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211.
Amitabha Bhattacharyya Eduardo R. S. Roldan Ryuzo Yanagimachi 《Molecular reproduction and development》1986,15(4):285-294
The majority of the spermatozoa precapacitated in Ca2+-free medium underwent the acrosome raction rapidly when they were transferred to Ca2+-containing medium. The presence of Na+ and Ca2+ in the medium was essential for the acrosome reaction. The vast majority of spermatozoa failed to undergo the reaction in Ca2+ medium lacking monovalent ions, although they remained motile. At the concentration of 140 mM, Na+, K+, Rb+, and Cs+ all supported the reaction at the maximum level, but at 50 mM the latter three ions were not as effective as Na+. Li+ was least effective in supporting the reaction. Virtually no acrosome reactions took place when precapacitated spermatozoa were first exposed to Na+ medium (no Ca2+) and then to Ca2+ medium (no Na+). On the other hand, a considerably higher proportion of spermatozoa acrosome reacted when they were exposed to these media in the reverse order. The most efficient acrosome reactions took place when the medium contained both a monovalent ion (Na+) and Ca2+ simultaneously. Possible mechanisms by which monovalent and divalent cations participate in the acrosome reaction are discussed. 相似文献
212.
Ryuzo Torii Hitoshi Koizumi Yoshikuni Tanioka Toshio Inaba Junichi Mori 《Primates; journal of primatology》1987,28(2):229-238
In the ovarian cycle of common marmosets, serum progesterone began to increase at two to three days after estradiol-17β or
LH surge, attained a peak of 25–70 ng/ml and then declined to a level of under 2 ng/ml before the ensuing rise in estradiol-17β
and LH. Serum estradiol-17β increased to 700–5,500 pg/ml during the luteal phase, synchronizing with progesterone. It is suggested
that the corpus luteum secreted estradiol-17β as well as progesterone. The cycle length as determined from the interval between
successive LH surges was approximately 28 days. During the luteal phase, the levels of progesterone and estradiol-17β were
higher than in Old World monkeys and women, but marmosets were not accompanied by any clinical symptoms due to excessive progesterone
and estradiol-17β. This suggests that such unresponsiveness to progesterone and estradiol-17β in marmosets reflects the small
amount of estradiol-17β receptor and presumably also the lower function of the post receptor system.
Recovery of the post-partum ovarian cycle in two marmosets differed from that observed in Old World monkeys and women. The
first LH surge was found on the ninth and tenth day after parturition and the first ovulation led to the next pregnancy. This
suggests that the suckling stimulus of newborns in the common marmoset does not cause any delay in recovery of the ovarian
cycle. In three cases of abortion, the recovery of the ovarian cycle was almost the same as that in the case of normal parturition:
the first LH surge appeared on the 10th, 14th, and 34th day after abortion. 相似文献
213.
We induced calluses from two Euphorbia species and analyzed the lipids and pigments of their cells. Growth was promoted when malt extract was added to the medium for callus induction. The lipid constituents of both E. tirucalli and E. millii calluses were the same; sitosterol, stigmasterol, campesterol, palmitic acid and linoleic acid. In addition, an anthocyanin, cyanidin glycoside, was isolated from callus that had been induced from E. millii leaves cultured on medium containing 0.1 ppm 2,4-d. 相似文献
214.
The effects of lipids on the survival, acrosome reaction, and fertilizing capacity of guinea pig spermatozoa were studied by incubating the spermatozoa in media containing various concentrations of the lipids. Lipids tested were: phosphatidyl-choline (PC), -ethanolamine (PE), -inositol (PI), -serine (PS), sphingomyelin (S), cholesterol (C), lysophosphatidyl-choline (LC), -ethanolamine (LE), -inositol (LI), -serine (LS), and glyceryl monooleate (M). When spermatozoa were incubated in a regular medium (containing 2 mM Ca2+) with M, the majority underwent the acrosome reaction within 1 hour. None of the other lipids were as effective as M, and some were totally ineffective under the same conditions. However, when spermatozoa were preincubated in Ca2+-free medium containing LC, LE, or LI, they gained the ability to undergo the acrosome reaction. One hour of preincubation in Ca2+-free medium with LC, LE, or LI was enough to render the vast majority of spermatozoa capable of undergoing the acrosome reaction in response to Ca2+. The optimum concentrations for LC, LE, and LI were approximately 85 μg/ml, 210 μg/ml, and 140 μg/ml, respectively. Spermatozoa that had undergone the acrosome reaction by pretreatment with LC, LE, or LI remained actively motile and were capable of fertilizing eggs. LS was totally ineffective in rendering the spermatozoa capable of undergoing the acrosome reaction, and in fact it inhibited the acrosome reaction by itself and also inhibited the LC-, LE-, or LI-mediated acrosome reaction. LS did not prevent acrosome-reacted spermatozoa from penetrating the zona pellucida, but did prevent sperm-egg fusion. Based on these findings, it is suggested that lysophospholipids are intricately involved in the sperm acrosome reaction and perhaps in sperm-egg fusion. 相似文献
215.
216.
