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Biomedical subjects

B Bartoov

Publications and source records attributed to B Bartoov.

At least 55 records · Page 3Linked to original sources
PubMed1983

Sperm cell motility as a new experimental model for toxicological studies.

The effects of environmental and toxicological factors were tested in a new and "simple" biological system; the collective motility exhibited by ram spermatozoa. Motility of highly concentrated semen (greater than 1 X 10(9) cells/ml) was evaluated objectively with a multichannel reflectospermiograph (RSG) connected to a minicomputer for an on-line analysis. The effect was tested on one of the energy-producing systems in the sperm cells, while the other was inhibited by 2-deoxy-D-glucose or antimycin-A so that the energy source for motility was known. The effects of the addition of ethanol to the semen in various concentrations, as well as various levels of oxygen in the environment were tested. When motility of the sperm cells was driven by mitochondrial respiration, the intensity and duration of motility was inhibited significantly above a threshold level. At the same level of ethanol, the motility was not significantly affected when the energy source was the fructolysis pathway. The effects of oxygen level were tested below and above the normal oxygen level (21% O2). When fructolysis was inhibited, the motility was fully dependent on oxygen supply, namely, that lower levels of oxygen inhibited motility. It was also found that under higher levels of O2 (hyperbaric hyperoxia conditions) the motility was inhibited due to the known oxygen toxicity effects.

Animals↗
PubMed1982

Transmission electron microscope morphogram of progressive motile sperm cell fraction separated from teratozoospermic human semen.

Teratozoospermic semen specimens were separated, with the aid of a specially designed separation chamber, into an upper progressive motile sperm fraction and a lower fraction containing a high percentage of sperm cells of poor or no motility, and immature germinal cells. Analysis of the TEM morphograms of progressive motile cell fractions and original teratozoospermic semen revealed that 15 various malformations were improved significantly in the motile cell population due to the cell separation technique.

Cell Separation↗
PubMed1981

Sperm Motility Analyzer (SMA), a practical tool of motility and cell concentration determinations in artificial insemination centers.

A description of a new instrument, which analyzed objectively sperm cell concentration and collective motility of a fresh semen sample of bull or ram, is reported. A display read-out of sperm cell concentration for an aliquot of the undiluted semen sample in the range from 200 x 10(6) to 4000 x 10(6) cell/ml with an accuracy of +/- 5% is shown immediately by optical density units. A significant correlation coefficient (0.918, p < 0.01) was obtained between these units and cell concentrations, as determined in four A.I. centers in the U.S. and Canada. The intensity of the sperm collective motility is expressed as an objective index (SMI) which was significantly correlated to the fraction of the live motile cells in the semen sample. The SMI values were corrected for a possible error originating from the difference in sperm cell concentration by an empirical equation. Due to the accuracy, repeatability and objectivity of evaluating the semen quality and also the simplicity of operation, as well as the possibility of utilizing the measured semen sample for further processing, the Sperm Motility Analyzer (SMA) seems suitable as a standard tool for semen quality control in the A.I. centers.

Journal Article↗
PubMed1981

Effects of hyperbaric oxygenation on spermatozoan motility driven by mitochondrial respiration.

The effects of hyperbaric oxygen (HPO) on ram sperm motility driven by mitochondrial respiration are described. Sperm motility was assessed by a multichannel optical objective technique (Reflectospermiography). Motility was simultaneously measured from four semen sample at various pH levels in room air atmosphere and compared with four other samples exposed to various high oxygen (100%) levels 1, 3, 5, and 7 atmospheres absolute (ATA). Two main effects were observed under HPO oxygen: 1) shortening of motility durations, and 2) abolishment of motility regulation by pH. These effects were found to be attributed to the hyperoxic conditions. Above 3 ATA the effects of HPO with regard to the above-described parameters were considered toxic. Below this pressure level the effect of HPO was found to be moderate. The exposure of sperm cells to HPO (7 ATA) did not cause morphological alterations. Also, exposure of seminal plasma to HPO (7 ATA) for 150 min did not cause any toxic effects when added to washed spermatozoa. The ram semen preparation seems to provide a useful model for studying the mechanisms underlying HPO effects.

