Sturgeon Sperm Research Articles

Induction of meiotic gynogenesis in paddlefish (Polyodon spathula) and its confirmation using microsatellite markers

A protocol for gynogenesis of P. spathula was developed in order to produce inbred lines and to develop a technique to preserve the endangered Chinese paddlefish (Psephurus gladius). Diploid gynogenesis was induced in P. spathula using ultraviolet (UV)-irradiated Amur sturgeon (Acipenser schrenckii) sperm for 4.5-min, 5-min or 5.5-min and subsequent heat shock treatment. UV irradiation of sperm for 5 min at a UV intensity (254 nm) of 863 μw cm−2 was the optimum dose to achieve diploid gynogenesis on the basis of observations on hatching rate of eggs. Three microsatellite loci were used to monitor exclusive maternal inheritance of gynogenetic progenies. The results showed all maternal genome among offspring with no paternal genome. The cytogenetic analysis showed that meiotic gynogenetic diploids possessed 120 chromosomes in metaphase plates, while haploid control groups N1–3 possessed 60 chromosomes.

Potential role of the acrosome of sturgeon spermatozoa in the fertilization process

Sturgeon gametes are unique in that their spermatozoa possess acrosome containing acrosomal enzymes whereas their eggs are perforated by numerous micropyles. Thus the function of acrosome, which undergoes acrosomal reaction and filament formation, is unclear. The acrosomal reaction of sterlet Acipenser ruthenus spermatozoa was induced by sperm exposure to the solution containing Ca2+ and high pH. The rate of affected spermatozoa was evaluated using Soybean Trypsin Inhibitor-Alexa conjugate fluorescent staining. Fertilization and hatching test using sperm of this way disrupted acrosome and non-treated sperm as a control proofed necessity of acrosome integrity for fertilization. Increasing percentage of spermatozoa with disrupted acrosome highly decreased percentage of hatching, in spite of electron microscopy verification that the spermatozoa bearing such disrupted acrosomes were able to reach the micropyle. In addition the significant positive correlation between the ability of spermatozoa to induce acrosomal reaction by activation solution and sperm fertilizing ability suggested that spermatozoa, which are able to activate the acrosomal reaction, are more successful in fertilization.

Spermatozoa Concentration, Seminal Plasma Composition and Their Physiological Relationship in the Endangered Stellate Sturgeon (Acipenser stellatus) and Russian Sturgeon (Acipenser gueldenstaedtii )

Comparative studies of ionic composition, osmolality, protein concentration and pH of seminal plasma along with spermatozoa concentrations were carried out in stellate sturgeon, Acipenser stellatus, and Russian sturgeon, Acipenser gueldenstaedtii. Analysis of A. gueldenstaedtii sperm showed significantly higher concentrations of Na(+) (34.58 ± 4.61 mm), Ca²(+) (0.35 ± 0.12 mm), Mg²(+) (0.70 ± 0.25 mm), Cl(-) (13.50 ± 4.04 mm) and proteins (0.60 ± 0.29 mg/ml) in the seminal plasma than did seminal plasma of A. stellatus: Na(+) (20.08 ± 10.75 mm), Ca²(+) (0.28 ± 0.06 mm), Mg²(+) (0.29 ± 0.05 mm), Cl(-) (7.50 ± 3.00 mm) and 0.30 ± 0.11 mg/ml proteins. Significantly higher concentration of K(+) (5.42 ± 1.06 mm) was observed in A. stellatus compared to A. gueldenstaedtii K(+) (2.29 ± 0.50 mm). Concentration of Na(+) was positively correlated with osmolality (r = 0.819), levels of Cl(-) (r = 0.922) and Mg²(+) (r = 0.727) and pH (r = 0.848). The concentration of Mg²(+) was positively correlated with protein concentration (r = 0.774), Na(+) (r = 0.727), Cl(-) (r = 0.872) and Ca²(+) (r = 0.801). A positive relationship was also found between concentration of K(+) and spermatozoa concentration (r = 0.709). Results revealed strong inter-species differences in several parameters. The data should be useful for artificial fertilization and for cryopreservation of sturgeon sperm.

