Tadashi Nakada

Kagoshima University, Kagosima, Kagoshima, Japan

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Publications (26)40.48 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract 1. The objective of this study was to examine whether addition of plumping fluid (PF) to Lake's solution (LS) for storage of fowl spermatozoa in vitro at 4°C can prolong survival and improve the quality of spermatozoa. 2. In experiment 1, aliquots of spermatozoa were stored in vitro in LS alone and LS containing 10%, 25%, 50% and 75% (v:v) PF for 0.5, 24, 48, 72, 96 and 120 h at 4°C. After the end of each storage period, spermatozoa were evaluated for their viability, mobility and penetrability. Viability was determined using SYBR-14 and propidium iodide (PI) staining. Mobility was assessed using an Accudenz assay. Penetrability was assessed using spermatozoa-inner perivitelline layer (IPL) interaction assay. 3. In experiment 2, aliquots of spermatozoa were stored in vitro in LS alone and LS containing 25% and 50% (v:v) PF for 0.5, 24, 48 and 72 h at 4°C, and then fertility of the spermatozoa was evaluated using intravaginal artificial insemination (AI) in hens. 4. Storage of spermatozoa in LS alone resulted in loss of viability, mobility, penetrability and fertility within 48 h. In contrast, no loss of viability and penetrability was observed for the spermatozoa stored for 48, 96, 72 and 48 h in LS containing 10%, 25%, 50% and 75% (v:v) PF, respectively. In particular, fertilising capacity was not lost for the spermatozoa stored in the presence of 25% or 50% PF in LS for 48 and 24 h, respectively. 5. In conclusion, these findings demonstrated that in vitro exposure of fowl spermatozoa to PF during hypothermic storage in LS prolonged spermatozoa survival. A 25% (v:v) level of inclusion of PF in LS may be effective for the improvement of viability, penetrability and fertilising ability of the stored spermatozoa.
    British Poultry Science 04/2013; 54(2):270-80. · 1.15 Impact Factor
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    ABSTRACT: The aim of this study was to determine the site of enzyme release from the acrosome and the fate of the acrosomal cap during the process of acrosome reaction (AR) in fowl sperm. Gelatin substrate coverslips with halos were subjected to scanning electron microscopy to determine the site from which acrosomal proteolytic enzyme was released to form a halo around the acrosome of individual sperm. Aliquots of sperm treated with solubilized inner perivitelline layer (IPL) containing 5 mmol CaCl(2) were simultaneously subjected to fluorescent staining with fluorescein isothiocyanate-labeled peanut agglutinin and scanning electron microscopy to evaluate AR of sperm and to examine the status of the acrosomal region, respectively. Inside the halos, a gelatin-free (proteolyzed gelatin) layer was found extending some distance around the acrosome of sperm. All of the sperm showing the formation of halos on gelatin had a single circular opening around their subacrosomal rod at the base of the acrosomal cap. Interaction of sperm with solubilized IPL in the presence of 5 mmol CaCl(2) resulted in 41.4 ± 1.8% of the sperm to undergo AR, as evaluated by fluorescein isothiocyanate-labeled peanut agglutinin. Similarly, as observed using scanning electron microscopy, 38.2 ± 2.3% of the sperm treated with solubilized IPL plus 5 mmol CaCl(2) had exposed subacrosomal rod. In all sperm examined, no sign of disruption of the acrosomal membrane was found in the apical region of the acrosome. Rather, the acrosomal caps were found intact detached from the acrosomal region of the sperm, indicating that AR of fowl sperm resulted in the intact removal of the acrosomal cap. Based on these experimental observations, we suggest that the process of AR in fowl sperm is unique; the release of the acrosomal proteolytic enzyme may occur through a single circular opening formed at the base of the acrosomal cap and the acrosomal cap is detached in intact form from the posterior acrosomal region of the sperm.
