scholarly journals The effect of permeant and impermeant osmoticants on exocytosis in guinea pig sperm

1991 ◽  
Vol 100 (4) ◽  
pp. 761-769
Author(s):  
D.P. Green
Keyword(s):  
Electron Microscopy ◽  
Guinea Pig ◽  
Membrane Fusion ◽  
Acrosome Reaction ◽  
Ammonium Acetate ◽  
Ammonium Acetate Solution ◽  
Acetate Solution ◽  
Normal Medium ◽  
Acrosomal Membrane ◽  
External Calcium

Guinea pig sperm were suspended in calcium-containing medium supplemented with various concentrations of the tetrasaccharide, stachyose. At concentrations up to and including 0.6 M, stachyose was without effect on the A23187-induced acrosome reaction. At 1.0 M stachyose, greater than 97% of sperm retained their acrosome after exposure to A23187, as judged by light microscopy. Electron microscopy demonstrated, however, that exocytotic membrane fusion had occurred, although with substantial retention of the acrosomal matrix. Sperm incubated in 1.0 M stachyose solutions also underwent exocytotic membrane fusion in the absence of A23187 and external calcium. Sperm suspended in 0.175 M ammonium chloride solution progressively lost motility over 30 min, but without acrosomal swelling. By contrast, sperm in 0.19 M ammonium acetate underwent substantial swelling of the acrosome within 2–5 min. 70–80% of these sperm were able to exclude the vital dye propidium iodide with their acrosomes swollen. These sperm underwent acrosomal shrinkage if resuspended in normal medium within 5–10 min, and the majority (60–70%) recovered some motility. These sperm could undergo an A23187-induced acrosome reaction. Electron microscopy indicated that swelling in ammonium acetate solution solubilizes much of the acrosomal matrix and causes internal fusion between adjacent regions of the outer acrosomal membrane. There was no exocytotic membrane fusion in ammonium acetate solution, however. The evidence suggests that there is no stachyose osmolality for guinea pig sperm which will suppress the membrane fusion associated with exocytosis, and that sufficiently high osmolalities cause exocytotic membrane fusion in the absence of calcium.(ABSTRACT TRUNCATED AT 250 WORDS)

The histochemical localization of acrosin in guinea-pig sperm after the acrosome reaction

1978 ◽  
Vol 32 (1) ◽  
pp. 177-184
Author(s):  
D.P. Green ◽  
A.R. Hockaday
Keyword(s):  
Electron Microscopy ◽  
Guinea Pig ◽  
Acrosome Reaction ◽  
Sperm Head ◽  
Ultrastructural Evidence ◽  
Acrosomal Membrane ◽  
Sperm Penetration ◽  
Inner Acrosomal Membrane ◽  
Dense Marker

The protease acrosin is widely considered to be an essential component of a zona lysin which enables sperm to penetrate the zona pellucida of the egg. Sperm form a characteristic penetration slit little wider than the sperm head itself and this has long suggested that any zona lysin is attached to the sperm surface after an acrosome reaction. This paper provides the first ultrastructural evidence that this is the case. The protein acrosin inhibitor, Kunitz soybean trypsin inhibitor, has been covalently attached to the electron-dense marker, ferritin, and the conjugate incubated with guinea-pig sperm which have undergone an A23187-induced acrosome reaction. Electron microscopy shows that ferritin is distributed unevenly over the outer surface of the newly exposed inner acrosomal membrane but does not extend to the equatorial segment. This is further evidence that acrosin can be considered as a candidate for the role of zona lysin. The mechanism of sperm penetration of the zona is discussed in the light of these observations.

scholarly journals Sodium requirement for capacitation and membrane fusion during the guinea-pig sperm acrosome reaction

Reproduction ◽  
1984 ◽  
Vol 70 (1) ◽  
pp. 83-94 ◽  
Author(s):  
R. V. Hyne ◽  
R. E. Higginson ◽  
D. Kohlman ◽  
A. Lopata
Keyword(s):  
Guinea Pig ◽  
Membrane Fusion ◽  
Acrosome Reaction ◽  
Sperm Acrosome Reaction ◽  
Sperm Acrosome

The induction of the acrosome reaction in guinea-pig sperm by the divalent metal cation ionophore A23187