Comparative analysis of milt quality and steroid levels in blood and seminal fluid of Persian sturgeon males, Acipenser persicus during final maturation induced by hormonal treatment

Steroids both in seminal fluid (SF) and blood serum (BS) as well as the milt quality (sperm motility and sperm production) were investigated during final maturation of Persian sturgeon. The BS levels of testosterone (T), 11-Ketotestosterone (11-KT), progesterone (P), 17α,20β,21-trihydroxy-4-pregnen-3-one (20βS), cortisol (C) and 17α,hydroxyprogesterone (OHP) elevated after pituitary preparation (PP) treatment and then decreased during stripping period for spermiating males. Such elevations did not occur for non-spermiating individuals and steroids remained in basal levels after PP treatment until the end of stripping period. For both groups (spermiating and non-spermiating fish), the BS levels of 17α,20β-dihydroxy-4-pregnen-3-one (DHP) did not show significant changes during experiment. During stripping period, the values of all tested steroids were significantly lower in SF than in BS of spermiating males. SF levels of 20βS and 11-KT showed a decreasing trend and the other steroids were unchanged during this period. Significant positive correlations were found between the values of 20βs and 11-KT in BS with their levels in SF. Also, BS and SF levels of 20βs and 11-KT were positively correlated with sperm motility characteristics (percentage and duration of motility) and sperm production (sperm density and milt volume), respectively. The results showed the probable involvement of 20βs, P, OHP, T, 11-KT and C in final maturation of Persian sturgeon, especially 20βs and 11-KT had good correlations with qualitative parameters of milt. The lower levels of steroids in SF than those in BS might also be essential for viability of Persian sturgeon spermatozoa. Probably, there are mechanisms that stabilize the concentrations of a number of hormones in the SF.

Influence of environmental related concentrations of heavy metals on motility parameters and antioxidant responses in sturgeon sperm

The effects of heavy metals (Cd, Cr and Cd + Cr) on the motility parameters and oxidative stress of sterlet ( Acipenser ruthenus) sperm were investigated in vitro. Sturgeon sperm were exposed for 2 h to heavy metals at environmental related concentrations (0.1 mg L −1 Cr, 0.001 mg L −1 Cd, 0.1 mg L −1 Cr + 0.001 mg L −1 Cd) and higher concentrations (5.0 mg L −1 Cr, 0.05 mg L −1 Cd, 5.0 mg L −1 Cr + 0.05 mg L −1 Cd). Results revealed that environmental concentrations of heavy metals had no significant influence on motility parameters and antioxidant responses indices in sturgeon sperm, except for LPO level and SOD activity. But higher concentrations of these metals induced oxidative tress in sturgeon sperm in vitro, associated with sperm motility parameters inhibition. Our results suggest that using of sperm in vitro assays may provide a novel and efficiently means for evaluating the effects of residual heavy metals in aquatic environment on sturgeon.

Evaluating the function of calcium antagonist on the Cd-induced stress in sperm of Russian sturgeon, Acipenser gueldenstaedtii

In the current study, the sperm of Russian sturgeon ( Acipenser gueldenstaedtii) was used to evaluate the roles of Verapamil (VRP), a calcium channel blocker, against cadmium (Cd)-induced stress. Sturgeon sperm were exposed for 2 h at 50 μg/L VRP, 5.0 μg/L Cd, the mixture of 50 μg/L VRP + 5.0 μg/L Cd, 50 μg/L Cd and the mixture of 50 μg/L VRP + 50 μg/L Cd. After exposure, the sperm motility parameters (motility and velocity), oxidative stress levels (lipid peroxidation [LPO] and carbonyl protein [CP]) and antioxidant enzyme activities (superoxide dismutase [SOD], glutathione reductase [GR], glutathione peroxidase [GPx]) were measured in sturgeon sperm. Compared to the control, Cd-induced stress was apparent as reflected by depressed motility parameters, induced oxidative stress and inhibited antioxidant enzyme activities at both Cd concentrations. In the presence of VRP, Cd-induced stress was reduced in sturgeon sperm, especially all the measured parameters in the sperm exposed at 5.0 μg/L Cd returned to control levels, expect for the sperm motility. The present results indicate that VRP can reduce the Cd-induced stress in sturgeon sperm and suggest that using of sperm in vitro assays may provide a novel and efficient means for evaluating the effects of residual metals in the aquatic environment of sturgeon.