    Poultry Science 03/2013; 92(3):798-803. · 1.52 Impact Factor
  • Khin Mar Lay, Tadashi Nakada, Hideki Tatemoto
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    ABSTRACT: The present study was conducted to delineate whether N-glycosylation of zona pellucida (ZP) glycoproteins occurred during meiotic maturation and whether this N-glycosylation played a role in sperm-ZP interactions of porcine cumulus denuded oocytes (DOs). After mechanical removal of cumulus cells from cumulus oocyte complexes (COCs), DOs were cultured for 44 h in in vitro maturation (IVM) culture. The experiments were carried out to determine the effects of tunicamycin, a specific N-glycosylation inhibitor, for various intervals during IVM on sperm-ZP interactions in porcine DOs. The results determined that DOs could induce meiotic maturation, although the maturation rate of DOs was earlier than that of COCs. In addition, N-glycosylation of ZP glycoproteins occurred during meiotic maturation and was crucial in sperm-ZP interactions, was responsible for sperm penetration, sperm binding to ZP and induction of acrosome reaction in ZP-bound sperm. However, the inhibition of N-glycosylation by tunicamycin during IVM did not influence ZP hardness and male pronuclear formation, indicating that this N-glycosylation was involved in the initial stage of fertilization. We conclude that 24-44 h of N-glycosylation of ZP glycoproteins during meiotic maturation was crucial in sperm penetration and sperm binding to ZP and the induction of acrosome reaction in sperm bound to ZP of porcine DOs.
    Animal Science Journal 01/2013; 84(1):8-14. · 1.04 Impact Factor
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    ABSTRACT: The objective of this study was to examine whether domestic fowl (Gallus domesticus) sperm undergo maturation in their capacity for survival and fertilization in the male reproductive tract. Sperm collected from the testis, epididymis and the proximal, middle and distal vas deferens were simultaneously stored in vitro in minimum essential medium (MEM) at 39°C for 0, 3 and 6h, and at 4°C for 24 and 48h. Sperm membrane integrity was measured using the dual fluorescent stain SYBR-14/propidium iodide (PI). Aliquots of sperm from the various sites were subjected to artificial insemination (AI) into the uteri of hens to assess the duration of sperm survival in the oviduct and to determine the fertility status of the sperm. Testicular sperm exhibited a very low capacity to survive under in vitro liquid storage conditions, irrespective of the storage temperature used, and in the oviduct, and they had a low ability to fertilize the ovum. On the contrary, sperm from the distal vas deferens had a higher survival rate during in vitro storage periods, a longer life span in the oviduct, and high fertility. Survival and fertilizing capacity of the sperm recovered from the testes increased gradually (P<0.05) from the testes to the distal vas deferens. In conclusion, we suggest that fowl sperm may undergo functional maturation through a process of gradual changes in their survival and fertilization capacities during their passage through the successive parts of the male reproductive tract.
    Animal reproduction science 10/2011; 128(1-4):129-36. · 1.56 Impact Factor
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    ABSTRACT: The objective was to examine, in vitro, the motility, acrosomal proteolytic activity (APA), and penetrating ability of fowl sperm recovered from the testis and epididymis, as well as the proximal, middle, and distal vas deferens, to assess the potential fertilizing ability of sperm as a function of maturation. A motile sperm separation technique was used to estimate sperm motility with Accudenz, a gelatin slide technique was used to measure the diameter of the halo around the acrosome of individual sperm as an indication of APA, and a sperm-inner perivitelline layer (IPL) interaction assay was done to estimate the number of hole formations as an indication of sperm penetration into the IPL. Sperm in the testis exhibited the least motility, produced the smallest halos, and created the least number of holes per 0.25 mm(2). Motility, diameter of the halo, and number of holes increased gradually (P < 0.05) from the epididymis to the distal vas deferens and were markedly different (P < 0.05) between testicular and deferent duct sperm. Based on these in vitro experimental findings, we inferred that fowl sperm undergo a gradual process of maturational changes in motility, APA, and penetrability as a means of acquiring potential fertility during their passage throughout the male genital tract.
