermatozoa. If a thermally induced restriction-of-metabolic-rate strategy is not employed, ATP production must be supported while ameliorating the deleterious effects of ROS. To achieve this end, an understanding of the nature of energy production by the spermatozoa of the species of interest is essential. Human spermatozoa depend predominantly on glycolytic ATP production, producing significantly less ROS than oxidative phosphorylation, with the more efficient pathway predominantly employed by stallion spermatozoa. This review provides an overview of the implications of sperm metabolism for in vitro sperm storage, with a focus on ambient temperature storage in the stallion.]]> Wed 11 Apr 2018 14:27:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:30037 Wed 11 Apr 2018 13:40:38 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26316 Wed 11 Apr 2018 09:24:47 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:34663 Wed 10 Apr 2019 13:35:43 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40175 in vivo, or in vitro as a result of sperm storage, purification and processing. Following a brief description of the production, homeostasis and functions of ROS in mammalian sperm function, this review paper will focus on describing the predominant sources of ROS in the ejaculate, the effects of ROS on a cellular and molecular level, and the actions of ROS from the whole animal perspective. There is highlighting of some studies, which have revealed the mechanisms for these observations, along with some strategies to ameliorate or prevent the instigation of the oxidative stress cascade before irreversible damage to spermatozoa occurs.]]> Wed 06 Jul 2022 12:28:36 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43493 Tue 20 Sep 2022 15:35:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48336 Tue 14 Mar 2023 17:16:12 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54790 Tue 12 Mar 2024 14:35:02 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:53638 Tue 12 Dec 2023 16:36:04 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:32666 capacitation in order to attain the competence to recognize the egg and then engage in a complex cascade of cell–cell interactions in order to achieve union of the gametes at fertilization. This process involves extensive remodelling of the sperm plasma membrane as well as the induction of hyperactivated motility and, as such, is a highly energy-dependent process. The process of spermatogenesis requires extensive remodelling of a conventional spherical cell to become one of the most highly specialized and morphologically differentiated cells in the body. During this transformation, the DNA in the sperm nucleus reaches the physical limits of compaction to achieve a quasicrystalline state. This extreme compaction requires the removal or resorption of most of the cytoplasm, at the same time removing the majority of the organelles (such as the endoplasmic reticulum, ribosomes and Golgi apparatus) that are intimately involved in the regulation of metabolism in somatic cells. The result of this extensive remodelling is that spermatozoa are left translationally and transcriptionally silent, as well as relatively depleted of intracellular enzymes and energy reserves such as fat droplets, yolk granules and glycogen. For this reason, spermatozoa are heavily dependent on their immediate extracellular environment for the energy substrates that drive metabolism, as well as a variety of specialized enzymatic activities that would normally be conducted intracellularly. For example, in somatic cells, the array of enzymes and low-molecular-mass scavengers involved in mediating protection against oxidative stress is housed intracellularly, largely within the cytoplasmic space. Spermatozoa, on the other hand, largely depend upon the epididymal and seminal plasmas to provide the richest and most diverse combination of antioxidants in the body, including several that are unique to the male reproductive tract. In much the same way that economies trade using a currency rather than a barter system, biological systems have all evolved their own unique ‘currencies’ for the exchange of energy.The most important of these currencies is adenosine 5’-triphosphate (ATP), which provides the metabolic energy to drive activities in all living cells.]]> Tue 10 Jul 2018 11:47:12 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:55850 Tue 02 Jul 2024 11:47:42 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:42127 P < 0.001). Furthermore, the deleterious effects of GSH depletion using menadione and 1,3 dimethoxy 1,4, naphtoquinone (DMNQ) were able to be prevented by the addition of cysteine, but no other antioxidant. Pre-incubation with cysteine prevented menadione and DMNQ induced damage to sperm membranes after 1 h (P < 0.001; P < 0.05) and after 3 h of incubation (P < 0.001, P < 0.05). Pre-incubation with cysteine ameliorated both the menadione- and DMNQ-induced increase in 4-hydroxynonenal (P < 0.001). As cysteine is a precursor of GSH, we hypothesized that stallion spermatozoa are able to synthesize this tripeptide using exogenous cysteine. To test this hypothesis, we investigated the presence of two enzymes required to synthesize GSH (GSH and GCLC) and using western blotting and immunocytochemistry we detected both enzymes in stallion spermatozoa. The inhibition of GCLC reduced the recovery of GSH by addition of cysteine after depletion, suggesting that stallion spermatozoa may use exogenous cysteine to regulate GSH. Other findings supporting this hypothesis were changes in sperm functionality after BSO treatment and changes in GSH and GSSG validated using HPLC-MS, showing that BSO prevented the increase in GSH in the presence of cysteine, although important stallion to stallion variability occurred and suggested differences in expression of glutamate cysteine ligase. Mean concentration of GSH in stallion spermatozoa was 8.2 ± 2.1 μM/10⁹ spermatozoa, well above the nanomolar ranges per billion spermatozoa reported for other mammals.]]> Thu 25 Aug 2022 12:01:39 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51207 Thu 24 Aug 2023 15:00:51 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51206 Thu 24 Aug 2023 15:00:18 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51205 Thu 24 Aug 2023 14:59:15 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51204 Thu 24 Aug 2023 14:59:02 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39756 Thu 22 Jun 2023 11:39:57 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52633 Thu 19 Oct 2023 15:11:54 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48399 Thu 11 May 2023 13:36:21 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19260 Sat 24 Mar 2018 08:06:38 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:20539 Sat 24 Mar 2018 08:02:43 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:18685 Sat 24 Mar 2018 08:01:06 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:21182 Sat 24 Mar 2018 07:56:06 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29650 Sat 24 Mar 2018 07:41:51 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27633 L-tryptophan > L-tyrosine) were substrates for this enzyme, eliciting the dose- and time-dependent generation of ROS via mechanisms that were enhanced by cell death. This unexpected result was confirmed by analyses of ROS generation in subcellular sperm fractions, which again located a majority of LAAO activity to the sperm head. Equine cryopreservation medium was shown to contain sufficient quantities of aromatic amino acids to activate the LAAO system and generate ROS. The biological significance of this activity was established in an experiment in which physiological concentrations of aromatic amino acids were found to suppress sperm motility but only if dead spermatozoa were present in the same suspension. The combination of aromatic amino acids and nonviable cells was also found to enhance the levels of lipid peroxidation in live spermatozoa. These results suggest the potential significance of LAAO activity in generating the oxidative stress associated with the cryopreservation of equine spermatozoa. It is possible that inhibitors of this enzyme system may facilitate the development of modified cryostorage regimes for clinical validation in vivo.]]> Sat 24 Mar 2018 07:34:05 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27065 Sat 24 Mar 2018 07:25:20 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48243 Sat 11 Mar 2023 12:51:09 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43588 Mon 26 Sep 2022 14:23:56 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51973 Mon 25 Sep 2023 10:52:32 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51972 Mon 25 Sep 2023 10:45:10 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51971 Mon 25 Sep 2023 10:23:50 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40738 Mon 18 Jul 2022 13:12:16 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40400 Mon 11 Jul 2022 13:55:46 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49966 Mon 06 May 2024 15:45:12 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54093 Mon 05 Feb 2024 09:20:48 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49666 Fri 26 May 2023 11:37:51 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43567 Fri 23 Sep 2022 11:57:30 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51354 Fri 01 Sep 2023 13:44:28 AEST ]]>