Ryuzo Yanagimachi Gary N. Cherr Muralidharan C. Pillai John D. Baldwin 《Development, growth & differentiation》1992,34(4):447-461
When the micropyle area of salmonid (trout and salmon) eggs was observed continuously from the moment of insemination, spermatozoa were seen moving along the surface of the chorion and entering the micropyle one by one in a directed fashion. The ability of spermatozoa to enter the micropyle was reduced after the treatment of chorions with pronase; this reduction in sperm entry was observed even before the outer opening of the micropyle channel was narrowed due to gradual swelling of the chorion by pronase treatment. Herring spermatozoa, unlike spermatozoa of most other marine fishes, were motionless in seawater. However, they became vigorously motile on contact with the micropyle area of the herring egg chorion and entered the micropyle rapidly and efficiently. Motility initiation of herring spermatozoa in the micropyle area was dependent on extracellular calcium and potassium. Sodium also appears to be intricately involved in this process as demonstrated by the initiation of sperm movement in sodium-free seawater. When herring eggs were treated with acidic seawater, organic solvents, or glutaraldehyde, spermatozoa did not initiate movement in the micropyle area, and sperm entry was not observed. Herring spermatozoa did not initiate movement in the micropyle area of salmonid eggs. These and other observations suggest that the micropyle areas of salmonid and herring eggs possess some sperm guidance factors which facilitate entry of homologous spermatozoa into the micropyle. 相似文献
217.
Takahashi Masakazu Moriguchi Shigeo Minami Toshiko Suganuma Hiroyuki Shiota Akira Takenaka Yasuyuki Tani Fumito Sasaki Ryuzo Yoshikawa Masaaki 《International journal of peptide research and therapeutics》1998,5(1):29-35
Summary Albutensin A is an ileum-contracting peptide derived from serum albumin. The sequences of bovine, human and porcine albutensin
A are ALKAWSVAR, AFKAWAVAR, and AFKAWSLAR, respectively. These albutensin A homologs all exhibited biphasic ileal contractions
in the longitudinal strips of guinea pig ileum. The order of potency in the contraction was porcine>bovine>human homologs.
The ileal contraction profiles were similar to those of oryzatensin and casoxin C, agonist peptides for complement C3a receptors
derived from rice albumin and bovine κ-casein, respectively. All three homologs of albutensin A have homology with the COOH-terminal
sequences of complements C3a and C5a, which are essential for their activities; porcine albutensin A showed the highest homology.
Indeed, porcine albutensin A was confirmed to act through both C3a and C5a receptors by a radioreceptor assay and cross-desensitization
in the ileal contraction. In addition, bovine and human homologs also showed affinity for both receptors. This study suggests
that a bioactive peptide acting through both C3a and C5a receptors is released by the proteolytic cleavage of serum proteins
other than complement components. 相似文献
218.
Takayoshi Suzuki Keiko Imai Erika Imai Shinsuke Iida Ryuzo Ueda Hiroki Tsumoto Hidehiko Nakagawa Naoki Miyata 《Bioorganic & medicinal chemistry》2009,17(16):5900-5905
A series of 2-anilinobenzamide derivatives were designed, synthesized and evaluated for their SIRT1-inhibitory activity. Among these, compounds 3 and 5 inhibited SIRT1 activity in enzyme assays and suppressed the growth of Daudi and HCT116 cells. 相似文献
219.
Cherr GN Morisawa M Vines CA Yoshida K Smith EH Matsubara T Pillai MC Griffin FJ Yanagimachi R 《The International journal of developmental biology》2008,52(5-6):743-752
Sperm of the Pacific herring are immotile at spawning. Two egg-derived molecules are capable of initiating sperm motility. One is herring sperm activating protein(s) (HSAPs) and the other is sperm motility initiation factor (SMIF). These two motility initiators differ in their location and association with the chorion, and in thier isoelectric points and molecular weights. In this study we have investigated the roles of these two inducers with respect to motility and fertilization. Using computer analysis of sperm motility, we found that HSAPs, as well as the C-terminal HSAPs peptide, elicit a linear motility pattern, while SMIF induced a highly circular and asymmetric pattern. HSAPs induced a two-fold increase in intracellular calcium, whereas SMIF induced a four-fold increase of motility initiation. SMIF-exposed sperm, preloaded with BAPTA-AM, showed a more linear motility and this motility trajectory decreased with their fertilizing capability. The difference in intracellular calcium levels between HSAPs and SMIF is consistent with the observed linear and circular motility. In the absence of SMIF, HSAPs do not support fertilization. Fertilization is rescued in these experiments if SMIF is reintroduced. We propose that diffusible HSAPs are not essential for fertilization, but enhance sperm-egg collisions via linear motility. SMIF, which is bound to the micropylar region of the chorion, is required for fertilization and induces circular motility that is a prerequisite for sperm to enter the micropylar canal and fertilize the egg. 相似文献
220.
Birth of mice after intracytoplasmic injection of single purified sperm nuclei and detection of messenger RNAs and MicroRNAs in the sperm nuclei 总被引:1,自引:0,他引:1
We have developed a method that effectively removes all of the perinuclear materials of a mouse sperm head, including the acrosome, plasma membrane, perinuclear theca, and nuclear envelope. By injection of a single purified sperm head into a metaphase II mouse oocyte followed by activation with strontium chloride, 93% of the zygotes developed into two-cell embryos. Although only approximately 17% of the transferred two-cell embryos were born alive, all live pups developed into adults, and they appeared to be normal in reproduction and behavior. We detected RNA species, including mRNAs and miRNAs from the purified sperm heads. Our data demonstrate that pure membrane-free sperm heads are sufficient to produce normal offspring through intracytoplasmic sperm injection and that at least part of the RNA molecules are deeply embedded in the sperm nucleus. 相似文献