    Theriogenology 07/2011; 76(6):1100-9. · 2.08 Impact Factor
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    ABSTRACT: The objective of this study was to examine the binding potential of sperm to the epithelium of the sperm storage tubules (SST) in vitro and in vivo to assess the functional maturation of fowl sperm. Sperm from the testis, epididymis, as well as the proximal, middle and distal vas deferens were incubated in vitro with either the uterovaginal junction (UVJ)- or infundibular tissue containing SST at for 30 min. Aliquots of sperm were also artificially inseminated into the uteri of hens, and the UVJ and infundibulum were collected 24 h post artificial insemination (AI). After incubation and AI, tissues were washed to remove loosely adhered sperm and subjected to fluorescence staining with 4', 6-diamidino-2-phenylindole, dihydrochloride (DAPI) for counting the number of bound sperm per 0.25 mm2 of surface area. Sperm from the testis, epididymis, and the three segments of the vas deferens exhibited their differential (p
    Asian Australasian Journal of Animal Sciences 01/2011; 24(9). · 0.64 Impact Factor
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    ABSTRACT: The objective was to determine whether N-glycosylation of zona pellucida (ZP) glycoproteins occurred during meiotic maturation of porcine oocytes, and whether this had a role in fertilization. In the first of three experiments, carbohydrate residues in the ZP of in vitro matured porcine oocytes were blocked with various lectins and the influence of such blocking on sperm-ZP interactions was studied. The second experiment used a lectin-binding assay to determine whether the number of GlcNAc residues in ZP was changed by N-glycosylation during in vitro maturation (IVM) of porcine oocytes. The last experiment determined the effects of tunicamycin, a specific N-glycosylation inhibitor, for various intervals during IVM, on sperm-ZP interactions in porcine oocytes. The primary findings were that: 1) N-glycosylation of GlcNAc residues in porcine ZP occurred during the first 24 h of IVM; and 2) such glycosylation was indispensible for sperm-ZP interactions, e.g., number of sperm bound to ZP, acrosome-reacted sperm, sperm penetration rate, and level of polyspermy (P < 0.05). However, blocking N-glycosylation by tunicamycin treatment during IVM did not adversely influence the progression of oocytes to meiotic metaphase II and male pronucleus formation, indicating that this glycosylation was involved only in the initial stages of fertilization. We inferred that the increase in terminal GlcNAc residues in ZP glycoprotein through new N-glycosylation during the first 24 h of meiotic maturation played a critical role in porcine ZP acquiring the capacity to accept sperm.
    Theriogenology 01/2011; 75(6):1146-52. · 2.08 Impact Factor
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    ABSTRACT: Comparisons of properties between skeletal ryanodine receptor 1 (sRyR1)-heterozygous-mutated and normal types of meat were carried out in pigs using PSE (pale, soft and exudative) meat found during the butchering process. All samples considered to be PSE meat showed irregular running and disorder of the muscle fibers and a wider inter-fiber space upon light microscopic observation. Electron microscopy revealed disintegration, twisting, and disorder of the myofibril arrangement and elimination of the Z line in PSE meat, compared with normal meat. Meat property tests demonstrated greater decreases in water holding capacity, moisture and sarcoplasmic protein, and higher values for the meat color index in PSE meat than in normal meat, but there were no differences in these factors between genetically normal and sRyR1-heterozygous PSE meat. On the other hand, higher and values were observed in sRyR1-heterozygous than in normal PSE meat, and similar alterations to the a* value were observed in terms of the amount of myoglobin and density of the 17-kDa protein band, corresponding to the molecular mass of myoglobin, on SDS-PAGE gels. These results suggest that sRyR1-heterozygous PSE pork contains much more myoglobin than genetically normal PSE meat.
