Characteristics of the base composition of mitochondrial ribosomal RNA.
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Adenine Nucleotides↗
Biomedical subjects
B Bartoov
Publications and source records attributed to B Bartoov.
Synthesis of ribonucleic acid by isolated rat liver mitochondria.
Rat liver mitochondria isolated in sucrose-N-tris(hydroxymethyl)methyl-2-aminoethane-sulphonic acid (TES) incorporated [(3)H]UTP into RNA for 1h. Incorporation was inhibited 50% by 1mug of actinomycin D/ml, 1mug of acriflavine/ml and 0.5mug of ethidium bromide/ml but was insensitive to rifampicin, rifamycin SV, streptovarcin and deoxyribonuclease. After the first 10min of incubation, the synthesis was insensitive to ribonuclease. RNA synthesis by mitochondria isolated in sucrose-EDTA was insensitive to actinomycin D and sensitive to ribonuclease during the first 10min of the incubation but thereafter the sensitivities were the same as for mitochondria isolated in sucrose-TES. In a hypo-osmotic medium the relative extent of incorporation of the four ribonucleoside triphosphates into RNA was CTP>UTP=ATP>>GTP. In an iso-osmotic medium the incorporation of CTP and GTP decreased. All four nucleotides were incorporated into RNA in a DNA-dependent process, as indicated by the inhibition by actinomycin D. In addition, CTP and ATP were incorporated into the CCA end of mitochondrial tRNA. ATP was also incorporated into an unidentified acid-insoluble compound, which hydrolysed in alkali to a product that was not ATP, ADP or 5'- or 2(3')-AMP. Atractyloside inhibited the incorporation of ATP into RNA with 50% inhibition at 2-3nmol/mg of protein. The [(3)H]UTP-labelled RNA had peaks of 16S and 13S characteristic of mitochondrial rRNA. In addition a peak at 20-21S was observed as well as heterogeneous RNA sedimenting throughout the gradient. The synthesis of all these species was inhibited by actinomycin D, indicating that rat liver mitochondrial DNA codes for mitochondrial rRNA as well as other as yet unidentified species.
Acridines↗
Comparison of mammalian mitochondrial ribosomal ribonucleic acid from different species.
Mitochondrial ribosomal RNA species from mouse L cells, rat liver, rat hepatoma, hamster BHK-21 cells and human KB cells were examined by electrophoresis on polyacrylamide-agarose gels and sedimentation in sucrose density gradients. The S(E) (electrophoretic mobility) and S values of mitochondrial rRNA of all species were highly dependent on temperature and ionic strength of the medium; the S(E) values increased and the S values decreased with an increase in temperature at a low ionic strength. At an ionic strength of 0.3 at 23-25 degrees C or an ionic strength of 0.01 at 3-4 degrees C the S and S(E) values were almost the same being about 16.2-18.0 and 12.3-13.6 for human and mouse mitochondrial rRNA. The molecular weights under these conditions were calculated to be 3.8x10(5)-4.3x10(5) and 5.9x10(5)-6.8x10(5), depending on the technique used. At 25 degrees C in buffers of low ionic strength mouse mitochondrial rRNA species had a lower electrophoretic mobility than those of human and hamster. Under these conditions the smaller mitochondrial rRNA species of hamster had a lower electrophoretic mobility than that of human but the larger component had an identical mobility. Mouse and rat mitochondrial rRNA species had identical electrophoretic mobilities. Complex differences between human and mouse mitochondrial rRNA species were observed on sedimentation in sucrose density gradients under various conditions of temperature and ionic strength. Mouse L-cell mitochondrial rRNA was eluted after cytoplasmic rRNA on a column of methylated albumin-kieselguhr.
Animals↗
The synthesis of ribosomal-type RNA by isolated rat liver mitochondria.
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Acridines↗
Ribosomal-type ribonucleic acid from rodent mitochondria.