Study of the Antioxidant Properties of Porphyrins and their Complexes with Metals

The synthetic analogues of natural porphyrins are widely used in medicine as pharmaceutical diagnostic markers. It was shown the possibility of applying porphyrins in the therapy of the diseases, connected with the development of oxidative stress. The paper presents the results of the study of antioxidant activity of the free base meso-tetrakis(3,5di-tert-butyl-4-hydroxyphenyl)porphyrin R 4 PH 2 , as well as non-substituted analogue - meso-tetraphenylporphyrin (TPPH 2 ) in the conditions of autooxidation and under promotion of oxidation by organotin compounds. The ability of the free base of porphyrin containing antioxidant 2,6-di-tert-butyl phenolic groups to decrease the oxidation by peroxide of lipids liver gomogenates, sturgeon sperm, fish feed has been studied. Accumulation of intermediate oxidation products from liver homogenates, sperm of the Russian sturgeon (Acipenser guldenstadti Brandt) as a stable complex with thiobarbituric acid (TBARS) and oxidation products from fish feed (hydroperoxides ROOH) was monitored by spectrophotometry and iodometric titration, respectively. The efficiency of antioxidative action (EAA) of studed porphyrins in each series of experiences with varying duration of lipids peroxidation in liver homogenates was calculated as EAA = [(C 0 -C 1 )/C 0 ]·100%, where C 1 is TBARS concentration in homogenates of liver containing the studied compounds and C 0 in a control experiment without additions. If the value of EAA factor was positive, it was considered that the testing material shows the antioxidative action; in the case of negative EAD factor it was considered that the testing material shows the prooxidative activity. The initial concentration of the studied compounds was 0,1 mM. In the model system the antioxidant activity of R 4 PH 2 in peroxidation of liver lipids remains almost constant in the wide interval of concentrations (0,01 - 10 mM). It was established that in the middle stages of the oxidation process (3 h, 24 h) the antioxidant action of TPPH 2 is inverted to the prooxidant. The presence of 2,6-ditert-butylphenolic groups in the free base porphyrin macrocycle results in an inhibitory effect. The introduction of the redox-active ion metal in the macrocycle reduces the inhibition effect of 2,6-di-tert-butylphenol fragments in oxidative destruction of liver lipids. The prooxidantive properties of TPPH 2 during the oxidive destruction of the lipids of fish fodder were observed. Addition of this porphyrin to lipid drawing from the fish fodder in the concentration 150 mg/ kg of fodder leads to an increase in the level the formation of primary oxidation products, namely, hydroperoxides ROOH. The organic derivatives of tin, acting as superecotoxicants, promote peroxidation of lipids in the drawing from the fish fodder. The greatest promoting effect of the lipid peroxidation was observed in the presence of СН 3 SnCl 3 . It was shown earlier that toxicity of heavy metals compounds could be connected with complexation of important bio dartboards as well as development of radical processes. So it is possible to use the active radicals traps as antidotes. With the aim of increasing of toxicoprotector efficiency, we offer to use compounds containing antioxidation part and complexating groups in molecule. Such compounds can be porphyrinic systems, but it is necessary to take into account the possibility of revealing of prooxidative properties by these compounds. It is discovered, that TPPH 2 strengthens the promoting influence of the methyl derivatives of tin on the level of accumulation of hydroperoxides in the lipid drawing from the fish fodder. Since the oxidative activity of TPPH 2 and R n SnCl 4-n are summed consequently the application of TPPH 2 for detoxication of R n SnCl 4-n is inadvisable. The promoting activity of organotin species in the presence of the porphyrin containing sterically-hindered phenolic moieties decreases significantly when compared with the activity of organotins alone. R 4 PH 2 was superior to the standard antioxidants α-tocopherol, 2,6-di(tert-butyl) phenols, 2,6-di(tert-butyl)-4-methylphenol (ionol).