    Asian Australasian Journal of Animal Sciences 01/2010; 23(9). · 0.64 Impact Factor
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    ABSTRACT: Technical refinement of boar sperm cryopreservation is indispensable for effective breeding of the rare Okinawan native pig, the Agu. The objective of the present study was to determine whether addition of low-density lipoprotein (LDL) extracted from hen egg yolk to the freezing extender improves the characteristics of cryopreserved Agu spermatozoa. Ejaculated Agu sperm frozen in extender supplemented with 2, 4, 6, 8 or 10% LDL instead of egg yolk was thawed, and the post-thaw sperm characteristics were evaluated. Treatment with 4-8% LDL during cooling and freezing significantly increased the intracellular cholesterol content, as compared to that of sperm frozen in extender containing 20% egg yolk (P<0.05). Higher potential resistance to cell damage from cryoinjury was also observed in sperm frozen in extender supplemented with LDL: the integrities of plasmalemma and DNA, mitochondrial activity and proteolytic activity of the acrosomal content in the post-thaw sperm were superior to those of sperm that were not treated with LDL. Moreover, the percentages of total motile sperm and the extent of rapid progressive motility at 1 and 3 h after incubation were markedly higher in sperm treated with 4 or 6% LDL, and these sperm also had more ATP. However, LDL did not inhibit in vitro sperm penetrability, even though the cholesterol content of post-thaw sperm was higher after treatment with LDL. These findings indicate that addition of 4-6% LDL instead of egg yolk to the freezing extender improves the post-thaw characteristics of Agu sperm by protecting sperm against cold shock damage during cryopreservation.
    Journal of Reproduction and Development 08/2009; 55(5):558-65. · 1.76 Impact Factor
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    ABSTRACT: The present study was conducted to determine whether vaginal electrical resistance (VER) can be exploited to improve the low reproductive efficiency of the rare Okinawan native Agu pig, in which estrous signs are difficult to ascertain by visual observation. The lowest VER (272.0+/-12.4 units, n=5) and the preovulatory LH surge were detected at 57.6+/-5.3 and 36.8+/-9.6h before the onset of estrus, respectively. The initiation of gradual increase in VER was found after 9.6+/-4.7h following the peak LH, and the higher levels of VER were plateaued during the luteal phase. These VER fluctuations were correlated with changes in plasma LH (P<0.05) and progesterone (P<0.001), but not estrogen. Moreover, the conception rate (41%, n=32) was dramatically improved by artificial insemination at 24 and 34 h after the beginning of the VER increase when compared with insemination at the conventional time (12 and 24h after detection of estrus, 20%, n=45), widely used in commercial pigs (P<0.05). These data suggest that VER fluctuation can be used to estimate the stage of the estrous cycle, and the scheduling artificial insemination according to increase in VER as an index for the preovulatory LH surge could improve Agu reproductive efficacy.
    Animal reproduction science 09/2008; 113(1-4):311-6. · 1.56 Impact Factor
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    ABSTRACT: The technical establishment of boar sperm cryopreservation is indispensable for effective breeding of the scarce Okinawan native pig Agu. The objective of the present study was to determine whether ascorbic acid 2-O-alpha-glucoside (AA-2G), a stable ascorbate derivative, is capable of improving the quality of cryopreserved Agu spermatozoa. Ejaculated Agu sperm frozen in an extender supplemented with 0, 100, 200, 400 or 800 microM AA-2G was thawed, and then evaluated the sperm motility and other qualities. Treatment with 200 microM AA-2G has the most beneficial effect on the sperm motility and the plasmalemma integrity after frozen-thawing among the concentrations tested (P<0.05). In particular, the incidences of total motile sperm and rapid progressive motility at 1 and 3h after incubation were markedly increased by treatment with AA-2G at 200 microM. The addition of AA-2G during cooling and freezing efficiently protected spermatozoa against the lipid peroxidation and the DNA damage. Spermatozoa frozen in the presence of AA-2G possessed significantly higher levels (P<0.05) of ATP even after thawing than those frozen without AA-2G, implying that sperm viability was effectively conserved. Furthermore, higher sperm penetrability to matured oocytes in vitro was maintained in sperm treated with AA-2G during cryopreservation. These effects were observed for all sperm derived from three individuals. These findings demonstrate that the addition of AA-2G to the freezing extender efficiently improves the post-thaw qualities of fragile Agu sperm through the protection of spermatozoa against cell damage caused by oxidative stress during cryopreservation.