1. Highly purified mitochondria containing 3.0mug of RNA/mg of mitochondrial protein were prepared from rat liver by differential centrifugation. 2. RNA, labelled with [(32)P]P(i) or [(3)H]orotate, was isolated from these mitochondria by a phenol extraction method. The RNA sedimented at 15S and 13S on sucrose density gradients. Its nucleotide composition was 23% uridylate, 30% adenylate, 22% guanylate and 25% cytidylate. 3. RNA from mouse L cells was labelled with [(3)H]-uridine in the presence of 0.1mug of actinomycin D/ml to suppress the synthesis of cytoplasmic rRNA. The RNA isolated from crude L-cell mitochondria by a cold-phenol-sodium dodecyl sulphate method had components sedimenting at 15S and 12.5S. These components had an electrophoretic mobility on agarose-acrylamide gels of 21 and 12S(E) compared with 28 and 18S(E) for cytoplasmic rRNA. The nucleotide composition was 26% uridylate, 34% adenylate, 18% guanylate and 22% cytidylate. 4. RNA extracted from crude L-cell mitochondria by a hotphenol-sodium dodecyl sulphate method had an additional component sedimenting at 21S and having an electrophoretic mobility of 18S(E). It was probably DNA because of its sensitivity to deoxyribonuclease and its insensitivity to ribonuclease and alkali. It was present in nuclear fragments contaminating the crude mitochondrial fraction and could be removed by deoxyribonuclease or isopycnic-gradient centrifugation.
Adenine↗
Quantitative ultramorphological analysis of human sperm: fifteen years of experience in the diagnosis and management of male factor infertility.
The advantages of quantitative ultramorphological (QUM) sperm analysis in the diagnosis and treatment of male infertility are presented. The QUM methodology is based on three elements: complementary scanning electron microscopy and transmission electron microscopy observations of 7 sperm cell subcellular organelles (acrosome, postacrosomal lamina, nucleus, neck, axoneme, mitochondrial sheath, and outer dense fibers); systematic classification of the specific ultramorphological malformations into 4 pathological and the normal categories, indicating the morphological state of each subcellular organelle; and comparison between well-defined reference groups with opposite fertility status or treatment conditions. QUM has established 2 indices for the in vivo and in vitro male fertility potential: (1) Natural Fertility Index (NFI), with accurate prediction (97% sensitivity and 90% specificity) of 80% of the male patients; and (2) IVF score, with prediction of 76% of the nonfertilizing and 90% of fertilizing IVF groups. QUM has enabled assessment of ultramorphological indications for varicocele and radiation exposure. Varicocele causes defects in sperm head organelles related to early spermatid development, whereas ionizing radiation causes amorphous head shape. QUM established criteria for specific non-in-vitro therapeutic interventions, including varicocelectomy, follicle-stimulating hormone (FSH) administration, and acupuncture. The varicocele index enabled correct classification of 79 and 89% of patients with and without varicocele. Males with idiopathic impairment of sperm acrosome and nucleus are potential responders to FSH treatment, whereas patients exhibiting low sperm activity are candidates for acupuncture treatment. Patients with a low Natural Fertility Index are recommended for an assisted reproduction technique (ART). based on the ultramorphology of the tail axoneme. Patients who achieved pregnancy following intrauterine insemination or in vitro fertilization and those whose wives conceived only following intracytoplasmic sperm injection were classified with accuracy of 78 and 74%, respectively. QUM sperm analysis is clinically informative, nontraumatic, and cost-effective, and is recommended when the male infertility factor cannot be clearly diagnosed by routine tests prior to first ART trial.
Cell Nucleus↗
Quantitative ultramorphological (QUM) analysis of human sperm: diagnosis and management of male infertility.
