Glycolytic enzymes of fowl and turkey spermatozoa

• 1.1. It was confirmed that, under anaerobic conditions, fowl spermatozoa formed lactate from glucose thirteen times faster than turkey spermatozoa.
• 2.2. The profiles of glycolytic enzyme activities were similar for spermatozoa from both species; however fowl spermatozoal activities were generally 2- to 4-fold higher.
• 3.3. Exceptions were glycerophosphate mutase and lactate dehydrogenase activities which were respectively 9.5 and 41 times greater in fowl spermatozoa.
• 4.4. In both species, spermatozoal glyceraldehyde-3-phosphate dehydrogenase had the lowest activity of the glycolytic enzymes.

     

Phospholipids and phospholipid-bound fatty acids and aldehydes of spermatozoa and seminal plasma of rhesus monkeys.

The major components of the phospholipids of rhesus monkey spermatozoa are phosphatidyl choline (33%), phosphatidyl ethanolamine (25%), ethanolamine plasmalogen (16-1%), sphingomyelin (8-1%), choline plasmalogen (6-9%) and cardiolipin (4-5%). The major phospholipid-bound fatty acids are 16:0, 18:0, 18:1 and 22:6; the major fatty aldehydes are 15:0, 16:0 and 18:2. The same phospholipids are also present in the seminal plasma.     

Fertilizing capacity and ultrastructure of fowl and turkey spermatozoa before and after freezing.

The fertilizing capacity, motility and ultrastructure of fowl and turkey spermatozoa were examined at various stages of the freezing process. For both species, fertility and motility were depressed after equilibration with dimethyl-sulphoxide at 5 degrees C. After freezing, motility was maintained at 55% for fowl spermatozoa and 40% for turkey spermatozoa; however, fertility was 55% for the fowl and 0% for the turkey. Qualitatively, the damage to the spermatozoa of both species was nearly identical, as revealed by scanning and transmission electron microscopy. The plasmalemma was the primary site of damage. 'Bent' spermatozoa, coiled tails and swollen mitochondria were also present. Damage to the acrosome was only observed in spermatozoa which had been frozen to -180 degrees or -196 degrees C. These changes were attributed to adverse osmotic conditions. Binding of cationic ferritin to the plasmalemma of spermatozoa from both species remained unaltered.     

The hydrogenation of phospholipid-bound unsaturated fatty acids by a homogeneous, water-soluble, palladium catalyst

The hydrogenation of unsaturated phospholipids by palladium di(sodium alizarine monosulphonate) activated for 5 min under H2 proceeded rapidly at 20 degrees C and 1 atm. H2. Multibilayer liposomes of dioleoyl- and dilinolenoylphosphatidylcholine were hydrogenated at similar rates while dilinoleoyl- and 1-palmitoyl-2-oleoylphosphatidylcholine were hydrogenated at slightly slower rates. The reduction of polyunsaturated fatty acids gave rise to a variety of natural and unnatural positional cis and trans isomers which were largely reduced further to saturated fatty acids as the hydrogenation continued. Dioleoylphosphatidylethanolamine was attacked by the catalyst more slowly at 20 degrees C than was the equivalent phosphatidylcholine molecular species. Experiments conducted using mixtures of phosphatidylethanolamine and phosphatidylcholine in varying proportions also suggested that phospholipids are slightly more susceptible to catalytic hydrogenation in the bilayer phase than in the hexagonalII phase. Understanding the sequence of hydrogenation reactions involving these one and two component lipid preparations is useful in interpreting the action of the palladium catalyst on living cells under the same mild conditions.     

Metabolism of fatty acids by bovine spermatozoa

The incorporation of (14)C-labelled myristic, palmitic, stearic, oleic and linoleic acids in vitro into the lipids of bovine spermatozoa was measured at intervals from 2min to 2h. All acids were rapidly incorporated into diglycerides, myristic acid being metabolized to the greatest extent. Whereas the low incorporation of acids into total phospholipids reflected the relative stability of the major phospholipid fractions in sperm, the minor phospholipids, particularly phosphatidylinositol, showed comparatively high metabolic activity. Although, in general, saturated acids were incorporated more actively than unsaturated substrates, stearic acid was poorly incorporated into all lipids except phosphatidylinositol. In regard to fatty acid composition of sperm lipids it was notable that diglycerides contained myristic acid as the major component, and this acid was also a prominent moiety of phosphatidylinositol. Docosahexaenoic acid was the principal fatty acid of the major phospholipid classes. These findings have been discussed in relation to the role of lipids in the metabolism of spermatozoa.     

