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When sperm heads are injected into rat oocytes at the germinal vesicle stage the sperm heads remain intact until the germinal vesicle breaks down. Then they decondense but do not form pronuclei. This observation agrees with the results reported for in vitro fertilization of immature oocytes from rats, mice and hamsters.
The present report describes a simple and rapid procedure to isolate highly purified sperm heads from mouse, rat and rabbit. The isolation procedure involves mincing of the caput epididymidis (CPE) of mice and rats to obtain a crude CPE suspension. This suspension is filtered to remove tubular fragments. The filtrate containing sperms and cellular contaminants is trypsinized, followed by sonication. To obtain rabbit sperm head suspension, ejaculated spermatozoa are briefly exposed to the cationic detergent CTAB-D, followed by trypsinization. Trypsin treatment of the suspension yields sperm heads and tails. The suspension containing sperm heads and tails is separated by discontinuous sucrose density gradient centrifugation. Highly purified and enriched sperm heads are recovered from the bottom of 2.5 M sucrose of the gradient. Enriched sperm heads contain less than 1% sperm tails.
The volumes of sperm heads were estimated from three-dimensional reconstructions of serially sectioned bundles of nearly mature spermatid nuclei. Cysts from males in which all sperm are expected to have comparable amounts of chromatin (X/Y and 1n(3LR)/+) show unimodal frequency distributions of nuclear volumes, whereas cysts from males in which meiotic segregation is expected to deliver unequal amounts of chromatin material to spermatid nuclei show two (XY/O and XY/Y) or more (T(2;3)/+ ANd C(2L);C(2R)) modes. The mean volumes of the subpopulations in these cases are related in the same proportions as the metaphase lengths of their chromosomal complements. Thus the volumes of sperm nuclei are proportional to their DNA content. Sperm head shape, on the other hand, does not appear to be very sensitive to chromosomal constitution, as heads of different size do not vary greatly in shape.----The numbers of sperm heads in the various size classes in a cyst depart from mendelian expectations; these departures are caused by the elimination, during individualization, of chromosomes contained within micronuclei that are formed in spermatids at the end of the second meiotic division. The effect of this chromosome loss is to increase the proportion of nullosomic gametes in the sperm pool.----The relative frequencies of XY-bearing and nullo-X, nullo-Y sperm in XY/O males were estimated from the volume measurements. Taking this estimate as a measure of the fertilizing population, it is possible to infer from the change in sex ratio over time following insemination, that XY-bearing sperm have an advantage of 1.5 over nullo-X, nullo-Y sperm in leaving the seminal receptacle of the female for fertilization of ova.
OBJECTIVE: To explore the clinical phenotype and genetic etiology of a male with Multiple morphological abnormalities of sperm flagella (MMAF) combined with sperm head abnormalities due to compound heterozygous variants of DNAH1 gene, with an aim to provide guidance for assisted reproductive technology in his family. METHODS: A man with MMAF combined with sperm head abnormalities who visited Women and Children's Hospital of Ningbo University in October 2024 was selected as study subject. Clinical data of the patient's family were retrospectively collected. Peripheral blood samples were collected from the patient and his spouse, and G-banding karyotyping and whole exome sequencing (WES) were carried out. Candidate variants were validated by Sanger sequencing. Conservation of the DNAH1 protein was queried on the UCSC website. The difference between wild type and variant DNAH1 proteins were analyzed using AlphaFold v3.0.1 and PyMOL v2.5.6. The pathogenicity of variant was rated based on the guidelines from American College of Medical Genetics and Genomics (ACMG). Previous literature was searched using keywords "DNAH1 gene" and "multiple morphological abnormalities of the sperm flagella" on CNKI, Wanfang Data Knowledge Service Platform, and PubMed database to identify cases of MMAF attributed to biallelic DNAH1 gene variants. The retrieval period was set from the establishment of the databases to December 31, 2025. The genotypes and clinical phenotypes of patients with biallelic DNAH1 mutations were analyzed. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: EC2023-094). RESULTS: The 30-year-old patient and his 30-year-old wife had infertility for 2 years. Semen analysis revealed no motile sperm and a 99.0% abnormal morphology rate. Typical MMAF was observed with phase-contrast microscopy. Sperm morphology analysis revealed abnormalities of the head, neck, and tail with an approximate ratio of 9:5:1. The patient's karyotype was 46,XY, and his wife's karyotype was 45,X[4]/47,XXX[1]/46,XX[84]. WES and Sanger sequencing revealed that the patient harbored compound heterozygous variants of the DNAH1 gene, namely c.1435_1444+3del and c.12204_12206del (p.Asn4069del), but their origin remained unidentified. UCSC genome browser query results showed that the amino acid residue at position 4 069 of the DNAH1 protein is highly conserved across various species. Protein structure prediction