The advantages of quantitative ultramorphological (QUM) sperm analysis in the diagnosis and treatment of male infertility are presented. QUM methodology is based on three elements: (1) complementary SEM and TEM observations of 7 sperm cell subcellular organelles: acrosome, postacrosomal lamina, nucleus, neck, axoneme, mitochondrial sheath, and outer dense fibers; (2) systematic classification of the specific ultramorphological malformations into 4 pathological and the normal categories, which indicate the morphological state of each subcellular organelle; and (3) comparison between well-defined reference groups with opposite fertility status or treatment conditions. QUM analysis has enabled the establishment of two indices that optimally express the in vivo and in vitro male fertility potential: The Natural Fertility Index (NFI), which allowed an accurate prediction (97% sensitivity and 90% specificity) of 80% of the naturally fertile and suspected infertile male patients, and the in vitro fertilization (IVF) score, which enabled prediction of 76% of the nonfertilizing and 90% of the fertilizing IVF groups. Validation tests confirmed these data. QUM also enabled assessment of ultramorphological indications for varicocele and radiation exposure: Both male factor etiologies indicated a persistent effect on the natural fertility potential, as expressed by structural changes in the nucleus. Varicocele was found to cause defects in the sperm head organelles related to early spermatid development, whereas ionizing radiation resulted in amorphous head shape. Criteria for specific non-in vitro therapeutic interventions such as varicocelectomy, follicle-stimulating hormone (FSH) administration, and acupuncture treatment were established. A varicocele index, which enabled the correct classification of 79 and 89% of the patients pre- and post-high ligation, respectively, was suggested to be a good indicator for varicocele which affects the fertility potential. Males exhibiting idiopathic impairment of sperm acrosome and nucleus were found to be potential responders to FSH treatment, whereas patients exhibiting low sperm activity proved to be good candidates for acupuncture treatment. Indications for selecting the optimal appropriate assisted reproduction technique (ART) procedure were found: Patients with a low Natural Fertility Index should be recommended for ART. A first choice ART selection should be performed according to an ART index based on the ultramorphological examination of the tail axoneme. The above index enabled correct prediction of 78% of the patients who achieved pregnancy following conventional ART (intrauterine insemination or IVF) and 74% of those whose wives conceived only following intracytoplasmic sperm injection. QUM sperm analysis is clinically informative, nontraumatic, and in the long run also cost-effective. This analysis should be performed when the male infertility factor cannot be clearly diagnosed by routine tests and prior to the first ART trial.
Acrosome↗
Separation of sub-populations of sperm with higher fertility potential from normal and pathological semen by peanut agglutinin.
Incubation of human sperm from semen with counts below 20 x 10(6)/ml with peanut agglutinin (PNA) resulted in agglutination of about 70% of sperm. An inverse correlation was found between non-agglutinating (PNA) sperm and sperm density (r = 0.48, p less than 0.01) and a direct correlation with acrosome-damaged sperm (r = 0.83, p less than 0.001). Binding of 125I-PNA to sperm revealed high, and possibly also low affinity binding sites on sperm from both normozoospermic and oligozoospermic origins. Quantitative transmission electron microscopy analysis revealed that agglutinated, PNA+, sperm had lower frequency of acrosomeless spermatozoa than PNA(-)-sperm (44% versus 77%) and higher fertility score (+0.18 +/- 0.1 and -1.5 +/- 0.87 respectively, p less than 0.01). Removal of PNA- sperm from oligozoospermic semen may increase the fertility score of the remaining sperm.
Cell Separation↗
Virulence characteristics of male genital tract Escherichia coli isolated from semen of suspected infertile men.
The role of Escherichia coli isolates from the semen in the etiology of male infertility, was investigated in this study. Several possible virulence factors of E. coli, such as possession of O antigens or certain K antigens (K1, K5), the type of fimbriae, resistance to antimicrobial drugs and adherence studies to various mammalian sperm cells were examined. It was found that out of 181 E. coli isolates 76.4% belonged to four different urinary serotypes: O1, O2, O4 and O6 (5.7%, 7.5%, 17.0% and 46.2%, respectively). The predominant fimbrial phenotype (81.2%) was T1F+/P-, while 15.8% showed also the possession of P fimbriae (T1F+/P+). No isolate was found with the T1F-/P+ phenotype. The possession of antigens K1, K5 was found to be low (12% only). A relatively high level of adherence to different mammalian sperm cells was found among E. coli isolates. 43% of the E. coli isolates were resistant to doxycycline (the drug of choice) and additionally, most of these were resistant also to ampicillin. We suggest that there is a close subpopulation of E. coli which possess certain virulence properties and have the potential to adhere to sperm cells and to colonize on other target tissues in the male genital tract. Such virulent may cause asymptomatic male infertility and may be termed male genital tract (MGT)-E. coli.
