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U. LAVON

Summary.

Boar, bull, ram and rabbit seminal plasma proteins were studied by gel disc electrophoresis at pH 4·5 and 8·6 and by isoelectric focusing on plates using ampholines of pH range 3 to 10.

The number of proteins identified in the seminal plasma of the four species using gel disc electrophoresis was greater than had been found in most previous reports, more being identified in ram and rabbit than in boar and bull seminal plasma. Bovine plasma albumin and γ-globulin each appeared as a number of protein bands.

Due to the better resolution, the number of proteins found in the same seminal plasma samples using isoelectric focusing was greater than that obtained with gel disc electrophoresis.

Boar seminal plasma proteins were found to be basic in character. Those of the other animals possessed acidic, neutral and basic isoelectric points. This was more effectively demonstrated by the isoelectric focusing technique. The bovine plasma albumin and γ-globulin appeared on the plates as groups of eight and twelve to fourteen components, respectively. Their similarity to the seminal plasma proteins was very small.

The protein pattern obtained on the ampholine plate was affected by the site of sample application along the pH gradient. This was more clearly shown when the pH gradient was established before a sample was placed on the plate. Possible explanations for these alterations are discussed.

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D. Amir and U. Lavon

Summary.

Protein changes in epididymal and ejaculated spermatozoa were studied in bulls treated orally on alternate days with a total of 10 doses (each of 4 mg/kg body weight) of ethylene dibromide. No significant changes were found in the total nitrogen, amino acid or lipoprotein contents of the spermatozoa collected either from the epididymis 1 day after the last dose, or from ejaculates 9-13 days after the end of the treatment. Significant changes were found in the percentage composition of amino acids of the sperm proteins and lipoproteins but the changes differed in the caput, cauda and ejaculated spermatozoa.

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U. LAVON and J. C. BOURSNELL

Summary.

Boar seminal plasma, vesicular secretion and epididymal plasma proteins were studied by gel disc electrophoresis at pH 4·5 and 8·6 and by isoelectric focusing in tubes and on plates using ampholines of pH range 3 to 10.

The number of protein bands obtained in the gel disc electrophoresis was fifteen to twenty for all the samples. A similarity between the proteins of the seminal plasma and the vesicular secretion was greater at pH 4·5 than at pH 8·6. The epididymal plasma showed a different separation picture.

The better resolution of the isoelectric focusing revealed a greater number of proteins. Similar protein patterns were found for the vesicular secretion and the seminal plasma in the basic part of the pH range, where the majority of the proteins of these fluids are found. The proteins of the epididymal plasma, on the other hand, possess more neutral isoelectric points and their contribution to the seminal plasma is smaller than that of the vesicular secretion. Only a few of the epididymal plasma proteins and of the minor vesicular secretion proteins could be found in the neutral and acidic regions of the seminal plasma. This is largely the result of the dilution of these accessory secretions occurring during ejaculation.

Differences in the protein pattern of the seminal plasma of various animals could be found. The importance of these differences is as yet unknown.

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U. LAVON and J. C. BOURSNELL

Summary.

The epididymal and seminal vesicular contributions to splitejaculate fractions from boars were analysed for sperm concentration, glycerylphosphorylcholine (GPC), total-N, ethanol-soluble and insoluble N, citrate, zinc and haemagglutinin. The same components were also determined in epididymal plasma (EP), vesicular secretion (VS) and whole seminal plasma (SP). Isoelectric focusing of protein patterns was studied in the fractions.

With the exception of haemagglutinin, the components were present to a major extent in either VS or EP and in lower concentrations in the other secretion. The parameters in VS or EP were positively correlated among themselves and negatively correlated with most of the parameters of the other fluid. The correlation coefficients were not significant in all cases for individual animals, but the degree of significance was greater for the over-all correlations.

The EP components were mainly secreted in the first three or four fractions, but occasionally from fraction four onwards. Those of VS were emitted during the entire ejaculation, the maximum occurring in the sperm-rich fraction or the immediately succeeding fraction. The first fractions were devoid of VS components in only one case.

The majority of the EP proteins could be identified electrophoretically in the sperm-rich fractions, but the protein patterns in the other fractions were similar to those of VS. The results are discussed and compared with previous findings.

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U. LAVON, R. VOLCANI and D. DANON

Summary.

Changes occurring in the proteins of bovine spermatozoa during their migration from the caput to the cauda epididymidis were studied.