    Cryobiology 05/2008; 57(1):30-6. · 2.14 Impact Factor
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    ABSTRACT: The present study was conducted to examine the effects of three tannin relatives (tannic acid, TA; gallic acid, GA; and ellagic acid, EA) on antihyaluronidase and reactive oxygen species (ROS) scavenging activity, in vitro fertilization (IVF) parameters, and the acrosome reaction (AR) induced by sperm-zona interaction. Among the three tannin relatives, TA and EA showed the strongest potency for blocking the hyaluronidase activity of boar sperm, with concentration-dependent inhibition over the range of 2-10 microg/ml. In contrast, ROSs were effectively scavenged by TA and GA, but not EA. When cumulus-free oocytes were inseminated in IVF medium containing 5 microg/ml of the tannin relatives, polyspermy was significantly reduced by TA and EA (32 and 29%, respectively) compared with oocytes treated with or without GA (51 and 69%, respectively) under conditions that maintained a high sperm penetration rate (P<0.05). Interestingly, induction of the AR by treatment of preincubated sperm with progesterone was blocked by TA and GA as a result of their higher levels of ROS scavenging activity, while EA, which possessed weak ROS scavenging activity, did not disturb induction of the AR with progesterone. However, the incidence of AR induced by sperm-zona interaction was significantly decreased by the strong antihyaluronidase actions of TA and EA compared with that in the absence of these compounds. Treatment with the compounds caused neither a protective proteolytic modification of the zona pellucida matrix before fertilization nor a reduction in acrosomal proteolytic activity or the number of zona-bound sperm. These findings suggest that the antihyaluronidase action of EA effectively prevents polyspermy by suppression of AR functionality induced by sperm-zona interaction and that hyaluronidase intervention is therefore required during porcine IVF.
    Journal of Reproduction and Development 08/2007; 53(4):755-64. · 1.76 Impact Factor
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    ABSTRACT: We previously reported that the anti-hyaluronidase agents oligosaccharide and tannic acid (TA) were efficient probes for promoting the normal fertilization process in terms of an effective decrease in the incidence of polyspermy, not only in cumulus-enclosed but also in denuded oocytes in pigs. It was unclear, however, why the polyspermic penetration into the zona pellucida (ZP) was directly prevented by the anti-hyaluronidase action. The present study was conducted to examine the effects of 3 tannin relatives [TA, gallic acid (GA), and ellagic acid (EA)] on IVF parameters and the acrosome reaction induced by the sperm–ZP interaction. The anti-hyaluronidase and radical-scavenging activities of tannin relatives were measured by the colorimetric and the DPPH methods, respectively. Porcine cumulus–oocyte complexes (COCs) were cultured for 44 h in 0.1 mL of TCM-199 supplemented with 0.6 mM cysteine, 40 mU mL-1 of FSH, 20 mU mL-1 of LH, and 10% porcine follicular fluid. After in vitro maturation (IVM), the COCs were freed from their cumulus cells and inseminated by frozen-thawed ejaculated sperm in modified Tris-buffered medium (IVF medium) containing 0 (control) or 5 µg mL-1 of tannin relatives. After 2 h of co-incubation, the oocytes were gently pipetted to remove loosely bound sperm and stained with Hoechst 33342 to count the number of ZP-bound sperm, or stained with fluorescein isothiocyanate (FITC)-PNA, PI, and 422,6-diamidino-2-phenylindole to evaluate the acrosomal status. At 10 h post-insemination, IVF parameters were examined by lacmoid staining. The data were analyzed by ANOVA and the Tukey-Kramer test. None of the tannin relatives caused a protective proteolytic modification of the ZP matrix or a reduction of the acrosomal proteolytic activity or the number of ZP-bound sperm. There was no difference in the sperm penetration rate even in the presence of tannin relatives (73-82%). However, the incidence of polyspermy was remarkably prevented by TA (32%; 31/98) and EA (21%; 20/94) compared with the control (58%; 58/100; P < 0.05), resulting from their strong anti-hyaluronidase actions, whereas GA without the anti-hyaluronidase action had no effect on the prevention of polyspermy (51%; 43/84). The rate of acrosome reaction induced by the sperm–ZP interaction was decreased by TA (15%; 123/833) and EA (16%; 110/708) compared with the control (25%; 238/939; P < 0.05), and a similar result was found in sperm binding to the pretreated ZP with 500 U of hyaluronidase for 2 h (18%; 351/1959). Interestingly, when sperm were incubated in IVF medium with 10 µg mL-1 of progesterone for 0.5 h to induce a compulsory acrosome reaction instead of the ZP, EA never disturbed the acrosome reaction (23%; 98/424) as control (23%; 102/437), although this reaction was blocked by TA (13%; 57/427) and GA (13%; 50/375), which possessed higher levels of radical-scavenging activity than EA (P < 0.05). These results indicate that the anti-hyaluronidase action of TA and EA effectively prevented polyspermy during porcine IVF as a consequence of suppression of the acrosome reaction functionally induced by the sperm–ZP interaction requiring the hyaluronidase intervention.
