摘要:

AbstractDemembranated spermatozoa of Ciona do not become motile when provided with MgATP, unless their motility is activated in vivo before demembranation or unless the demembranated spermatozoa are activated in vitro with cAMP or with the catalytic subunit of a cAMP‐dependent protein kinase. CAMP causes a greater than fivefold enhancement of32P incorporation by demembranated spermatozoa. Analysis by one‐dimensional PAGE and autoradiography shows several axonemal protein bands that become32P‐labeled during in vitro activation with cAMP and identifies protein bands whose labeling is specifically reduced if motility of the spermatozoa is activated before demembranation, suggesting that these proteins also become phosphorylated during activation of motolity in vivo. These phosphorylated proteins appear to include dynein heavy‐chain components, but axonemal tubulin is not phosphorylated. Partially phosphorylated spermatozoa can be activated by an increase in KCI concentration, which appears to dissociate one phosphorylated component from the

ISSN:0148-7280    

DOI:10.1002/mrd.1120080302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe postovulatory fertile life of mammalian eggs is remarkably short (approximately 6‐36h). Anomalies of embryogenesis may result from fertilization of aged, defective eggs. Attempts to study this problem using whole‐animal models are complicated by chances in the natural milieu of the gametes. In the present study, postovulatory hamster eggs were allowed to agein vivo then fertilized in vitro. Cumulus‐intact eggs recovered from superovulated hamsters either 2 or 9 h after the estiated time of ovulation (12 h postHCG) were incubated for 4 h with preincubated sperm suspentions in a modified Tyrode's solution devised for in vitro fertilization. Eggs were either fixed or cultured for another 20h in fresh medium to allow cleavage to occur, then examined by light microscopy (phase and interference‐contrast). No significant difference was found in the ablities of fresh and aged eggs to be penetrated by spermatozoa (94% vs 90%, respectively; 8 replicated experiments), but only 59% of penetrated aged eggs were found to undergo morphologically normally fertilization (2 polar bodies, 2 prounclei) compared with 75% of fresh eggs (difference significant, P<0.01). About 13% of eggs were polyspermic in both categories. The most common anomaly in aged fertilied egges was failure to extrude the second polor body (23% off eggs vs 8% of fresh eggs, P<0.01). Only 21% of aged eggs underwent first cleavaage, and only 74% of these appeared morphologically normal, compared with value of 68% and 98%, respectively, for fresh eggs. These data show that in the hamster, abnormal fertilization and cleavage failure can, in part, be directly attributed to postovulatory deterioration of eggs. We also infer that the apparently very short penetrable life of hamster eggs in vivo shown by previous investigators is an indirect effect of postovulatory changes in the female reproductive tract that are unfavorable for sperm‐egg int

ISSN:0148-7280    

DOI:10.1002/mrd.1120080303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe ultrastructure of the sperm head of the plains mouse, Pseudomys australis, and the effects of chemical treatments on the sperm head components has been investigated to determine the nature of the material in the hooks on the apical margine of the sperm head. Ultrastructural studies indicated that the dorsal hook contained nuclear, subacrosomal, and acrosomal material, whereas the two ventral hooks were largely composed of an extention of the subacrosomal material with two thin acrosomal projections at their base. Acrosomal material was dispersed by mild detergent treatment, where as the bulk of the material in the ventral hooks were generally found to be similar to the subacrosomal material in the dorsal hook in their resistance to the various chemical treatments. Treatment of sperm with NaOH or guanidine‐hydrochloride and DTT revealed two layers of material in the ventral hook

ISSN:0148-7280    

DOI:10.1002/mrd.1120080304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractXenopus laevis oocytes undergo maturation when they are injected with large quantities of crude ribosomes from various origins: X laevis full‐grown or matured oocytes, Xenopus ovaries and embryos, Xenopus liver or mouse liver. All have the same efficiency, whatever their origin: they include 50‐90% maturation in the injected oocytes at about the same speed as progesterone treatment. The ribosomal preparations are inactive wen injected into recipient oocytes pretreated with cholera toxin or cycloheximide. After dissociation with the high salt extract, but not with the subunits. Hypotheses concernning the mode action of this ribosomal extract are disus

ISSN:0148-7280    

DOI:10.1002/mrd.1120080305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractFluorescent antibody labeling techniques are frequently used to investigate the topography of antigens on spermatozoa. It is generally assumed that these procedures detect molecules only on the sperm surface but we now show that this assumption is not always valid. Using monoclonal antibodies that recognize either surface or internal antigens we demonstrate how spurious conclusions can be made, and we suggest simple procedures for assigning the position of an antigen to the cell surface or to an intracellular organelle. Antibodies against plasma membrane antigens should stain 100% of normal intact spermatozoa, but this proportion should be greatly reduced if the spermatozoa have previously been demembranated. If ≪ 100% of spermatozoa are stained but the proportion increases following permeabilization, then the possibility should be considered that the antigens are intracellular. We conclude that assignment of an antigen to a regional domain on the sperm surface using fluorescent antibody techniques should be validated by a demonstration that the antigen is actually located on the cell surfac