The percentage of total nitrogen in the dry matter was greater in the cauda than in the caput spermatozoa, but the nitrogen content/109 cells was less in the cauda spermatozoa. The amount of DNA for the same number of cells remained constant during this stage of maturation. The decrease in the nitrogen content indicated a loss of protein during maturation of bovine spermatozoa in the epididymis. Amino acid analysis of the dry matter of the sperm cells showed an increase in the percentage of arginine and cystine and a decrease in the percentage of glutamic and aspartic acids, alanine, methionine, isoleucine and leucine during passage of spermatozoa through the epididymis. Lipoprotein content decreased during the maturation of the sperm cells, and a slight increase occurred in several of the other proteins. Amino acid analysis of the extracted proteins showed differences in the percentage of several amino acids between caput and cauda spermatozoa in the F1 and F2 fractions. Gel disc electrophoresis of the various caput and cauda sperm proteins indicated a different number of bands and a different colour intensity for those fractions in which a different amino acid composition was found.

The results suggest that the lipoproteins of the cell membrane may be the site of alterations in the quantity, composition and electrophoretic behaviour of the proteins of bovine spermatozoa during their maturation.

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U. LAVON, R. VOLCANI and D. DANON

Previous estimates of dry matter content in spermatozoa have been variable (Ray Sarkar, Luecke & Duncan, 1947; VanDemark, 1948; Barer, Ross & Tkaczyk, 1953) but some of the methods employed might have altered the chemical composition of the spermatozoa. Therefore, a method was needed that would facilitate the separation of spermatozoa from seminal plasma and, at the same time, would ensure minimal exchange of water and other substances to and from the cells.

Ballentine & Burford (1960) have separated, simply and effectively, various cells from their suspending medium by differential flotation (df). Our previous studies on the specific gravity (sp.gr.) and density distribution of bull spermatozoa were based on df. The spermatozoa thus separated from the seminal plasma are not altered in their composition

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U. LAVON, R. VOLCANI and D. DANON

Summary.

Several changes occurring during sperm maturation in the epididymis were determined either for spermatozoa obtained from consecutive ejaculates or from the caput and the cauda epididymidis.

A significant decline was found in the fresh weight of the cells during maturation and was attributed to dehydration and to a loss of certain components from the cells. This was proved by the increase in the % dry matter and by the decrease in the content of the dry matter, the total lipids and of the main lipid fractions of the cells during maturation.

The increase in the % dry matter and the decrease in the % total lipids in the dry matter explain the increase in the specific gravity of spermatozoa during maturation.

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U. LAVON, J. C. BOURSNELL and P. A. BRIGGS

In an earlier study on the characteristics of boar seminal plasma (Boursnell, Nelson & Cole, 1966), use was made of ultrafiltrates, though this did not include an investigation of the ultrafiltered proteins. Recently, preliminary determinations have shown that the ultrafiltrate contains 4% of the seminal plasma protein and is devoid of the haemagglutinating protein H (Boursnell & Briggs, 1969).

In a further study of the nature of this protein material, isoelectric focusing on polyacrylamide plates was used. Comparisons of this material were made with whole seminal plasma, seminal plasma from which the haemagglutinin was absorbed with washed bull spermatozoa (Boursnell, 1967) and with proteins `A Seph' and `A Dial' prepared from boar seminal plasma as described by Boursnell et al. (1966). `A Seph' should contain the haemagglutinin and `A Dial' should lack it (Boursnell

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U. LAVON, R. VOLCANI, D. AMIR and D. DANON

There are a few reports on the changes in specific gravity (s.g.) during maturation and ageing of spermatozoa. Lindahl & Kihlström (1952) found the s.g. of bull spermatozoa to range between 1·240 and 1·334. The s.g. decreased from 1·2867 to 1·2668 when three consecutive ejaculates were collected. Lindahl & Thunqvist (1965) found a value of 1·10 to 1·12 for the s.g. of bull epididymal spermatozoa and a value of 1·21 to 1·33 for ejaculated spermatozoa. Assuming that spermatozoa from the epididymis and from later ejaculates are younger than those from the first ejaculates, they suggested that the s.g. of spermatozoa increases with maturation and ageing.

Spermatozoa were taken from different parts of the bull testis in order to ascertain whether their s.g.

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U. LAVON, R. VOLCANI, D. AMIR and D. DANON

There are few reports in the literature concerning the specific gravity (s.g.) of mammalian spermatozoa and seminal plasma. Lindahl & Kihlstrom (1952) using umbradil salts of methylglucamine as the suspending medium found bull spermatozoa to have a specific gravity of 1·241 to 1·335. Lindahl & Thunqvist (1965) using Ficoll (polysaccharide of sucrose) obtained values of 1·21 to 1·33. These results are considerably higher than the specific gravity of 1·0975 reported by Yamane (1920) for the stallion, and 1·132 reported by Beatty (1964) for the rabbit. They also seem very high in view of the chemical composition of the dry matter and water content as given by Mann (1964) and VanDemark (1948).

The specific gravity of bull seminal plasma reported by Anderson (1946) was 1