Differential incorporation of fatty acids into and peroxidative loss of fatty acids from phospholipids of human spermatozoa

Intact human sperm incorporated radiolabelled fatty acids into membrane phospholipids when incubated in medium containing bovine serum albumin as a fatty acid carrier. The polyunsturated fatty acids were preferentially incorporated into the plasmalogen fraction of phospholipid. Uptake was linear with time over 2 hr; at this time sufficient label was available to determine the loss of fatty acids under conditions of spontaneous lipid peroxidation. Loss of the various phospholipid types, the loss of the various fatty acids from these phospholipids, and the overall loss of fatty acids were all first order. The loss of saturated fatty acids was slow with first order rate constant k₁ = 0.003 hr^?1; for the polyunsaturated fatty acids, arachidonic and docosahexaenoic acids, k₁ = 0.145 and 0.162 hr^?1, respectively. The rate of loss of fatty acids from the various phospholipid types was dependent on the type, with loss from phosphatidylethanolamine being the most rapid. Among the phospholipid types, phosphatidylethanolamine was lost at the greatest rate. Analysis of fatty acid loss through oxidation products was determined for radiolabelled arachidonic acid. Under conditions of spontaneous lipid peroxidation at 37°C under air in the absence of albumin, free arachidonic acid was found in the medium, along with minor amounts of hydroxylated derivative. All the hydroperoxy fatty acid remained in the cells. In the presence of albumin, all the hydroperoxy fatty acid was found in the supernatant bound to albumin; none could be detected in the cells. Albumin is known as a very potent inhibitor of lipid peroxidation in sperm; its action may be explained, based on these results, as binding the damaging hydroperoxy fatty acids. These results also indicate that a phospholipase A₂ may act in peroxidative defense by excising a hydroperoxy acyl group from phospholipid and providing the hydroperoxy fatty acid product as substrate to glutathione peroxidase. This formulation targets hydroperoxy fatty acid as a key intermediate in peroxidative degradation. © 1995 wiley-Liss, Inc.     

Lactate dehydrogenase isozymes in the spermatozoa of the domestic fowl, Gallus domesticus and turkey, Meleagris gallopavo.

1. Electrophoresis of extracts of turkey spermatozoa for lactate dehydrogenase activity revealed the usual five tissue LDHs (LDH-1 to LDH-5). 2. The presence of LDH-X (the spermatozoan-specific isozyme) was not obvious. 3. Only one band was present on electrophoresis of fowl spermatozoan extracts and it coincided with LDH-1 (heart type). 4. Kinetic investigations, the use of inhibitors and the heat-stability test confirmed that the fowl spermatozoan LDH was probably LDH-1 and not LDH-X.     

The development of thermoregulation in turkey and guinea fowl hatchlings: similarities and differences

The development of thermoregulation was studied in turkeys (Meleagris gallopavo, 60.5 g) and guinea fowl (Numida meleagris, 33.5 g) from 2 to 24 h after hatching. Thermoregulation was measured at different ages during 1 h of cold exposure (20°C). Final body temperature rose linearly with age in turkeys, but reached a plateau in guinea fowl between 12 and 16 h. At 2 h after hatch final body temperature was highest in guinea fowl, while at 24 h after hatch there was no difference between the species. The development of mass-specific metabolic rate with age resembled the pattern of final body temperature. At 2 h post-hatch mass-specific metabolic rate was highest in guinea fowl; however, at 24 h post-hatch there was no difference between the species. since mass-specific metabolic rate reached a plateau in guinea fowl at 16 h. In turkeys mass-specific dry thermal conductance decreased with age initially, while in guinea fowl it remained stable. Nevertheless, at both 2 and 24 h after hatch mass-specific wet conductance did not differ significantly between the species. In turkeys mass-specific wet conductance increased initially. This increase in mass-specific wet conductance may be due to the rapid onset of feather growth in turkeys. The O₂ consumption per breath doubled during the first 24 h in turkeys but remained stable in guine fowl. This suggests that at least two different developmental patterns of O₂ intake exist within Galliformes. The results show that 2 h post-hatch the thermoregulatory ability was lowest in turkeys, despite their larger body mass. However, at 24 h post-hatch the difference between the species was not significant, because the thermoregulatory ability had increased more in turkeys.Abbreviations B _f breathing frequency - BM body mass - BMR basal metabolic rate - C _D mass-specific dry thermal conductance - C _w mass-specific wet thermal conductance - HI homeothermy index - H _E evaporative heat loss - H _B loss of stored body heat - MR metabolic rate - M _MS mass-specific metabolic rate - RH relative humidity - I _A ambient temperature - T _Bi initial body temperature - T _Bf final body temperature - VO₂ volume oxygen consumed - VCO₂ volume carbon dioxide produced     

