Cryopreservation alters the Ca2+ flux of bovine spermatozoa

1994 ◽  
Vol 74 (1) ◽  
pp. 45-51 ◽  
Author(s):  
J. L. Bailey ◽  
M. M. Buhr
Keyword(s):  
Key Words ◽  
Acrosome Reaction ◽  
Intracellular Ca ◽  
Bovine Spermatozoa ◽  
Free Media ◽  
Cellular Ca ◽  
Over Time

Capacitation and the acrosome reaction are Ca2+-dependent events that must be properly timed for successful fertilization to occur. To test the hypothesis that the cryopreservation procedures alter the ability of bovine spermatozoa to regulate Ca2+, the ability of Percoll-washed fresh and cryopreserved spermatozoa obtained from the same ejaculate (four ejaculates from each of six bulls) to regulate Ca2+ over time was monitored using the fluorescent Ca2+ chelator indo-1. The ability of spermatozoa to control Ca2+ levels varied among ejaculates from a bull, and among bulls; these effects were statistically accounted for in the analysis of the effects of cryopreservation. Initially, cryopreserved spermatozoa had lower viability, motility, and normal acrosome scores and more intra- and extra-cellular Ca2+ than fresh spermatozoa. Intra- and extra-cellular Ca2+ was monitored for 150 min, with 1 mM exogenous Ca2+ or buffer being added at 30 min to the spermatozoa being used to monitor intracellular Ca2+. By 30 min, extracellular Ca2+ was higher for fresh cells and then remained constant. Intracellular Ca2+ of fresh and cryopreserved spermatozoa in Ca2+-free media slowly increased. While both fresh and cryopreserved cells in Ca2+-supplemented media accumulated Ca2+ more rapidly, cryopreserved spermatozoa did so faster than fresh. Post-experimental viability was lower in cryopreserved spermatozoa that had been exposed to exogenous Ca2+. In conclusion, cryopreservation affects initial intra- and extra-cellular Ca2+ levels of bovine spermatozoa, and their ability to control subsequent rates of Ca2+ accumulation. Key words: Bovine, cryopreservation, calcium, indo–1, spermatozoa

Ca Entry and Contraction as Studied in Isolated Bovine Ventricular Myocytes

1982 ◽  
Vol 37 (5-6) ◽  
pp. 502-512 ◽  
Author(s):  
Gerrit Isenberg
Keyword(s):  
Time Course ◽  
Ventricular Myocytes ◽  
Voltage Step ◽  
Exponential Time ◽  
Intracellular Ca ◽  
Ca Inward Current ◽  
Contraction And Relaxation ◽  
Free Media ◽  
The Relationship ◽  
Cellular Ca

Abstract Single bovine ventricular myocytes were superfused with Tyrode solution containing 1.8 mᴍ CaCl2. The cells did not bear external load and contracted isotonically. Contraction and relaxation were characterized by the shortening and relengthening of the sarcomeres which resembled in their time course the isometric twitches of bovine papillary muscles. Resemblance was also found in regard to positive inotropic interventions as increase in the stimulation frequency, exposure to elevated [Ca]0 or to adrenaline. A two-microelectrode voltage-clamp technique was applied to the single myocyte. The trans­membrane Ca inward current ICa was defined as difference current sensitive to 5 mᴍ Ni or to 2 μᴍ D600. During a voltage step from -45 to + 5 mV, ICa peaked within 3 ms to -6 nA, afterwards it decayed to 15% of peak amplitude (incomplete inactivation with a 2 exponential time course). Experiments in Na-free media suggested that Na entry does not significantly contaminate ICa. Therefore, Ca entry could be calculated from ICa. The increment in total intra­ cellular Ca concentration (Δ[Ca]iT) was estimated by referring Ca entry to the cell volume (50 pl). Within 100 ms Δ[Ca]iT came to 25 μᴍ at control conditions, to 55 μᴍ at [Ca]0 = 3.6 mᴍ and to 88 μᴍ when 0.1 μᴍ adrenaline were present. The Δ[Ca]iT values were sufficient to activate contraction without the necessity of Ca-release from SR.Despite the new data, the relationship between Ca entry and activation of contraction was complex: during the “positive Herztreppe” ICa slightly attenuated but contractility doubled. Therefore, the old EC-model (M. Morad and Y. Goldman, Progr. Biophys. Mol. Biol. 27, 257 (1973)) was adapted. The Ca-entry’s capability to load and to overload the intracellular Ca store (SR) is discussed.