1978 ◽  
Vol 32 (1) ◽  
pp. 137-151
Author(s):  
D.P. Green
Keyword(s):  
Guinea Pig ◽  
Metal Cation ◽  
Acrosome Reaction ◽  
Divalent Metal ◽  
Secretory Cells ◽  
Free Calcium ◽  
Ionophore A23187 ◽  
Divalent Metal Cation ◽  
Free Calcium Concentration ◽  
External Calcium

The divalent metal cation ionophore A23187 induces an acrosome reaction in guinea-pig sperm which is dependent on external calcium. Examination of this acrosome reaction by electron microscopy shows that it is morphologically normal. The known properties of A23187 and the morphological similarity between the acrosome reaction and the secretory discharges of other secretory cells suggests that the immediate cause of the acrosome reaction is an increase in the cytoplasmic free calcium concentration.

scholarly journals Membrane particle changes attending the acrosome reaction in guinea pig spermatozoa

1977 ◽  
Vol 74 (2) ◽  
pp. 561-577 ◽  
Author(s):  
DS Friend ◽  
L Orci ◽  
A Perrelet ◽  
R Yanagimachi
Keyword(s):  
Plasma Membrane ◽  
Guinea Pig ◽  
Acrosome Reaction ◽  
Plasma Membranes ◽  
Freeze Fracture ◽  
Phosphatidylcholine Liposomes ◽  
Acrosomal Membrane ◽  
Large Particles ◽  
Fracture Appearance ◽  
Preparatory Stage

To examine the freeze-fracture appearance of membrane alterations accompanying the preparation of sperm membranes for fusions-the first preparatory stage occurring before physiological release of the acrosomal content, the second afterward-we induced the acrosome reaction in capacitated guinea pig spermatozoa by adding calcium to the mixture. The most common features observed before fusion of the acrosomal and plasma membranes were the deletion of fibrillar intramembranous particles from the E-fracture faces of both membranes, and the clearance of globular particles from the P face of the plasma membrane-events taking place near the terminus of the equatorial segment. Large particles, >12nm, remained not far from the cleared E-face patches. The P face of the outer acrosomal membrane is virtually clear from the outset. In addition, when fusion was completed, occasional double lines of large particles transiently embossed the P face of the plasma membrane (postacrosomal) side of the fusion zone. Behind the line of fusion, another series of particle-cleared foci emerged. We interpreted these postfusion membrane clearances as a second adaptation for sperm-egg interaction. Induction of the acrosome reaction in media containing phosphatidylcholine liposomes resulted in their apparent attachment, incorporation, or exchange in both the originally and secondarily cleared regions. Our observations support the concepts that membranes become receptive to union at particle- deficient interfaces, and that the physiologically created barren areas in freeze-fracture replicas may herald incipient membrane fusion.

scholarly journals Analysis of Nicotine and Nicotine-Related Compounds in Electronic Cigarette Liquids and Aerosols by Liquid Chromatography-Tandem Mass Spectrometry

2017 ◽  
Vol 27 (7) ◽  
pp. 154-167 ◽  
Author(s):  
Xinyu Liu ◽  
Peter Joza ◽  
Bill Rickert
Keyword(s):  
Sample Preparation ◽  
Ammonium Acetate ◽  
Ammonium Bicarbonate ◽  
Ammonium Acetate Solution ◽  
Gradient System ◽  
Acetate Solution ◽  
Target Compound ◽  
Internal Standards ◽  
Phase Gradient ◽  
Related Compounds