Animals↗
Sperm head ultramorphology and chromatin stability of males with unexplained infertility who fail to fertilize normal human ova in vitro.
An in vitro nuclear chromatin decondensation test, and quantitative nuclear ultramorphology analysis, were performed on 18 males judged to be infertile, by two failures in in vitro fertilization, and 16 fertile males. These two clinical groups only differed significantly in (1) the direction of their chromatin stability change, which took place 30-120 min post-ejaculation while stored in the seminal plasma, and (2) in the incidence of the hypoelongated sperm-head. Generally, the fertile male group exhibited positive chromatin stability change after prolonged storage, and low incidence of hypoelongated sperm heads, and vice versa in the unexplained infertile group. When the nuclear chromatin decondensation test and quantitative ultramorphology analysis were performed in step-wise fashion, it was possible to correctly classify 94% of the fertile cases with 6% of false-negative, and 89% of the unexplained infertile cases with 11% of false-positive. Therefore, it appears that these tests might be of benefit clinically for identifying functional properties of sperm-cells in unexplained infertile males, which cannot be detected by routine semen analysis.
Cell Nucleus↗
Human sperm acrosin activity with relation to semen parameters and acrosomal ultrastructure.
It was suggested that although not related to the standard semen parameters the level of the acrosin enzyme system is related to the fertility potential in men. Recently a simple clinical assay for total acrosin level was recommended for routine semen analysis. The improved clinical assay was analysed on the freshly liquified semen of 198 Asthenoteratozoospermic men and compared with the routine semen parameters including biochemical data and the ultrastructure of the acrosome. Only the sum of the per cent of live, motile, and normal-shaped spermatozoa had positive significant and reasonably high correlation with the acrosin level (r = 0.382, P < 0.0001). Each characteristic exhibits significant but low (< 0.35) correlation. Similarly negative significant and reasonably high correlation was obtained between the acrosin level and the sum of the principle acrosomal malformations observed by TEM (r = 0.396, P < 0.0001) while lower negative correlation was found only with agenesis or loss of the acrosome. Acrosin levels below 8.1 microIU 10(-6) cells were obtained in 4 specimens with above 80% round-form associated with more than 95% of agenesis of the acrosome. The possible significance of the low correlation obtained between the acrosin levels and seminal plasma zinc levels, malformations in the acrosomal equatorial region, and the presence of white blood cells is also discussed. We concluded that the acrosin activity reflects an aspect of male fertility which is not diagnosed by the routine semen analysis or by the ultrastructure of the acrosome, and is therefore a useful diagnostic sperm parameter.
Acrosin↗
Relation of human sperm acrosin activity and fertilization in vitro.
The aim of the study described here was to determine the possible contribution of the acrosin activity test to routine semen analysis in enhancing the precision of the prognosis of IVF success in a group of patients in which the contribution of the egg factor to infertility was ruled out (20 cases) compared to a control IVF group (39 cases). Semen analysis, acrosin activity and acrosome ultrastructure were determined for all semen samples. The group with high fertilization rates was comprised of normozoospermic patients while the group with low fertilization rates was comprised of astheno-teratozoospermic patients. The mean acrosin level of the positive IVF group was significantly higher than that of the negative group (51.7 +/- 33.2 and 28.6 +/- 13.7, respectively). Two parameters: per cent motile spermatozoa and acrosin level, were found to have a significant positive correlation with subsequent successful IVF (r = 0.36, P < 0.006; r = 0.37, P < 0.004, respectively); and agenesis of the acrosome was found to have a significant negative correlation (r = -0.33, P < 0.01). The ability of these parameters to correctly predict fertilization success was 59%, with 5% false positive, among which 15.4% was predicted solely by the acrosin level (above 54 microIU 10(6) cells-1) and 23% solely by per cent motile spermatozoa (above 50%). Abnormalities of the acrosome ultrastructure did not contribute further to the correct classification. The apparent clinical benefit of the acrosin level test is discussed.