reveals that, in the wild-type DNAH1 protein, the Asparagine at position 4 069 (Asn4069) can form hydrogen bonds with the Leucine on the main chain at position 4 086 (Leu4086) and the Serine on the side chain at position 4 087 (Ser4087). The c.12204_12206del variant, resulting in deletion of Asn4069, disrupts these hydrogen bonds and does not generate any compensatory interactions. Based on the ACMG guidelines, the c.1435_1444+3del variant was predicted to be likely pathogenic (PM2_Supporting+PVS1), and the c.12204_12206del(p.Asn4069del) variant was rated as likely pathogenic (PM2_Supporting+PM4+PM3+PP4). The couple had elected for in vitro fertilization using donor sperm. During this cycle, 12 oocytes were retrieved, 10 oocytes were successfully fertilized, 1 embryo and 6 blastocysts were obtained. Following the first transfer of a frozen-thawed blastocyst, implantation of an empty gestational sac occurred, which led to a miscarriage. After the second transfer of a high-quality blastocyst, the embryo split into twins following implantation, and the spouse had selected fetal reduction. The gestational age was 33+3 weeks on June 1, 2026. Literature review identified three studies reporting biallelic mutations of the DNAH1 gene in association with MMAF combined with sperm head abnormalities. Together with the patient from this study, a total of 20 patients were included in the analysis. The rate of sperm flagellar abnormalities in these patients was above 80.0%, while the rate of sperm head abnormalities has ranged from 12.0% to 100.0%. In four patients, the genetic basis was unknown. In the remaining 16 patients, 35 mutations were detected, with c.8626-1G>A being the most common (22.9%, 8/35). CONCLUSION: This patient showed MMAF with frequent sperm head defects. Compound heterozygous variants of the DNAH1 gene probably underlay these abnormalities, which in turn has led to his primary infertility. This study revealed the phenotypic variability of MMAF and broadened the mutational spectrum of the DNAH1 gene.
It is generally accepted that at least some Y chromosomes in human mature sperm heads are represented in preparations by fluorescent F-bodies. From data consisting solely of F-body scorings and the visually estimated size of sperm heads from normal donors, a quantitative model is developed which permits simultaneous estimation of six parameters representing biological factors (the proportions of ploidy classes and of their sex-chromosome complements) and biassing factors (not all Y chromosomes represented by F-bodies, not all F-bodies representing Y chromosomes, and error in scoring ploidy from visual size). The analysis is statistically adequate and succeeds in predicting a variety of independently validated phenomena. The work may be regarded as a contribution to the integration of qualitative and quantitative evidence in the study of F-bodies. In all, 21,700 one-headed spermatozoa from 12 donors were scored. A mean of 54% spermatozoa lacking F-bodies was subject to a standard deviation between donors of 4.8, over and above binomial error. Analysis yielded the following estimates: 83.3% of diploid spermatozoa are XY, the remainder XX and YY in assumed equal number (this information assists analysis of the origin of embryonic triploidy); 2.4% of spermatozoa are diploid (this estimate does not compete in accuracy with direct estimates from DNA absorbance); only 83% of Y chromosomes are represented by F-bodies; 7% of haploid heads and 14% of diploids contain one or more "adventitious bodies" indistinguishable from true F-bodies. The visually scored head sizes "Small" and "Medium" correspond approximately with haploidy and diploidy; nearly all haploids are scored as Small, and 72% of the Medium are diploid. F-bodies are not thought at present to give a useful basis for estimating the presumably low incidence of sex-chromosome aneuploidy and nondisjunction. No such estimate has been attempted. The problem is overshadowed by not fully understood complicating factors of greater magnitude, which now appear to be a major subject of enquiry. Some implications and possible future developments are discussed.
Galline, a protamine of domestic fowl, was obtained by two preparation procedures from the semen of a strain of White Plymouth Rock and submitted to fractionation by column chromatography on Bio-Gel CM-30. In the first procedure the specimen prepared from sperm heads was purified by the use of distilled water and dilute acetic acid and fractionated into almost eight fractions (G-I-G-VIII) in the same way as the specimen from a strain of New Hampshire (1,2). No difference could be found between galline specimens from the two different strains based on the amino acid and terminal analyses of each fraction. The specimen of galline from sperm heads purified with 1% citric acid (the second procedure) was composed of only one component, which was isolated as a single peak. The smaller fractions, G-I-G-VII, were found to be derived from G-VIII by the action of trypsin-like protease contained in the extract of sperm heads with 1% citric acid. This enzyme seems to originate in the acrosome of fowl spermatozoa. Consequently, it is concluded that intact galline is composed of only one molecular species and its total amino acid sequence is represented by the completed formula of G-VIII as shown in the preceding paper (4).