    Reproduction Fertility and Development - REPROD FERT DEVELOP. 01/2007; 19(1).
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    ABSTRACT: The objective of this study was to investigate the effects of estrogen receptor (ER) agonists and an ER antagonist on the expression of Hedgehog genes (Indian hedgehog: Ihh; Desert hedgehog: Dhh) and Hedgehog target genes (Patched 1: Ptc1; glioma-associated oncogene homolog 1: Gli1; chicken ovalbumin upstream promoter transcription factor II: Coup-TfII) in the rat uterus. Immature female rats were administered once with 17alpha-ethynyl estradiol (EE, an ER agonist), propyl pyrazole triole (PPT, an ERalpha-selective agonist), diarylpropionitrile (DPN, an ERbeta-selective agonist), or ICI 182,780 (an ER antagonist). Expression of mRNA for Ihh, Dhh, and Ptc1 was dose-dependently downregulated by EE in the uterus of immature rats, mediated by ER as confirmed by coadministration of ICI 182,780. The mRNA expression levels of Ptc1, Gli1, and Coup-TfII were simultaneously downregulated during the period in which the mRNA expression levels of Ihh and Dhh were downregulated in the uterus after administration of EE. PPT downregulated the transcription of Ihh, Dhh, Ptc1, Gli1, and Coup-TfII, indicating that expression of these genes was regulated by the ERalpha-dependent pathway. DPN also downregulated the transcription of Ihh and Dhh, although the effect was weaker than that of PPT, indicating that the regulation of uterine Ihh and Dhh transcription was also affected by the ERbeta-dependent pathway. These results suggest that the expression of Hedgehog genes (Ihh, Dhh) and Hedgehog target genes (Ptc1, Gli1, Coup-TfII) is affected by estrogenic stimuli in the uterus of immature female rats.
    Toxicology and Applied Pharmacology 01/2007; 217(3):375-83. · 3.98 Impact Factor
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    ABSTRACT: Two experiments were carried out on a laboratory scale. The first involved a study of the effect of green tea on characteristics of fermented juice of epiphytic lactic acid bacteria (FJLB). FJLB was treated with 50 g/L of green tea products as follows: new shoot powder (FJLB+N), leaf powder (FJLB+L), commercial powder (FJLB+P), sterilized new shoot powder (FJLB+SN), sterilized leaf powder (FJLB+SL) or sterilized commercial powder (FJLB+SP). FJLB without any additive was also prepared (Untreated FJLB). After incubation, the number of microorganisms in FJLB were studied. Subsequently, these FJLB were applied at 10 ml/kg to chopped rhodesgrass to study their effects on fermentation. Compared with untreated FJLB, the addition of green tea increased (p
    Asian Australasian Journal of Animal Sciences 01/2007; 20(6). · 0.64 Impact Factor
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    ABSTRACT: The present study was conducted to examine the effects of three polyphenols (tannic acid, apigenin and quercetin) on hyaluronidase activity and in vitro fertilization (IVF) parameters. Among them, tannic acid showed by far the strongest potency for blocking hyaluronidase activity extracted from preincubated boar sperm, causing a dose-dependent inhibition over the range of 2-10 microg/ml. When cumulus-intact and cumulus-free oocytes were inseminated in IVF medium containing tannic acid, the penetration and the polyspermy rates were significantly decreased in the presence of 10 microg/ml tannic acid compared with those in the absence of tannic acid, and the addition of 5 microg/ml tannic acid significantly reduced the polyspermy rate (p < 0.05) compared with that of the control while maintaining the high penetration rate. However, apigenin and quercetin had no effect on the rate of polyspermy. Interestingly, the incidence of polyspermy was significantly reduced in oocytes inseminated with sperm pretreated with 5 microg/ml tannic acid (p < 0.05), although the pretreatment of oocytes had no effect against the polyspermy after insemination with untreated sperm. Treatment with tannic acid caused neither a protective proteolytic modification of the zona pellucida matrix before fertilization, nor a reduction of the proteolytic activity of acrosomal contents or the number of zona-bound spermatozoa. These data suggest that an appropriate concentration of tannic acid prevents polyspermy through the inhibition of sperm hyaluronidase activity during IVF of porcine oocytes.