Animals↗
PubMed1981

Incorporation of [3H]thymidine into mtDNA of ram spermatozoa.

Freshly ejaculated spermatozoa from 6 rams incorporated [3H]-thymidine only after a lag period of 4 h. The thymidine incorporation was dependent on the time after ejaculation regardless of the rate of fructolysis, which was controlled by cold shock. The DNA synthesis period lasted for 3 h followed by a degradation period of 2 h. This synchronized level of labelling of DNA with tritiated thymidine was not due to bacterial contamination, sperm cell mitosis, mitochondrial division, or DNA repair. The fact that the maximal level of the DNA synthesis was dependent upon the external pH of the seminal plasma, in a parabolic fashion with a minimum around pH 6.3, indicated that this activity was of a 'metabolic' type. The sensitivity of the sperm DNA synthesis to 10 micrograms ethidium bromide/ml indicated that it was of a mitochondrial origin.

Animals↗
PubMed1981

A fluorometric-reflectometric technique for simultaneous measurement of pH and motility in ram semen.

An optical technique for simultaneous assessment of pH and motility in ram semen was described. Motility was evaluated by the measurement of changes in intensity of reflected light from semen samples illuminated with 366 nm light. pH was measured by using a pH-sensitive fluorescent indicator (umbelliferone). From the changes in fluorescence intensity (450 nm) as a function of the pH of the semen, a calibration curve was constructed. The relationship between pH changes and motility in various metabolic conditions were described. Different kinetics for pH changes occurred when sperm motility was driven by both mitochondrial respiration and fructolysis or by either one of them. An analysis of the fluorescence signal from extracellular or cellular fractions of semen suggested that the pH measurement reflected extracellular pH.

Animals↗
PubMed1980

A new optical technique for evaluating collective motility of ram and bull ejaculated spermatozoa.

A new, non-destructive, objective technique for measuring collective motility of highly-concentrated ram and bull semen is described. The principle is based on changes in the reflected light scattered by motile spermatozoa. These changes can be recorded as a continuous analog wave pattern (Reflectospermiogram-RSG) and are correlated to the intensity of the turbulent motility as evaluated subjectively with an ordinary light microscope. Ram spermatozoa have, after ejaculation, a typical motility pattern, i.e., high, stable activity for about 20 min, then a period during which the motility decreases at a constant rate, and finally, a period with a low but rather constant activity. The usefulness of the technique has been demonstrated in various types of experiments.

Animals↗
PubMed1980

A multi-channel system for the measurement of spermatozoan collective motility.

A new multi-channel optical system for objective evaluation of sperm motility is described. The principle of the technique is based on the measurement of changes in the intensity of light scattered from semen samples thermoregulated at 38 degrees C. These changes were recorded continuously as analog waves (Reflectospermiogram--RSG). Changes in the intensity of sperm motility as a function of time from ejaculation were simultaneously measured in 8 equal semen samples from single ejaculate. By analyzing the variations in results, the sensitivity of the technique was defined. In order to demonstrate the use of the technique, the effect of various concentrations of ethanol on sperm motility has been described. The exposure of sperm cells to 366 nm light used in the system did not alter their ultrastructure, as was observed by electron microscopy. This objective, relatively easy to perform and highly informative technique can be of great value in research studies.

Animals↗
PubMed1980

Uniqueness of sperm mtDNA as compared to somatic mtDNA in ram.

Sperm mtDNA exhibits unique physicochemical properties compared with mtDNA from somatic tissues in the ram. The buoyant density of sperm mtDNA was 1,6983 g/cm3 while the brain, heart and liver mtDNAs was about 1.7005 g/cm3. The Tm of the liver and sperm mtDNA was 71.0 degrees C and 69.5 degrees C, respectively. The G + C content of sperm mtDNA was 3.0 moles % lower than the liver mtDNA. The contour length of the circular sperm mtDNA was 5.01 micrometers compared with the liver mtDNA with contour length of 5.33 micrometers.

Animals↗
PubMed1980

The effect of pH on ram sperm collective motility driven by mitochondrial respiration.