scholarly journals Ca2+-stores in sperm: their identities and functions

Reproduction ◽  
2009 ◽  
Vol 138 (3) ◽  
pp. 425-437 ◽  
Author(s):  
Sarah Costello ◽  
Francesco Michelangeli ◽  
Katherine Nash ◽  
Linda Lefievre ◽  
Jennifer Morris ◽  
...  
Keyword(s):  
Acrosome Reaction ◽  
Somatic Cells ◽  
Functional Interaction ◽  
Mammalian Sperm ◽  
Intracellular Ca ◽  
Principal Piece ◽  
Oscillations And Waves ◽  
Molecular Components ◽  
Cellular Ca ◽  
Discrete Functions

Intracellular Ca2+stores play a central role in the regulation of cellular [Ca2+]iand the generation of complex [Ca2+] signals such as oscillations and waves. Ca2+signalling is of particular significance in sperm cells, where it is a central regulator in many key activities (including capacitation, hyperactivation, chemotaxis and acrosome reaction) yet mature sperm lack endoplasmic reticulum and several other organelles that serve as Ca2+stores in somatic cells. Here, we review i) the evidence for the expression in sperm of the molecular components (pumps and channels) which are functionally significant in the activity of Ca2+stores of somatic cells and ii) the evidence for the existence of functional Ca2+stores in sperm. This evidence supports the existence of at least two storage organelles in mammalian sperm, one in the acrosomal region and another in the region of the sperm neck and midpiece. We then go on to discuss the probable identity of these organelles and their discrete functions: regulation by the acrosome of its own secretion and regulation by membranous organelles at the sperm neck (and possibly by the mitochondria) of flagellar activity and hyperactivation. Finally, we consider the ability of the sperm discretely to control mobilisation of these stores and the functional interaction of stored Ca2+at the sperm neck/midpiece with CatSper channels in the principal piece in regulation of the activities of mammalian sperm.

scholarly journals Metabolic control of daily locomotor activity mediated by tachykinin in Drosophila

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sang Hyuk Lee ◽  
Eunjoo Cho ◽  
Sung-Eun Yoon ◽  
Youngjoon Kim ◽  
Eun Young Kim
Keyword(s):  
Locomotor Behavior ◽  
Sensory Inputs ◽  
Sucrose Diet ◽  
High Nutrient ◽  
Intracellular Ca ◽  
High Sucrose Diet ◽  
Locomotor Activities ◽  
Locomotor Behaviors ◽  
High Sucrose ◽  
Over Time

AbstractMetabolism influences locomotor behaviors, but the understanding of neural curcuit control for that is limited. Under standard light-dark cycles, Drosophila exhibits bimodal morning (M) and evening (E) locomotor activities that are controlled by clock neurons. Here, we showed that a high-nutrient diet progressively extended M activity but not E activity. Drosophila tachykinin (DTk) and Tachykinin-like receptor at 86C (TkR86C)-mediated signaling was required for the extension of M activity. DTk neurons were anatomically and functionally connected to the posterior dorsal neuron 1s (DN1ps) in the clock neuronal network. The activation of DTk neurons reduced intracellular Ca2+ levels in DN1ps suggesting an inhibitory connection. The contacts between DN1ps and DTk neurons increased gradually over time in flies fed a high-sucrose diet, consistent with the locomotor behavior. DN1ps have been implicated in integrating environmental sensory inputs (e.g., light and temperature) to control daily locomotor behavior. This study revealed that DN1ps also coordinated nutrient information through DTk signaling to shape daily locomotor behavior.

Slangs as a Special Group of Words

2020 ◽  
Vol 60 (11) ◽  
pp. 103-107
Author(s):  
Mehriban Zeynal Hajizade ◽  
Keyword(s):  
Key Words ◽  
Native Speakers ◽  
Social Groups ◽  
Main Function ◽  
Special Group ◽  
Modern Times ◽  
The World ◽  
Normative Status ◽  
Over Time

In modern times, the processes in the world have affected the field of linguistics as well as all other fields.These processes require a diffferent approach to issues related to the use of specific word groups. Over time, language develops and changes occur at all levels. Taking into consideration that the main function of language is a means of communication between people, all changes should be taken into account to make the function more convenient and more suitable. Some of the processes that take place in the language are directly related to the speech process, and ends with getting the gradual normative status of variants in the speech of native speakers. Native speakers use some expressions that gained and didn’t gain status of norms in their speech. They use specific word groups to make their speech more specific and expressive. These word groups are used by some groups of people for special goals. Slangs are new meaningful words used in different social groups. Slangs are presented as non-literary concept. Slangs are various and colorful according to their tones. Key words: slang, morphem, term, communication, society

scholarly journals Asterosap, an Egg Jelly Peptide, Elevate Intracellular Ca2+ and Activate the Motility of Spermatozoa