    Zygote 11/2006; 14(4):275-85. · 1.50 Impact Factor
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    ABSTRACT: To characterize the effects of an estrogen receptor (ER) agonist on the gene expressions in the uterus, immature female rats were administered once orally with 17alpha-ethynyl estradiol (EE, 3 mug/kg), a potent ER agonist. We focused on four categories of sex steroid hormone receptor genes: well-known estrogen target genes, Wnt genes, and beta-catenin/T-cell factor (TCF) target genes. ERalpha, ERbeta, progesterone receptor, and androgen receptor mRNAs were all downregulated at 24 and/or 48 h after EE administration. Complement C3 and insulin-like growth factor 1 mRNAs were markedly induced after EE administration. Although the time courses of Wnt4, Wnt5a, and Wnt7a mRNA status varied until 12 h after EE administration, all of them were simultaneously downregulated at 24 and 48 h. The remarkable downregulation of Wnt7a mRNA in response to EE was considered to be important to understand the various uterine phenomena affected by ER agonists. In the beta-catenin/TCF target genes, the downregulation of anti-Mullerian hormone type 2 receptor and bone morphogenetic protein 4 mRNA after EE administration appeared to be closely related to the downregulation of Wnt7a. The upregulation of cyclin D1 and follistatin mRNA at the early phase after EE administration was considered to have been affected by the upregulation of Wnt4. These results indicate that an ER agonist influences not only the mRNA expression of sex steroid hormone receptor genes and well-known estrogen target genes but also Wnt genes (Wnt4, Wnt5a, Wnt7a) and beta-catenin/TCF target genes in the uterus of immature rats, indicating that their molecules are the potential players affected by estrogenic stimuli.
    Toxicological Sciences 07/2006; 91(2):419-30. · 4.33 Impact Factor
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    ABSTRACT: A fermented juice from macerated napiergrass containing epiphytic lactic bacteria (FJLB) and napiergrass was prepared, mixed with defatted rice bran (FJLB + DRB) or dried green tea waste (FJLB + DTW) and freeze-dried. Silage was treated with FJLB + DRB, FJLB + DTW, DRB or DTW in powder form at levels of 2, 10 and 50 g kg−1 fresh matter (FM). FJLB in liquid form was added at a level of 10 mL kg−1 FM. All treated silages were well preserved, with lower pH, acetic acid and NH3-N content and higher lactic acid content than that of the control. Butyric acid was present only in the control silage and those treated with DRB or DTW. Without powdered FJLB additives, napiergrass silages had higher pH values, butyric acid and NH3-N content, but low lactic acid content compared with powdered FJLB silages. Increasing the amount of all powdered additives had effect on lactic acid and NH3-N content. It may thus be concluded that the powder form of FJLB was as effective in improving the fermentative quality of napiergrass as the liquid form. Copyright © 2006 Society of Chemical Industry
    Journal of the Science of Food and Agriculture 04/2006; 86(7):1073 - 1077. · 1.88 Impact Factor
  • Journal of Poultry Science - J POULT SCI. 01/2006; 43(3):307-311.
  • Journal of Poultry Science - J POULT SCI. 01/2006; 43(1):67-74.

Publication Stats

120 Citations
40.48 Total Impact Points

Institutions

  • 2013
    • Kagoshima University
      • Department of Science of Bioresource Production
      Kagosima, Kagoshima, Japan
  • 2004–2013
    • University of the Ryukyus
      • Faculty of Agriculture
      Okinawa, Okinawa-ken, Japan