Summary The objective of this study was to develop and validate an analytical method for determining nicotine and nicotine related compounds (i.e., nicotine-N-oxide, cotinine, nornicotine, anatabine, myosmine, anabasine, and β-nicotyrine) in e-cigarette aerosols and e-liquids. Aerosol collection was achieved using a Cambridge collection pad. The sample preparation consisted of adding deuterated internal standards to the collection pad and extracting with 100 mM ammonium acetate solution using a wrist-action shaker. The filtrate was then analyzed by LC-MS/MS using a Gemini NX C18 column (3 μm, 150 × 3 mm) with a mobile phase gradient system consisting of acetonitrile and 10% acetonitrile in 10 mM ammonium bicarbonate (pH = 8.0) and electrospray ionization (ESI) in the positive mode. The e-liquid was analyzed using the same instrumental parameters, but simplifying the sample preparation procedure by adding deuterated internal standards directly to the 100-mg sample. The sample was then extracted with 100 mM ammonium acetate solution, sonicated, and filtered. In this study, the method’s accuracy, robustness, and reliability were enhanced by using deuterated analogues of each compound as internal standards and by applying two ion-transition pairs for each compound for the confirmation and quantification. Validation experiments demonstrated good sensitivity, specificity and reproducibility. All the target compound calibrations exhibited satisfactory linearity from 0.050 to 5.0 mg/mL (r2 > 0.995). The average recoveries for e-liquids varied from 85.2% (nicotine-N-oxide) to 110% (β-nicotyrine) with recoveries for all compounds exhibiting a coefficient of variation (CV) < 5.0%. Similarly, the average recoveries for e-cigarette aerosols varied from 87.8% (for nicotine-N-oxide) to 111% (for myosmine) with all CV < 8.8%. The LOD and LOQ for e-liquids for all target compounds ranged from 0.234 and 0.781 μg/g (cotinine) to 1.66 and 5.48 μg/g (nicotine-Noxide). For e-cigarette aerosols these limits ranged from 0.094 and 0.312 μg/collection (cotinine) to 0.872 and 2.87 μg/collection (nicotine-N-oxide). This methodology was used to quantitatively determine if any of the target compounds were present in a variety of sample matrices, including e-cigarette solutions and aerosols, and was successfully applied to stability studies, to monitor changes in the target compound levels which might be caused by e-cigarette formulations, components and the storage conditions.

The Solubility of Lead Iodate in Ammonium Acetate Solution

1940 ◽  
Vol 62 (9) ◽  
pp. 2367-2369 ◽  
Author(s):  
Sylvan M. Edmonds ◽  
Nathan Birnbaum
Keyword(s):  
Ammonium Acetate ◽  
Ammonium Acetate Solution ◽  
Acetate Solution

Sorption of Metal Ions on an Anion-Exchange Resin in an Ammonium Acetate Solution

2020 ◽  
Vol 94 (6) ◽  
pp. 1190-1194
Author(s):  
N. A. Mirzaev ◽  
A. P. Marinova ◽  
Kh. F. Mammadov ◽  
N. T. Temerbulatova ◽  
J. Kozempel ◽  
...  
Keyword(s):  
Metal Ions ◽  
Anion Exchange ◽  
Ammonium Acetate ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Ammonium Acetate Solution ◽  
Acetate Solution

scholarly journals Localized surface antigens of guinea pig sperm migrate to new regions prior to fertilization.

1984 ◽  
Vol 99 (5) ◽  
pp. 1634-1641 ◽  
Author(s):  
D G Myles ◽  
P Primakoff
Keyword(s):  
Monoclonal Antibody ◽  
Cell Surface ◽  
Guinea Pig ◽  
Surface Antigen ◽  
Acrosome Reaction ◽  
Tail Region ◽  
Head Region ◽  
Surface Molecules ◽  
Acrosomal Membrane ◽  
Sperm Population

We have previously defined distinct localizations of antigens on the surface of the guinea pig sperm using monoclonal antibodies. In the present study we have demonstrated that these antigen localizations are dynamic and can be altered during changes in the functional state of the sperm. Before the sperm is capable of fertilizing the egg, it must undergo capacitation and an exocytic event, the acrosome reaction. Prior to capacitation, the antigen recognized by the monoclonal antibody, PT-1, was restricted to the posterior tail region (principle piece and end piece). After incubation in capacitating media at 37 degrees C for 1 h, 100% of the sperm population showed migration of the PT-1 antigen onto the anterior tail. This redistribution of surface antigen resulted from a migration of the surface molecules originally present on the posterior tail. It did not occur in the presence of metabolic poisons or when tail-beating was prevented. It was temperature-dependent, and did not require exogenous Ca2+. Since the PT-1 antigen is freely diffusing on the posterior tail before migration, the mechanism of redistribution could involve the alteration of a presumptive membrane barrier. In addition, we observed the redistribution of a second surface antigen after the acrosome reaction. The antigen recognized by the monoclonal antibody, PH-20, was localized exclusively in the posterior head region of acrosome-intact sperm. Within 7-10 min of induction of the acrosome reaction with Ca2+ and A23187, 90-100% of the acrosome-reacted sperm population no longer demonstrated binding of the PH-20 antibody on the posterior head, but showed binding instead on the inner acrosomal membrane. This redistribution of the PH-20 antigen also resulted from the migration of pre-existing surface molecules, but did not appear to require energy. The migration of PH-20 antigen was a selective process; other antigens localized to the posterior head region did not leave the posterior head after the acrosome reaction. These rearrangements of cell surface molecules may act to regulate cell surface function during fertilization.