The mechanisms of reversible immobilization of fowl spermatozoa at body temperature

Intact fowl spermatozoa became almost immotile at 40 degrees C, but motility increased significantly at 30 degrees C. The oxygen consumption at both temperatures was 8-11 microliters O2/10(10) spermatozoa.min-1. The ATP concentration at 40 degrees C was higher than that at 30 degrees C but ADP concentration at 30 degrees C was higher than that at 40 degrees C. Consequently, the ATP/ADP ratio at 30 degrees C (1.9-2.2) increased to 3.5-3.7 at 40 degrees C. The motility of intact spermatozoa at 40 degrees C was effectively restored by 2 mM-Ca2+, 10% seminal plasma and 10% peritoneal fluid taken at the time of ovulation. In contrast, these effectors did not restore the motility of demembranated spermatozoa at 40 degrees C. Motility of demembranated spermatozoa was restored at 30 degrees C. These results suggest that the immobilization of fowl spermatozoa at 40 degrees C occurs due to a decrease in flagellar dynein ATPase activity. Furthermore, the action of effectors for motility such as Ca2+ may not be directly on the axoneme, but mediated by solubilized substances which have been removed by demembranation of the spermatozoa.     

The effect of various PGI2 analogues on free and phospholipid-bound fatty acids in rat brain, following complete ischaemia, normobaric and hypobaric hypoxia.

The effect of various prostacyclin analogues on free and phospholipid-bound fatty acids in rat brain following complete ischaemia, normobaric and hypobaric hypoxia were investigated. Both ischaemic and hypoxic conditions cause a significant rise in both unsaturated (arachidonic and docosahexaenoic) and saturated (palmitic and stearic) fatty acids. Under same conditions, a significant fall in phosphatidylinositol level in brain was observed. Prostacyclin and its analogues significantly reduce the rise of free fatty acids, as well as the decrease of phosphatidylinositol.     

Effect of calcium and fatty acids on the isolation of stallion spermatozoa in BSA

Fifty ejaculates, ten from each of 5 mature stallions, were utilized to study the effects of calcium and fatty acids on equine spermatozoa which were isolated in 3% Bovine Serum Albumin (BSA). The ejaculates were evaluated for percent motile spermatozoa, rate of forward movement, debris, primary abnormalities and secondary abnormalities. The isolation procedure consisted of layering 2 ml of diluted semen (100 x 10(6) spermatozoa/ml) over 6 ml of 3% BSA in 13 x 125 mm columns in a water bath (37 degrees C). After 30 min., the top semen layer and upper half of the BSA layer were withdrawn from all columns and the lower half of the BSA was re-evaluated. A 2 x 2 factorial arrangement of treatments was utilized with either the inclusion or omission of calcium or fatty acids in the BSA isolation media. The percent motile spermatozoa and rate of forward movement were increased (P<.01) when fatty acids were included in the isolation media but decreased (P<.01) when they were omitted. The highest percent motile spermatozoa and rate of forward movement were observed with BSA in the presence of fatty acids and omission of calcium. The calcium by fatty acid interaction, stallion effect and stallion by treatment interaction were significant for percent motile spermatozoa. Less debris was observed in all samples of isolated spermatozoa when compared with the initial estimate. Isolation resulted in a reduction of (P<.01) the primary abnormalities. Also, fewer (P<.01) secondary abnormalities were observed after isolation in all treatments except 4 (-FA+Ca) than were found in the ejaculate sample.     

Excess nuclear DNA in spermatozoa of guinea fowl

The proportion of spermatozoa with elongated nuclei in ejaculates from a strain of guinea fowl was estimated, subjectively, to range from approximately 1 to 6%. It was confirmed by image analysis that in an ejaculate from one male, the distribution of nuclear lengths was bimodal, with a distinct population comprising 10% of spermatozoa having a mean nuclear length that was 52% greater than that of the remaining 90%. Furthermore, the mean DNA content of the 'large-nuclei' population was 1.85 times (not significantly different from twice) that of the main sperm population. The proportion of large-nuclei spermatozoa that was motile was less than that of normal sperm (31% versus 59%) and the velocity of motile spermatozoa was also less (24 microm/s versus 72 microm/s). The poor motility of the large-nuclei spermatozoa in vitro was reflected in their limited performance in vivo, since only 1.1% were found associated with the egg outer perivitelline layer. This is the first report to quantify the occurrence of, presumed, polyploid spermatozoa in a domestic bird. The incidence of such spermatozoa in commercial guinea fowl and other domestic poultry and the genesis and effects on fertility of such spermatozoa may be significant.