Sperm proteins in teleostean and chondrostean (sturgeon) fishes

Sperm proteins in the seminal plasma and spermatozoa of teleostean and chondrostean have evolved adaptations due to the changes in the reproductive environment. Analysis of the composition and functions of these proteins provides new insights into sperm motility and fertilising abilities, thereby creating possibilities for improving artificial reproduction and germplasm resource conservation technologies (e.g. cryopreservation). Seminal plasma proteins are involved in the protection of spermatozoa during storage in the reproductive system, whereas all spermatozoa proteins contribute to the swimming and fertilising abilities of sperm. Compared to mammalian species, little data are available on fish sperm proteins and their functions. We review here the current state of the art in this field and focus on relevant subjects that require attention. Future research should concentrate on protein functions and their mode of action in fish species, especially on the role of spermatozoa surface proteins during fertilisation and on a description of sturgeon sperm proteins.

Staining of sturgeon spermatozoa with trypsin inhibitor from soybean, Alexa Fluor®488 conjugate for visualization of sturgeon acrosome

Summary Trypsin-like activity, similar to acrosin, is present in sturgeon spermatozoa and can be a potential target for trypsin inhibitors. The objective of this work was to use a fluorescent soybean trypsin inhibitor (SBTI) conjugate with the Alexa Fluor® 488 dye for visualization of the sturgeon acrosome. After incubation with SBTI-Alexa, a strong signal was observed both in the acrosome and midpiece or implantation fossa region. We have also found that SBTI-Alexa staining can be combined with PI viability test. Detailed examination of staining pattern revealed that SBTI-Alexa can stain either acrosome or whole sperm. Staining of whole sperm correlated with dead staining (r2 = 0.94, P < 0.01). However, in fresh semen most cells (93–97%) were not stained with SBTI-Alexa, probably due to intact acrosomes. Further studies should test if SBTI-Alexa can be applied to monitor the acrosome status during the acrosome reaction and cryopreservation.

Viability and fertilizing capacity of cryopreserved sperm from three North American acipenseriform species: a retrospective study

Populations of sturgeon across the globe are threatened due to unregulated harvest and habitat loss, and the status varies among species across North America. Ready access to viable and functional sperm would contribute to recovery programmes for these species. In this study, we examined the motility, viability (cell membrane integrity) of cryopreserved sperm from three North American acipenseriform species and fertilizing capacity. Milt samples were collected from captive shortnose sturgeon (Acipenser brevirostrum), wild paddlefish (Polyodon spathula) and pallid sturgeon (Scaphirhynchus albus) and cryopreserved using combinations of Modified Tsvetkova �s (MT) extender, Original Tsvetkova�s extender, and modified Hanks� balanced salt solution, along with the cryoprotectants methanol (MeOH) or dimethyl sulfoxide (DMSO). A dual-staining technique using the fluorescent stains SYBR-14 and propidium iodide was employed with flow cytometry to determine the percentages of spermatozoa that were viable by virtue of having intact membranes. The percentage of viable spermatozoa ranged from 5% to 12% in shortnose sturgeon, 30–59% in paddlefish, and 44–58% in pallid sturgeon. In the first experiment with shortnose sturgeon sperm, methanol allowed for higher values for dependent variables than did DMSO, and sperm viability generally correlated with post-thaw motility. However, fertilization rate, neurulation, or hatching rates were independent from these factors. In the second experiment with shortnose sturgeon, 5% MeOH combined with MT yielded higher values for all parameters tested than the other combinations: viability was correlated with motility, fertilization rate, and hatching rate. Overall, viability and post-thaw motility was not affected by the use of hyperosmotic extenders (OT) or cryoprotectants (DMSO), but their use decreased fertilization percentages. For paddlefish sperm (experiment 3), MT combined with 10% MeOH was clearly a good choice for cryopreservation; viability and motility results were correlated, but independent of fertilization. For pallid sturgeon sperm (experiment 4), MT with 5–10% MeOH showed significantly higher sperm quality and fertilization parameters. Membrane integrity can be used as a predictor of fertilization by cryopreserved sperm, however additional sperm quality parameters, supplementary to motility and membrane integrity, would be useful in the refining and optimizing cryopreservation protocols with acipenseriform sperm.