2013 ◽  
Vol 19 (1) ◽  
pp. 79-88 ◽  
Author(s):  
MS Islam ◽  
T Akhter ◽  
M Matsumoto
Keyword(s):  
Plasma Membrane ◽  
Cyclic Gmp ◽  
Guanylyl Cyclase ◽  
Acrosome Reaction ◽  
Nickel Chloride ◽  
Selective Inhibitor ◽  
Ion Flux ◽  
Intracellular Ca ◽  
A Cell ◽  
Egg Jelly

Components from the outer envelopes of the egg that influence the flagellar beating and acrosome reaction of spermatozoa are regulated by ion flux across the plasma membrane. Asterosap, a sperm-activating peptide from the starfish egg jelly layer, causes a transient increase in intracellular cyclic GMP (cGMP) through the activation of the asterosap receptor, a guanylyl cyclase (GC), and causes an increase in intracellular Ca2+. Here we describe the pathway of asterosap-induced Ca2+ elevation using different Ca2+ channel antagonists. Fluo-4 AM, a cell permeable Ca2+ sensitive dye was used to determine the channel caused by the asterosap-induced Ca2+ elevation in spermatozoa. Different L-type Ca2+ channel antagonists, a non specific Ca2+ channel antagonist (nickel chloride), and a store-operated Ca2+ channel (SOC) antagonist do not show any significant response on asterosap-induced Ca2+ elevation, whereas KB-R7943, a selective inhibitor against Na+/Ca2+ exchanger (NCX) inhibited effectively. We also analyzed the flagellar movement of spermatozoa in artificial seawater (ASW) containing the asterosap at 100 nM ml?1. We found that spermatozoa swam vigorously with more symmetrical flagellar movement in asterosap than in ASW and KB-R7943 significantly inhibited the flagellar movement.DOI: http://dx.doi.org/10.3329/pa.v19i1.17358 Progress. Agric. 19(1): 79 - 88, 2008 

A synthetic decapeptide from a conserved ZP3 protein domain induces the G protein-regulated acrosome reaction in bovine spermatozoa

2005 ◽  
Vol 63 (6) ◽  
pp. 1682-1694 ◽  
Author(s):  
E. Hinsch ◽  
V.A. Aires ◽  
F. Hedrich ◽  
S. Oehninger ◽  
K.-D. Hinsch
Keyword(s):  
G Protein ◽  
Acrosome Reaction ◽  
Protein Domain ◽  
Bovine Spermatozoa

EFFECTS OF YEARLING WEIGHT SELECTION IN SHORTHORN BEEF CATTLE ON AGE-OF-DAM ADJUSTMENT FACTORS

1990 ◽  
Vol 70 (3) ◽  
pp. 963-965
Author(s):  
J. C. OLTHOFF ◽  
G. H. CROW ◽  
G. W. RAHNEFELD
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Key Words ◽  
Selection Line ◽  
Weaning Weight ◽  
Performance Change ◽  
Adjustment Factors ◽  
Over Time

Lines within a breed which differ in their level of performance may require different age-of-dam adjustment factors in the same way that different breeds do. Age-of-dam adjustments calculated from a control and a yearling weight selection line indicated lower values in the selected line for calf birth weight, weaning weight and yearling weight for 2- and 4-yr-old dams. Trends for adjustment factors in each line over time were generally not significant but tended to diverge. Age-of-dam adjustment factors within a breed may need to be reevaluated at intervals as levels of performance change. Key words: Beef cattle, age of dam adjustment, selection, yearling weight

A retrospective look at 80 years of silvicultural research at Petawawa

1999 ◽  
Vol 75 (3) ◽  
pp. 385-388
Author(s):  
Steve D'Eon
Keyword(s):  
Experimental Design ◽  
Key Words ◽  
Research Priorities ◽  
Factorial Designs ◽  
Forest Research ◽  
Permanent Sample Plots ◽  
Site Characteristics ◽  
Over Time ◽  
Long Term Studies