Proteases are not involved in the membrane fusion events of the lysolecithin-mediated guinea pig sperm acrosome reaction

1993 ◽  
Vol 104 (1) ◽  
pp. 163-172
Author(s):  
S.P. Flaherty ◽  
N.J. Swann
Keyword(s):  
Guinea Pig ◽  
Membrane Fusion ◽  
Protease Inhibitors ◽  
Acrosome Reaction ◽  
Structural Pattern ◽  
Wide Range ◽  
Bean Trypsin Inhibitor ◽  
Specific Protease ◽  
Sperm Acrosome Reaction ◽  
Sperm Acrosome

The guinea pig sperm acrosome reaction is characterized by a complex temporal and structural pattern of membrane fusions. In this study, we have used specific protease inhibitors to determine if proteases regulate this pattern of membrane fusions during the lysolecithin-mediated guinea pig sperm acrosome reaction. Inhibitors were chosen so as to cover a wide range of different types of proteases, and all were used at the highest concentration that did not adversely affect sperm motility. Of the eight inhibitors tested, leupeptin, soya bean trypsin inhibitor (SBTI), p-aminobenzamidine (pAB) and nitrophenyl p'-guanidino benzoate (NPGB) inhibited completion of the acrosome reaction, while diethylenetriaminepentaacetic acid (DTPA), phosphoramidon, bestatin and pepstatin had no effect. Sperm that had been acrosome-reacted in the presence of each inhibitor were examined by transmission electron microscopy to assess whether the inhibitors altered the pattern of membrane fusions during the acrosome reaction. DTPA, phosphoramidon, bestatin and pepstatin had no effect on membrane fusion or matrix dispersal. Serine protease inhibitors such as leupeptin, SBTI, pAB and NPGB prevented complete dispersal of the acrosomal matrix and completion of the acrosome reaction, but did not alter the temporal sequence or structural pattern of membrane fusions. The undispersed matrix was present along the dorsal and ventral aspects of the apical segment and throughout the principal segment. We conclude that proteases are not involved in regulating the temporal and structural pattern of membrane fusions which occurs during the lysolecithin-mediated acrosome reaction of guinea pig sperm.

Aluminium, extractable from soil samples by the acid ammonium acetate soil-testing method

1968 ◽  
Vol 40 (2) ◽  
pp. 54-59
Author(s):  
Osmo Mäkitie
Keyword(s):  
Acetic Acid ◽  
Ammonium Acetate ◽  
Acid Soils ◽  
Soil Samples ◽  
Ammonium Acetate Solution ◽  
Soil Testing ◽  
Acetate Solution ◽  
Mean Values ◽  
Testing Method ◽  
The Mean

The extractant, 0.5 M acetic acid –0.5 M ammonium acetate at pH 4.65, which is used in soil-testing, extracts relatively high amounts of aluminium from acid soils. The mean values of acetate-extractable aluminium at pH 4.65, 1.75 meq Al/100 g of soil, and of exchangeable aluminium (M KCI extraction), 0.41 meq Al were obtained from a material of 30 samples of acid soils (Table 2). Several other acetic acid ammonium acetate extractants, from M acetic acid to M ammonium acetate solution were also used for studying the extractability of soil aluminium. The soil-testing extractant can be used for the estimation of the soluble amounts of aluminium in acid soils, however, further studies are needed for a better interpretation of the ammonium acetate extractable (at pH 4.65) aluminium in our soils.

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