Isolation and preliminary characteristics of β-N-acetylglucosaminidase in the sperm of Siberian sturgeon (Acipenser baerii) and rainbow trout (Oncorhynchus mykiss)

The aim of this study was to characterize the enzyme β-N-acetyglucosaminidase (β-NAGase) in the milt and spermatozoa extracts from Siberian sturgeon and rainbow trout. After ion exchange chromatography one protein peak showed β-NAGase activity in sturgeon milt plasma and sperm extracts of both species. Surprisingly, two protein peaks showing β-NAGase activity were found in rainbow trout milt plasma. The molecular mass of β-NAGase was estimated by gel filtration as 127 kDa for rainbow trout spermatozoa, 271 kDa for sturgeon spermatozoa, and 74 kDa for milt plasma from both species. The kinetic parameters were determined for milt plasma and sperm extracts. The optimum pH of the β-NAGases was 3.8 for sturgeon milt plasma, 4.4 for sturgeon sperm extract, and 4.4–4.8 for milt plasma and sperm extract from rainbow trout. Km value of the β-NAGases was 0.212, 0.563, 0.779 mm for sturgeon milt plasma, sturgeon sperm extract or rainbow trout extract, respectively. The β-NAGase from sperm extracts in both species showed 100% activity even after incubation at 56°C by 20 min, whereas its activity was decreased to 23% in sturgeon milt plasma and to 2% in trout milt plasma.

Morphology, chemical contents and physiology of chondrostean fish sperm: a comparative study between Siberian sturgeon (Acipenser baerii) and sterlet (Acipenser ruthenus)

Summary The present study was carried out with two sturgeon species, Siberian sturgeon (Acipenser baerii) and sterlet (A. ruthenus) to compare spermatological parameters to better understand inter-species differences. Significant differences between morphometric features were observed such as acrosome length, acrosome width, head length, midpiece width and flagellar length, while midpiece length did not reveal such differences. The sterlet has a shorter spermatozoon than the Siberian sturgeon. Ultrastructural parameters vary significantly in terms of length of the nucleus, diameter of the endonuclear canals (EC), size of posterolateral projections (PP) and diameter of flagellum. Mean values for density of spermatozoa in the semen, seminal plasma pH, osmolality (mOsmol kg−1), along with Ca2+, Na+, K+, Cl− ions concentrations (mm) were determined to be 0.61 ± 0.37 × 109, 8.16 ± 0.18, 77.20 ± 52.28, 0.24 ± 0.06, 31.39 ± 10.21, 3.51 ± 1.10, 14.00 ± 4.30 in A. baerii and 0.41 ± 0.32 × 109, 8.13 ± 0.19, 50.74 ± 6.27, 0.16 ± 0.11, 20.11 ± 3.78, 1.26 ± 0.54, 6.11 ± 0.60 in A. ruthenus, respectively. Significant differences were observed in Na+, K+ and Cl− concentrations in the seminal plasma as well as in sperm velocity. The percentage of motile spermatozoa did not show any significant difference between the two species. Comparing the results of this study with published literature data on sturgeon spermatozoa reveals that morphological and ultrastructural parameters of spermatozoa together with some parameters of the seminal fluid and spermatozoa velocity can be used in comparative spermatology to better understand inter-species differences. The observed biochemical and physiological differences should be also considered for the development of methods for controlled reproduction and for sperm cryopreservation techniques.