Canada's oldest forest research plot was laid out at Petawawa in 1918. Since then, hundreds of researchers have established plots, gathered data, and published results utilizing the Petawawa Research Forest. Many of the projects and plots were designed as long-term studies meant to endure and be re-measured over the decades. Although control plots were utilized, these early experiments were established prior to the benefits of repetition and experimental design. Later experiments were installed with three or more reps and factorial designs strengthening their analytical capabilities. Research priorities have shifted over time from documenting the results of a particular silvicultural treatment to understanding why silvicultural responses are obtained. Factors that influenced the continuance of some studies and the discarding of others are reviewed.Some studies achieved their original goals and have been continued for longer periods or utilized for additional goals. Characteristics such as tenure, experimental design, and site characteristics are described for several of these studies. Key words: long-term research, permanent sample plots, Petawawa

Relocation of myosin and actin, kinesin and tubulin in the acrosome reaction of bovine spermatozoa

2009 ◽  
Vol 21 (2) ◽  
pp. 364 ◽  
Author(s):  
Ifigenia Oikonomopoulou ◽  
Hitesh Patel ◽  
Paul F. Watson ◽  
Peter D. Chantler
Keyword(s):  
Molecular Motors ◽  
Acrosome Reaction ◽  
Molecular Motor ◽  
Calcium Ionophore ◽  
Cell Types ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Sequence Of Events ◽  
Bovine Spermatozoa ◽  
Number Of Cells

The mammalian acrosome reaction is a specialised exocytotic event. Although molecular motors are known to be involved in exocytosis in many cell types, their potential involvement in the acrosome reaction has remained unknown. Here, it has been shown that actin is localised within the equatorial segment and in the marginal acrosomal ridge of the heads of unreacted bull spermatozoa. Myosins IIA and IIB are found within the anterior acrosomal margins of virtually all sperm cells and, less prominently, within the equatorial segment. Tubulin was detected in the equatorial segment and around the periphery of the acrosome while kinesin was prominent in the equatorial segment. After induction of the acrosome reaction by means of the calcium ionophore A23187, the number of cells exhibiting actin fluorescence intensity in the anterior acrosomal margin decreased four-fold and those displaying equatorial segment fluorescence decreased 3.5-fold; myosin IIA immunofluorescence decreased in intensity with most spermatozoa losing equatorial staining, whereas there was little change in the distribution or intensity of myosin IIB immunofluorescence, except for a ~20% decrease in the number of cells exhibiting acrosomal staining. Tubulin became largely undetectable within the head and kinesin staining spread rostrally over the main acrosome region. A possible sequence of events that ties in these observations of molecular motor involvement with the known participation of SNARE proteins is provided.

scholarly journals Sprint training restores normal contractility in postinfarction rat myocytes

2000 ◽  
Vol 89 (3) ◽  
pp. 1099-1105 ◽  
Author(s):  
Lian-Qin Zhang ◽  
Xue-Qian Zhang ◽  
Timothy I. Musch ◽  
Russell L. Moore ◽  
Joseph Y. Cheung
Keyword(s):  
Contractile Function ◽  
Sprint Training ◽  
Maximal Contraction ◽  
Contraction Amplitude ◽  
Rat Hearts ◽  
Intracellular Ca ◽  
Rat Myocytes ◽  
Time Required ◽  
Cellular Ca ◽  
Homeostatic Mechanisms

The significance of 6–8 wk of high-intensity sprint training (HIST) on contractile abnormalities of myocytes isolated from rat hearts with prior myocardial infarction (MI) was investigated. Compared with the sedentary (Sed) condition, HIST attenuated myocyte hypertrophy observed post-MI primarily by reducing cell lengths but not cell widths. At high extracellular Ca2+ concentration (5 mM) and low pacing frequency (0.1 Hz), conditions that preferentially favored Ca2+ influx over efflux, MI-Sed myocytes shortened less than Sham-Sed myocytes did. HIST significantly improved contraction amplitudes in MI myocytes. Under conditions that favored Ca2+ efflux, i.e., low extracellular Ca2+ concentration (0.6 mM) and high pacing frequency (2 Hz), MI-Sed myocytes contracted more than Sham-Sed myocytes. HIST did not appreciably affect contraction amplitudes of MI myocytes under these conditions. Compared with MI-Sed myocytes, HIST myocytes showed significant improvement in time required to reach one-half maximal contraction amplitude shortening, maximal myocyte shortening and relengthening velocities, and half time of relaxation. Our results indicate that HIST instituted shortly after MI improved cellular contraction in surviving myocytes. Because our previous studies demonstrated that, in post-MI myocytes, HIST improved intracellular Ca2+ dynamics, enhanced sarcoplasmic reticulum Ca2+ uptake and Ca2+ content, and restored Na+/Ca2+ exchange current toward normal, we hypothesized that improvement in MI myocyte contractile function by HIST was likely mediated by normalization of cellular Ca2+ homeostatic mechanisms.

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