It was expected that mitochondrial substrates, pyruvate and lactate, would eneryg sperm motility and mitochondrial function better than the glycolytic substrate, glucose, due to direct utilization within the mitochondria. Differential effects of glucose and fructose on hexose metabolism in dog spermatozoa. During this process, the flagella move with high curvature and long wavelength. Many methods have been used to understand the relationship between energy metabolism and sperm function. Osmotic stress stimulates generation of superoxide anion by spermatozoa in horses. The proposed mechanism of ROS production described is also what occurs with addition of the ATP-synthase inhibitor, oligomycin, as Energyy previously.
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So, in conclusion, the lifespan of human spermatozoa is hours, but it depends on the environment, which is to say, the conditions under which they are held. Very simply put, seminal fluid is comprised Rubber track buyer proteins, fructose, water and other components such as vitamins, minerals, etc. Incomplete development of human spermatozoa is associated with increased creatine phosphokinase concentration and abnormal head morphology. From the pituitary gland, the luteinizing hormone surges and stimulates leydig cells present in testicles to produce testosterone. Ultrastructural study of an endogenous energy substrate in spermatozoa of the sea urchin Hemicentrotus pulcherrimus. Male Infertility pp Cite as. When male fertility issues are caused by alterations related to sperm motility, the patient is diagnosed with asthenozoospermia through a Sperm cell energy source analysis SA. Motility is one of the main characteristics of a well developed sperm cell. With the energy provided from the mitochondria Sperm cell energy source energyaxonemal moves towards the flagellum base, which causes the crll to slide down. The Open Forensic Science Sperj. All Rights Reserved.
Energy metabolism is a key factor supporting sperm function.
- Sperm is the male reproductive cell.
- For decades, researchers have been debating whether sperm cells get their fuel, molecules of ATP, from mitochondrial oxidative phosphorylation or glycolysis.
- A spermatozoon, in plural spermatozoa , or sperm cell is the male reproductive cell that is expelled along with the seminal fluid or semen when a man ejaculates.
For decades, researchers have been debating whether sperm cells get their fuel, molecules of ATP, from mitochondrial oxidative phosphorylation or glycolysis. Their work advances our understanding of the cellular physiology of sperm, which in turn may have some bearing on the development of a male contraceptive pill and better in vitro fertility techniques. The investigators decided to tackle proteomic analyses of the tail of human sperm, because previous studies indicated many sperm metabolism proteins are located there.
By identifying all the proteins in the tail, the investigators hypothesized, they could tease out which were the ATP-producing pathways in the cell. Amaral, Oliva and colleagues isolated active sperm cells from semen samples taken from healthy men.
They then cut out the protein bands from the gel and analyzed them by liquid chromatography—mass spectrometry. The team discovered a number of proteins that had not been previously described in human sperm. Some peroxisomal proteins are known to be involved in the oxidation of very long-chain fatty acids. The investigators say that their data contradict a common concept in the literature that sperm cells need to have external substrates for energy production through either oxidative phosphorylation or glycolysis.
The finding of peroxisomal proteins suggests sperm may be able to get energy from internal sources of substrates, such as the long-chain fatty acids, to guard against external energy-source fluctuations.
More from the current issue. Member Login. Where do sperm cells get their energy? At the top left of the figure a phase contrast microscopy image of the sperm cells purified after percoll density selection and CDMACS purification is shown at low magnification to demonstrate the absence of potentially contaminating cells. Click on the image to see a larger version of it. Amaral, A. Proteomics DOI Follow her on Twitter www.
For other uses, see Sperm disambiguation. Some animals like human and bovine have a single typical centriole, known as the proximal centriole, and a second centriole with atypical structure. Asked in Mitochondria Why do sperm have mitochondria in the midpoint? This is only to show the possible evolution of the polyol pathway once the advantage of using fructose as the energy source was established. Tales from the tail: what do we really know about sperm motility? Conidia are spores that germinate independently of fertilization, whereas spermatia are gametes that are required for fertilization.
Sperm cell energy source. Related Questions
Christa R. Darr, Dickson D. Varner, Sheila Teague, Gino A. Cortopassi, Sandipan Datta, Stuart A. Stallion sperm rely primarily on oxidative phosphorylation for production of ATP used in sperm motility and metabolism.
The objective of the study was to identify which substrates included in Biggers, Whitten, and Whittingham BWW media are key to optimal mitochondrial function through measurements of sperm motility parameters, mitochondrial oxygen consumption, and cellular reactive oxygen species ROS production.
It was expected that mitochondrial substrates, pyruvate and lactate, would support sperm motility and mitochondrial function better than the glycolytic substrate, glucose, due to direct utilization within the mitochondria.
Measurements were performed after incubation in modified BWW media with varying concentrations of lactate, pyruvate, and glucose. The effects of media and duration of incubation on sperm motility, ROS production, and oxygen consumption were determined using a linear mixed-effects model. Duplicate ejaculates from four stallions were used in three separate experiments to determine the effects of substrate availability and concentration on sperm motility and mitochondrial function and the relationship of oxygen consumption with cellular ROS production.
The present results indicate that lactate and pyruvate are the most important sources of energy for stallion sperm motility and velocity, and elicit a dose-dependent response. Additionally, lactate and pyruvate are ideal for maximal mitochondrial function, as sperm in these media operate at a very high level of their bioenergetic capability due to the high rate of energy metabolism.
Moreover, we found that addition of glucose to the media is not necessary for short-term storage of equine sperm, and may even result in reduction of mitochondrial function.
Finally, we have confirmed that ROS production can be the result of mitochondrial dysfunction as well as intense mitochondrial activity. ATP is required for sperm motility, hyperactivation, capacitation, acrosome reaction, and thus, subsequent fertilization [ 1 — 3 ].
Recent evidence suggests that equine sperm rely almost entirely on mitochondrial oxidative phosphorylation OXPHOS for the production of ATP, which is utilized for motility and other sperm functions [ 4 — 6 ].
Sperm media for storage and cryopreservation should be formulated with these specific energy requirements in mind, as it appears that there must be a delicate balance of mitochondrial inputs in order to achieve optimal mitochondrial function.
In the process of cellular respiration, mitochondria are responsible for the vast majority of oxygen utilization by the cell [ 7 ]. Oxygen is reduced to water at complex IV of the electron transport chain ETC , and protons are subsequently pumped out of the inner mitochondrial matrix, contributing to the proton-motive force that drives ATP production through ATP-synthase [ 8 ]. Measurement of oxygen consumption is a sensitive and dependable indicator of mitochondrial health, and has been positively correlated with sperm motility in humans and stallions [ 9 — 11 ].
Because equine sperm rely heavily on OXPHOS, it is crucial to provide sperm with the necessary substrates for energy metabolism at a concentration that best supports mitochondrial efficiency in all storage conditions. Inadequate metabolizable substrates can lead to mitochondrial dysfunction resulting in decreased motility and increased production of reactive oxygen species ROS leading to oxidative cell injury [ 12 — 15 ].
Most notably, oxidative stress can lead to lipid peroxidation, loss of sperm motility, loss of mitochondrial membrane potential, and disruption of electron transport, oxidative DNA damage, as well as caspase activation, all leading to the intrinsic apoptotic pathway [ 16 , 17 ]. In contrast, mild oxidative stress has a positive impact on sperm functions necessary for fertilization, such as capacitation and hyperactivation [ 1 , 18 ].
ROS promote capacitation by redox regulation of tyrosine phosphorylation, and may also have a significant positive impact on the ability of sperm to bind the zona pellucida, although the exact mechanisms of this phenomenon have yet to be defined [ 18 ]. Recent reports have also indicated that increased ROS production is associated with the most motile and fertile stallion sperm, and can be used as a biomarker of increased mitochondrial activity [ 4 , 19 ].
The objective of this study was to identify which substrates and substrate doses are key to optimal mitochondrial function through measurements of sperm motility parameters, mitochondrial oxygen consumption MITOX , and cellular ROS production.
It was expected that mitochondrial substrates, pyruvate and lactate, would support sperm motility and mitochondrial function better than the glycolytic substrate, glucose, which requires processing through glycolysis prior to being made available as pyruvate in the mitochondria. We also confirm that ROS in stallion sperm can act both as an indicator of mitochondrial dysfunction as well as an indicator of intense mitochondrial activity, and that a balance is required for maintaining optimal sperm mitochondrial efficiency.
All reagents were purchased from Sigma-Aldrich unless otherwise stated. This media consisted of The 5. This treatment was incorporated in the experiment to mimic the concentration of glucose in a commercially available semen extender.
For Experiment 3, lactate and pyruvate media were made with the base BWW salts, and osmolality was adjusted accordingly to yield media with 0. All media had pH adjusted to 7. Ejaculates for this study were collected in duplicate from eight sexually active light-breed stallions using an artificial vagina Missouri model; Nasco, Ft. An inline nylon micromesh filter Animal Reproduction Systems was used to remove the gel fraction of the ejaculate. A sample for sperm morphology analysis was also aliquoted and suspended in buffered formalin saline.
Sperm million from each ejaculate were washed in each of the media treatments. Briefly, neat semen was added to its respective medium at a ratio of at least in a ml conical-bottom tube.
The supernatant was aspirated and the sperm pellet was resuspended in the respective modified BWW media. Concentration was again estimated with the NucleoCounter SP for each treatment, and parameter measurements were taken according to the experimental design. Experimental endpoints included total motility, progressive motility, and average path velocity.
In Experiment 1, membrane integrity was determined with the NucleoCounter SP following the manufacturer's instructions [ 20 ]. The instrument reported the total percent of viable cells [ 21 ]. For Experiment 3, viability was determined in concurrence with the measurement of ROS production. The percentage of Sytox Green-negative cells was determined as the membrane-intact population, as Sytox Green only penetrates cells with nonintact plasma membranes Molecular Probes [ 22 ].