The optimization of the protocol for immunofluorescence on fish spermatozoa

In comparison with mammals, the fertilization of fish occurs predominantly outside the organism in a water environment, where fish spermatozoa require specific conditions to interact with oocytes. It is evident that optimal conditions for fish and mammalian spermatozoa are quite different. This paper describes a special approach to handling fish (common carp and Siberian sturgeon) spermatozoa in comparison with the samples originating from mammals (boar). This approach concerns not only the differences in the composition of the media applied but also primarily emphasizes the concrete parts of the immunofluorescence protocol determining accurate results. Individual parts of the protocol for indirect immunofluorescence of mammalian sperm were changed step by step and modified protocols were applied to immunofluorescence experiments with carp and sturgeon spermatozoa. By evaluating the changes in the integrity of the fish sperm head and flagellum, we selected the steps and corresponding conditions that are crucial for handling the fish spermatozoa. Based on our results, it may be concluded that when working with fish spermatozoa, the cells attached to the microscopic slides must not desiccate prior to the fixation, which is a usual step when working with mammalian sperm. The second crucial step is the necessity to fix the fish spermatozoa, especially when the research is focused on the structure of the flagellum. The impact of the temperature conditions is rather low, but working at low temperatures, except for the period of incubation with antibodies, leads to a higher number of unaffected cells.

Acrosome staining and motility characteristics of sterlet spermatozoa after cryopreservation with use of methanol and DMSO

In this study we describe acrosome staining and motility characteristics of fresh and cryopreserved sterlet ( Acipenser ruthenus L.) spermatozoa using soybean trypsin inhibitor-Alexa conjugate fluorescent staining and computer-aided sperm analysis (CASA), respectively. Methanol or dimethylsulfoxide (DMSO) were used as cryoprotectants. After cryopreservation a decline in sperm motility characteristics occurred, but no differential effect between cryoprotectant was observed. Cryopreservation caused a significant increase in the percentage of spermatozoa with acrosome stained by SBTI-Alexa for samples cryopreserved using DMSO compared to methanol. These data suggest that the low usefulness of DMSO for cryopreservation of sturgeon spermatozoa is related to its harmful specific effect towards the acrosome, probably by causing its precocious triggering, much before any egg contact.

Fine structure and morphology of sterlet ( Acipenser ruthenus L. 1758) spermatozoa and acrosin localization

Ultrastructure of sterlet Acipenser ruthenus L. 1758 sperm was examined by scanning and transmission electron microscopy, which allowed us to use various methods for visualizations of different parts of sterlet spermatozoa. Sperm cells possess a head with a distinct acrosome, a midpiece and a single flagellum surrounded by the flagellar plasma membrane. The average length of the head including the acrosome and the midpiece was estimated as 5.14 ± 0.42 μm. Nine to 10 posterolateral projections were derived from the acrosome. Three inter-twining endonuclear canals bounded by membranes traversed the nucleus in its whole length from the acrosome to the implantation fossa. Acrosin was located in all the three parts (acrosome, endonuclear canals and implantation fossa). The proximal and distal centrioles located in the midpiece compacted of nine peripheral triplets of microtubules. One cut of the midpiece contained from two to six mitochondria with area of 215 ± 85 nm 2 in average. The flagellum was 42.47 ± 1.89 μm in length with typical eukaryotic organization of one central pair and nine peripheral pairs of microtubules. It passed through a cytoplasmic channel in the midpiece, which was formed by an invagination at the plasmalemma. The flagellum gradually developed two lateral extensions of its plasma membrane, so-called “fins”. Detected morphological variation can be described by four principal component axes corresponding to groups of individual morphometric characters defined on the sperm structures. Correlations among the characters indicate that the sperms are variable in their shape rather than size. Significant variation among examined fish individuals was found only in flagellum and nucleus length. Comparison between the present and previous studies of morphology of sturgeon spermatozoa confirmed large inter- and/or intra-specific differences that could be of substantial taxonomic value.

Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy

Available data concerning the sperm morphology of teleost fishes demonstrate wide variation. In the present study, the spermatozoa of Siberian sturgeon (Acipenser baerii Brandt, 1869), a chondrostean fish, was investigated. In contrast with teleost fish, chondrostean spermatozoa have a head with a distinct acrosome, whereas other structures, such as a midpiece and a single flagellum, are present in spermatozoa of most species. The average length of the head including the acrosome and the midpiece was 7.01+/-0.83 microm. Ten posterolateral projections derived from the acrosome were present on a subacrosomal region, with mean lengths of 0.94+/-0.15 microm and widths of 0.93+/-0.11 microm. The nucleus consisted of electrodense homogeneous nuclear chromatin. Three intertwining endonuclear canals, bound by membranes, traversed the nucleus longitudinally from the acrosomal end to the basal nuclear fossa region. There were between three and six mitochondria, two types of centrioles (proximal and distal) in the midpiece and two vacuoles composed of lipid droplets. The flagellum (44.75+/-4.93 microm in length), originating from the centriolar apparatus, had a typical 9+2 eukaryotic flagellar organization. In addition, there was an extracellular cytoplasm canal between the cytoplasmic sheath and the flagellum. A principal components analysis explained the individual morphological variation fairly well. Of the total accumulated variance, 41.45% was accounted for by parameters related to the head and midpiece of the sperm and the length of the flagellum. Comparing the present study with previous studies of morphology of sturgeon spermatozoa, there were large inter- or intra-specific differences that could be valuable taxonomically.

Characteristics of acid phosphatase from Russian sturgeon (Acipenser gueldenstaedtii) spermatozoa

Characteristics of acid phosphatase from Russian sturgeon (Acipenser gueldenstaedtii) spermatozoa

Cryopreservation of Chinese sturgeon (Acipenser sinensis) sperm

Journal of Applied IchthyologyVolume 22, Issue s1 p. 384-388 Cryopreservation of Chinese sturgeon (Acipenser sinensis) sperm L. Liu, L. LiuSearch for more papers by this authorQ. Wei, Q. WeiSearch for more papers by this authorF. Guo, F. GuoSearch for more papers by this authorJ. Zhang, J. ZhangSearch for more papers by this authorT. Zhang, T. ZhangSearch for more papers by this author L. Liu, L. LiuSearch for more papers by this authorQ. Wei, Q. WeiSearch for more papers by this authorF. Guo, F. GuoSearch for more papers by this authorJ. Zhang, J. ZhangSearch for more papers by this authorT. Zhang, T. ZhangSearch for more papers by this author First published: 10 July 2007 https://doi.org/10.1111/j.1439-0426.2007.00991.xCitations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume22, Issues1December 2006Pages 384-388 RelatedInformation

Investigation on dispermic androgenesis in sturgeon fish. The first successful production of androgenetic sturgeons with cryopreserved sperm

Induced diploid androgenesis is considered as a valuable tool for restoration of endangered or extinct species from cryopreserved spermatozoa. The method of dispermic androgenesis was developed in sturgeon fishes whose threatened status requires urgent conservation efforts. The method includes genetic inactivation of eggs, their insemination with concentrated sperm (to cause polyspermy), and the heat shock that facilitates the fusion of male pronuclei. Restoration of diploid state of androgenotes by fusion of two sperm nuclei allows androgenetic progeny to have a heterozygosity level as similar as in a regular crossing. Using this method, viable androgenetic progenies were obtained for the first time in the Siberian, Russian, stellate, and beluga sturgeons. Then a number of androgenetic nucleocytoplasmic hybrids was obtained. Androgenetic hybrids were shown to have nuclear DNA of paternal species and mitochondrial DNA of maternal species. The first experiments in which cryopreserved sperm was used have demonstrated that dispermic androgenesis may be applied to restore sturgeons from their cryopreserved spermatozoa. Haploid androgenesis was also used to examine whether cryopreservation procedures cause lesions in DNA of sturgeon spermatozoa.

Ultrastructural study of spermatozoa of the paddlefish, Polyodon spathula

Paddlefish, Polyodon spathula, spermatozoa were examined by transmission electron microscopy. Their structure has the same characteristic architectural features as sturgeon spermatozoa. Paddlefish spermatozoa are of the primitive type and consist of a rod-shaped head, a midpiece and a long flagellum. The head is about 5.15 mm in length and contains the nucleus and an apical acrosomal complex. Inside the nucleus there are three nuclear channels that begin in the subacrosomal area and have a triple helical arrangement. An nuclear fossa is present centrally, at the posterior end of the nucleus. The midpiece contains a pair of centrioles in a perpendicular arrangement, mitochondria and a narrow cytoplasmic sleeve. The flagellum has a central axoneme with a 9 + 2 pattern and two lateral projections or fins.