Acrosin↗
The relationship between ejaculated ram sperm mitochondrial protein synthesis and motility.
D-chloramphenicol, at concentrations of 20 and 40 micrograms/ml, inhibited over 80% of the newly synthesized mitochondrial proteins expressed by incorporation of 3H-amino acid mixture. At concentrations of 20 and 40 micrograms ml-1, D-chloramphenicol enhanced the collective motility of washed ram spermatozoa. The collective motility measured by the multichannel Reflectospermiograph system, significantly enhanced the motility wave frequencies and amplitudes by 24-17% and 65-32%, respectively. Furthermore, the longevity of the collective motility was prolonged by 12-19%. In about 20% of the cases, when the original sperm motility was low, it was found that 40 micrograms ml-1 D-chloramphenicol has maximum stimulation effect on sperm motility in inverse fashion. Since the mitochondria are located adjacent to the motility initiation area, it can be speculated that the mitochondrial protein(s) directly inhibiting the axonemal-ATPase activity or indirectly blocking sperm metabolite, are essential for maintaining sperm motility.
Adenosine Triphosphatases↗
Age-related ultramorphologic sperm abnormalities among salvage workers from the Chernobyl nuclear power plant.
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Adult↗
Effect of acupuncture on sperm parameters of males suffering from subfertility related to low sperm quality.
The aim of this prospective controlled study was to assess the effect of acupuncture on the sperm quality of males suffering from subfertility related to sperm impairment. Semen samples of 16 acupuncture-treated subfertile patients were analyzed before and 1 month after treatment (twice a week for 5 weeks). In parallel, semen samples of 16 control untreated subfertile males were examined. Two specimens were taken from the control group at an interval of 2-8 months. The expanded semen analysis included routine and ultramorphological observations. The fertility index increased significantly (p < or = .05) following improvement in total functional sperm fraction, percentage of viability, total motile spermatozoa per ejaculate, and integrity of the axonema (p < or = .05), which occurred upon treatment. The intactness of axonema and sperm motility were highly correlated (corr. = .50, p < or = .05). Thus, patients exhibiting a low fertility potential due to reduced sperm activity may benefit from acupuncture treatment.
Acrosome↗
Dual energy metabolism-dependent effect of Ureaplasma urealyticum infection on sperm activity.
Genital Ureaplasma urealyticum infection is considered a sexually transmitted infection. It has long been debated whether the presence of U. urealyticum in semen may be a possible cause of infertility. Long-term incubation (4 hours or overnight) of sperm cells with U. urealyticum in vitro resulted in a significant inhibition of sperm motility and membrane alteration whereas a short incubation (45 minutes) of sperm cells with ureaplasmas resulted in an acceleration of sperm velocity. The aim of this study was to understand these contradictory reports of U. urealyticum infection on sperm motility. Spermatozoa from fresh ejaculates of normozoospermic semen of men who were referred to the university Male Fertility Laboratory for semen analysis, with no history of genital tract infection, and from normal Assaf breed rams were infected in vitro with U. urealyticum serotype 8, at different pHs and O2 concentrations. Sperm viability and motility and changes in extracellular pH were evaluated. A significant (16%-43%) increase in sperm activity was observed upon infection at alkaline pH (7.8) under aerobic or hypoxic conditions, and a 58% increase was observed under anaerobic conditions and pH 7.2. When the infection was conducted under aerobic conditions and acidic pH (6.3), or under hypoxic conditions at neutral pH (7.2), an 8%-25% inhibition of sperm activity was observed. These results indicate that when sperm activity depends on mitochondrial oxidative phosphorylation, usually at low pHs, U. urealyticum competes with mitochondrial energy production and therefore reduces sperm motility and viability. However, when sperm energy metabolism depends on glycolysis, usually at higher pHs, U. urealyticum stimulates glycolysis and sperm activity.
Anaerobiosis↗