Cellular ROS production was monitored by measuring sperm superoxide anion O 2. SytoxGreen Molecular Probes , which is impermeant to cells with uncompromised membranes, was used to gate DHE in order to report superoxide production only in viable sperm [ 22 ]. All flow cytometric analyses were performed with a FACScan flow cytometer Becton Dickinson equipped with a nm excitation laser.
The sperm chromatin structure assay SCSA was performed as previously described [ 23 — 26 ]. After 30 sec, 1. All flow cytometry data were acquired in list mode and analyzed using the WinList software Verity Software House , as previously described [ 24 ]. Parameters of measure included: normal; abnormal heads; abnormal acrosomes; tailless heads; proximal droplets; distal droplets; abnormal midpieces; bent midpieces; bent tails; coiled tails; and premature germ cells.
Values are reported as percentages. These experiments utilized the high-throughput BD Oxygen Biosensor System BD Biosciences that incorporates an oxygen-sensitive, ruthenium-based fluorophore tris 4,7-diphenyl-1,phenanthroline ruthenium [II] chloride, or Ru [DPP] 3 Cl 2 into a silicone rubber matrix at the bottom of each well of a well microplate.
The rubber matrix forms an oxygen-permeable barrier while keeping the sensor from directly contacting the cells. As the cells respire, oxygen is transferred from the matrix to the media, and the amount of oxygen that diffuses is linearly related to the amount of fluorescence produced by the probe reaction [ 28 ].
After incubation, oxygen consumption was measured and treatments were added to the wells according to the experimental design. For drug treatments, stock solutions were prepared in dimethyl sulfoxide 0. Measurements were continued every 10 min until 60 min T40, T50, T60 with a final measurement taken at T The plates were placed in the incubator between measurements to avoid decreases in oxygen consumption due to cooling [ 28 ].
Sodium sulfite was used as a positive control in each plate, since it eliminates all molecular oxygen from the media. Oxygen consumption data obtained from the plate assay were subjected to a three-step normalization.
First, raw RFUs for each well were divided by the initial blank reading from each well. This was to account for real or instrument-perceived variations in the fluorophore concentration [ 28 , 29 ]. Second, the values from the first normalization were adjusted to the average values of the media wells without sperm ambient controls for each time point. This normalization was to account for any differences in intensity between time points due to instrument-associated drift [ 28 , 29 ].
Lastly, the normalized RFU value was divided by the percent viability multiplied by the number of sperm per well to get normalized RFUs per 1 million viable sperm. The effects of media and time on sperm motility, ROS production, viability, and oxygen consumption were determined using a linear mixed-effects model with the nlme package in R statistical software [ 30 ].
In the model, stallion was used as a random effect to account for the well-documented interstallion variability, based on the assumption that these stallions are a representative sample from the larger population. Percentage data were transformed with the arcsin of the square root. Model fit was assessed visually with a normal probability plot. Differences between media treatments were compared with Tukey multiple comparison analysis in the multcomp package [ 31 ]. Ejaculates were incubated in six different media containing differing concentrations of key substrates based on a modified BWW media.
Experimental endpoints included CASA motility, viability, and oxygen consumption. It was desired to determine which of the three substrates found in BWW media—glucose, pyruvate, or lactate—was most important for optimal sperm function. Additionally, we wanted to determine if increasing the glucose concentration of BWW to the levels found in commonly available semen extenders had an effect on sperm function. In this experiment, we aimed to determine if the substrate concentration in the media, which indicates the metabolic pathway being utilized, was related to the amount of superoxide anion being produced.
To confirm that the increased basal and maximal oxygen consumption levels associated with media containing 5. Spermatozoa were incubated in media containing different concentrations of lactate or pyruvate: 0. Motility, morphology, and SCSA were recorded for each ejaculate of each stallion in the study to characterize the semen of the stallions that were subjected to experimentation Table 1. There were no significant changes with incubation time for total motility, progressive motility, and viability.
Only the data after 60 min of incubation are presented. Total sperm motility was highest in 5. Progressive motility was significantly higher in 5. Average path velocity was higher in 5. Error bars represent SEM. MITOX was measured in all samples over a period of 90 min. The shape of the curve was sigmoidal, with the highest rates of oxygen consumption occurring between 30 and 60 min, as observed by the steep slopes between these time points.
FCCP treatment stimulated maximal oxygen consumption over the basal level. Differences among media treatments were compared after 60 min of incubation prior to signal saturation Fig. The highest basal levels were observed for 5. Basal oxygen consumption was highest for sperm in the 5. Additionally, maximal oxygen consumption with FCCP treatment was highest in 5.
Similar trends in motility data were observed for the stallions sampled at UC Davis Supplemental Fig. S1 ; all Supplemental Data available online at www.
Viability was not significantly affected by incubation time or media composition. Average ROS levels tended to be higher in 5.