Ram sperm cells treated with 0.02 M 2-deoxy-D-glucose exhibit collective motility which is driven only by mitochondrial respiration. This motility was measured, by means of multichannel optical objective technique, under various [H+] concentrations (pH range 5.6-7.2) buffered by 0.125 M phosphate buffers. Semen was divided into 8 aliquots and motility was monitored simultaneously for intensity and duration within 10 min of ejaculation until its complete cessation. The optimal pH range found for the two above-mentioned parameters was in the range of 6.0-6.5. A certain characteristic of the pattern of sperm motility intensity (an oscillations phenomenon) was similarly related to pH. It is suggested that the mechanisms underlying the relationship between pH and motility are rather metabolic. Concerning the results, some practical implications are introduced.

Animals↗
PubMed1980

DNase II in bull and ram sperm tail and mitochondria.

Extracts of bull and ram sperm tails were prepared by DTT and CTAB treatment. Such extracts contained deoxyribonuclease II, degrading only native double-stranded DNA at acid pH (3.9--4.5). At least three distinguishable DNase II activities were found in these extracts as judged by their sensitivity to thiol compounds and various anions and cations. The deoxyribonuclease II activity is apparently located in or in association with the mitochondria.

Animals↗
PubMed1980

Replicative intermediates of ram sperm mitochondrial DNA.

Replication of mtDNA from ejaculated ram spermatozoa was demonstrated by electron microscopy. Twelve percent of mtDNA circular molecules isolated either from ram sperm cells or from rat liver mitochondria were double-forked. These replicative intermediates appeared in four distinct steps of replication: 3.9%, 21.0%, 27.8%, and 44% of the circular contour length. The biological significance of sperm mitochondrial DNA replication is discussed.

Animals↗
PubMed1980

Morphological characterization of abnormal human spermatozoa using transmission electron microscopy.

A morphological analysis of ejaculated human abnormal spermatozoa is presented. Eighteen different malformations are characterized, based on (a) the cell's organelle where they appeared, (b) the possible developmental stage when they occurred, and (c) the possible mechanism responsible for a specific appearance. The forces that govern the shaping of the spermatozoan head are described in detail. The possible mechanism responsible for chromatin subcondensation, acrosome malformation, kinked tail forms, and mitochondrial malformations are discussed.

Acrosome↗
PubMed1977

Ram sperm mitochondrial DNA.

Circular DNA was isolated from mitochondrial fractions of ram spermatozoa by SDS treatment followed by convex sucrose gradient centrifugation. The DNA had a contour length of 5.0 micron. Its buoyant density was 1.6983 g cm-3, which was smaller than two nuclear DNA components with buoyant densities of 1.6999 and 1.7156 g cm-3, found in ram spermatozoa. The Tm of the mitochondrial DNA was 69.7 degrees C. The mole fraction G+C calculated from the buoyant density and melting temperature was 39.1% and 38.6%, respectively.

Animals↗
PubMed1975

Rat testis mitochondrial adenylate cyclase. Partial purification and characterization.

1. Adenylate cyclase (EC 4.6.1.1) from rat testis mitochondria has been solubilized by treatment with the non-ionic detergent Lubrol PX. The soluble enzyme was further purified by DEAE-cellulose chromatography. 2. The specific activity of the adenylate cyclase eluted from the DEAE-cellulose column was found to be four times higher than that of an intact mitochondrial preparation. At this step the enzyme shows a sedimentation coefficient of 4.2 S and a diffusion coefficient (D) of 3.12 - 10- minus 7 cm-2/sec. 3. Solubilization of the adenylate cyclase resulted in loss of responsiveness to gonadotrophic hormones. Addition of phosphatidylserine to the soluble preparation partially restored the activation of adenylate cyclase by human chorionic gonadotrophin. 4. The results of this study suggest that the activity of the adenylate cyclase may be dependent on the membrane-bound phospholipids and that the enzyme attached to the mitochondrial membranes has some properties which are similar to the adenylate cyclase found to be associated with other membrane systems of the cell.?

Adenosine Triphosphatases↗