Semen samples from 14 sandhill cranes were collected for 15 weeks. Mean sperm head length which did not vary significantly over weeks was found to be significantly correlated with fertility (P less than 0 . 04; r = 0 . 54, n = 14).
Two specially shaped sample injection tubes orient flat-shaped mature sperm heads in a flow cytometer. Orientation allows control of a photometric difficulty experienced with some flow cytometers in the measurement of fluorescent and scattered light from sperm and other flat cells. Both relative DNA-stain content and a measure of cell flatness can now be determined simultaneously for each cell at the high rates possible with flow instruments.
BACKGROUND: Macrozoospermia is a rare form of teratozoospermia characterized by tetraploids, large-headed spermatozoa with multiple flagella, usually caused by bi-allelic AURKC mutations. The etiology of atypical phenotypes with a lower proportion of large headed spermatozoa and single flagella however often remains unresolved. OBJECTIVE: To investigate the genetic cause of severe sperm-head abnormalities with moderate macrozoospermia without multiflagellated spermatozoa in a patient with repeated ICSI failure. An infertile male with three failed ICSI attempts underwent semen analysis, revealing complete teratozoospermia, including 25% macrocephalic spermatozoa. METHODS: Multi-probe FISH targeting chromosomes 13, 18, 21, X, Y assessed chromosomal segregation. Whole-exome sequencing (WES) was performed to identify a candidate variant associated with meiotic abnormalities. RESULTS: FISH analysis revealed a high proportion of spermatozoa with n (23) chromosomes and 2c DNA content, consistent with sister chromatid non-disjunction during meiosis II. WES identified a homozygous missense variation in CCNA1, coding for a protein described to be essential for meiotic progression and chromatin remodeling in male germ cells. DISCUSSION: The variant affects a highly conserved residue within a functional domain and is predicted to be deleterious. This study establishes the first clinical association between CCNA1 mutations and chromatid non-disjunction in human spermatogenesis. It highlights the limitations of current morphology-based diagnostic thresholds and supports cytogenetic and genomic assessment for severe teratozoospermia (especially head abnormalities) and ART failure. CONCLUSION: Expanding genetic screening panels to include CCNA1 may improve diagnostic precision and clinical management in atypical macrozoospermia cases.
The mean surface area of the head of fixed and stained spermatozoa from 12 healthy, young donors was measured on 3 occasions separated by 8-day intervals. The mean area varied appreciably between individuals, and considerably less between samples from the same donor.
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Myosin was extracted and partially purified from the head portion of spermatozoa of the starfish, Asterias amurensis. The sperm myosin showed a specific Ca2+-activated ATPase [EC 3.6.1.3] activity of 0.2 mumoles Pi/min/mg at high ionic strength and pH 6.5. It resembled egg myosin in forming thick filaments, becoming attached to actin filaments. subunit composition, and serological properties.
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Ejaculated spermatozoa from man, the Euopean wild boar and the bull, and spermatozoa from the cauda epididymes of the rabbit, rat, mouse, hamster and Guinea pig were treated with a sonic bath, a sonic probe, trypsin with and without prior treatment with a sulphhydryl reagent, pronase and alkalis. The fragments produced were counted and sized in an accurately calibrated Coulter Counter, Model ZB Industrial, before and after Zaponin treatment to lyse accompanying debris and the peripheral cytoplasm. Head and tail fractions were separated on sucrose gradients. Each species required different conditions for cleavage or fragmentation. Rabbit and bull spermatozoa were cleaved by the ultrasonic bath exactly into heads and tails, producing twice the number of particles with two peaks in the size distribution curves butith some 60% loss of total sperm volume which became the soluble fraction. The ultrasonic probe, and for the bull, pronase, produced the same cleavage but these more drastic treatments dissolved a considerable portion of the tail fraction. Rodent spermatozoa, especially the rat, were cleaved perfectly into heads and tails by mild trypsin treatment. All the nonrodent spermatozoa were resistent to trypsin cleavage, although prior treatment with a sulphhydryl reagent caused swelling and subsequent trypsin action caused digestion into miscellaneous pieces. Spermatozoa from the boar and from man could not be cleaved by any of the procedures. The sonic probe produced fragmentation with progressive dissolution of the tail fragments and a single peak in the size distribution curve corresponding to small stripped heads. The soluble fraction always constituted a large proportion of the original whole spermatozoa.
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