ISSN:0148-7280    

DOI:10.1002/mrd.1120080306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractNucleolar ultrastrure was studied in fully grown human oocytes obtained from multilaminar preantral follicles and from follicles at different stages of antrum formation. Selective staining for ribonucleoproteins and3H‐uridine labeling were used in attempt to better understand the nature and functional significance of homogeneous dense nucleoli found in oocytes from large antral follicles.There was an apparent increase in the radio of nucleonema to nucleolar interstices, accompanied by a gradual degranulation of the nucleolonema during early stages of antrum fromation. The process of nucleolar homogenization continued in oocytes from medium‐size antralfollicles, island of more tightly packed fibrils being hybothesized to represent persisting active transcription units. Entirely filamentous and homogeneous nucleoli were typical for oocytes from large antral follicles. They were demonstrated to ribonucleoprotein filaments embedded in pale‐ staining matrix. They were demonstrated to contain newly synthesized RNA after a 30‐min pulse with3H‐uridine. The described nucleolar transformations are interpreted as acorrelate of nucleolar transition from a site of RNA synthesis into a site of RNA Storage during in human oocyte preovulatory de

ISSN:0148-7280    

DOI:10.1002/mrd.1120080307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractA species‐specific factor capable of disersing the jelly coat surrounding eggs has been purified from sperm of the sea urchin, Anthocidaris crassisina. It does not exert its effect on the vitelline layer. The purification has been accomlished by a four‐step procedure involving ammonium sulfate fractionation, gel filtration on Sepharose CL‐4B, ion‐exchange column chromatography on DEAE‐cellulose, and affinity column chromatograhy on heparin‐Seharose CL‐6B. The isolated factor is homogenous in sodium dodecyl sulfate polyacrylamide gel electrohoresis in the presence or absence of β‐mercatoethanol, estimated molecular weight being about 140,000.The jelly dispersion by the present factor is activated by CaCl2, and inhibited by KCl, MnCl2, EDTA, and EGTA, and by sulfated saccharides such as chondroitin sulfate A and C, heparin, and glucose‐6‐sulfate, Inorganic sulfated such as (NH4)2SO4and Na2SO4have no effect on jelly dispersion. This factor is heat‐labile, its activity in 30 min at 50°C.The present factor is found also in the seminal Plasma, and released from sperm themselves by treatment with Triton X‐100 .These results suggest that this factor is loosely bound to the serm surface. Although glycosidase and arylsulfatase activities are detectable in the seminal plasma, these enzyme activities are not detectable in the purified jelly disersing factor.Only trypsin and α chymotrysin among commercial enzymes tested dispersing activity is inhibited neither by trypsin inhibitors such as N‐α‐p‐tosyl‐L‐lysine‐chloromethyl ketone, soybean trypsin inhibitor, ovomucoid trypsin inhibitor, nor by chymotrypsin inhibitors such as L‐1‐tosylamide‐2 pheny‐ethylcholoromethyl ketone and chymostatin Participation of trysin‐like and chymotrypsi

ISSN:0148-7280    

DOI:10.1002/mrd.1120080308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe ascidian sperm reaction, Which involves swelling, migration, and loss of the single large mitochondrion, can be triggered in vitro by raising the seawater pH to 9.3 or lowering Na+to 20 mM, but only if the sperm are allowed to attach to a suitable Substate. Mitochondrial translocation does not usually occur in the absence of sperm attachment. Extracellular Ca2+is necessary for triggering the reaction with low Na+but not high pH; however, the intrecellular Ca2+blocker, TMB‐8, inhibits high pH‐induced mitochondrial movement in the absence of extracellular Ca2+. After swelling, the mitochondrion fluoresces in the presence of chlortetracycline, suggesting that Ca2+becomes membranebound after activation. Elevated cAMP and theophylline both inhibit mitochondrial move ment but not sperm motility. The antiactin drug cytochalasin B(10μM) and the calmodulinblocking drugs TFP (1 μM) and W‐13 (10 μM) block mitochondrial movement, suggesting roles for actin and calmodulin in mitochondrial movement. A model is proposed relating intracellular alkalinization, Ca2+influx, actin, myosin, and calmodulin in mitochondrial trans

ISSN:0148-7280    

DOI:10.1002/mrd.1120080309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

ISSN:0148-7280    

DOI:10.1002/mrd.1120080301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY