Atypical Centriolar Composition Correlates with Internal Fertilization in Fish

CP110 and CEP135 Localize Near the Proximal Centriolar Remnants of Mice Spermatozoa

Centrioles form centrosomes that organize microtubules, assist in cell structure, and nucleate cilia that provide motility and sensation. Within the sperm, the centrosome consists of two centrioles (proximal and distal centriole) and a pericentriolar material known as the striated column and capitulum. The distal centriole nucleates the flagellum. Mice spermatozoa, unlike other mammal spermatozoa (e.g., human and bovine), have no ultra-structurally recognizable centrioles, but their neck has the centriolar proteins POC1B and FAM161A, suggesting mice spermatozoa have remnant centrioles. Here, we examine whether other centriolar proteins, CP110 and CEP135, found in the human and bovine spermatozoa centrioles are also found in the mouse spermatozoa neck. CP110 is a tip protein controlling ciliogenesis, and CEP135 is a centriole-specific structural protein in the centriole base of canonical centrioles found in most cell types. Here, we report that CP110 and CEP135 were both located in the mice spermatozoa neck around the proximal centriolar remnants labeled by POC1B, increasing the number of centriolar proteins found in the mice spermatozoa neck, further supporting the hypothesis that a remnant proximal centriole is present in mice.

Fermentation of Plant-Based Feeds with Lactobacillus acidophilus Improves the Survival and Intestinal Health of Juvenile Nile Tilapia (Oreochromis niloticus) Reared in a Biofloc System

This study evaluated the effect of fermentation with Lactobacillus acidophilus on the biochemical and nutritional compositions of a plant-based diet and its effects on the productive performance and intestinal health of juvenile Nile tilapia (Oreochromis niloticus) reared in a biofloc technology (BFT) system. The in vitro kinetics of feed fermentation were studied to determine the L. acidophilus growth and acidification curve through counting the colony-forming units (CFUs) mL-1 and measuring the pH. Physicochemical and bromatological analyses of the feed were also performed. Based on the microbial growth kinetics results, vegetable-based Nile tilapia feeds fermented for 6 (FPB6) and 18 (FPB18) h were evaluated for 60 days. Fermented diets were compared with a positive control diet containing fishmeal (CFM) and a negative control diet without animal protein (CPB). Fermentation with L. acidophilus increased lactic acid bacteria (LAB) count and the soluble protein concentration of the plant-based feed, as well as decreasing the pH (p < 0.05). FPB treatments improved fish survival compared with CPB (p < 0.05). Fermentation increased feed intake but worsened feed efficiency (p < 0.05). The use of fermented feeds increased the LAB count and reduced pathogenic bacteria both in the BFT system's water and in the animals' intestines (p < 0.05). Fermented plant-based feeds showed greater villi (FPB6; FPB18) and higher goblet cell (FPB6) counts relative to the non-fermented plant-based feed, which may indicate improved intestinal health. The results obtained in this study are promising and show the sustainable potential of using fermented plant-based feeds in fish feeding rather than animal protein and, in particular, fishmeal.

The evolution of centriole degradation in mouse sperm

Centrioles are subcellular organelles found at the cilia base with an evolutionarily conserved structure and a shock absorber-like function. In sperm, centrioles are found at the flagellum base and are essential for embryo development in basal animals. Yet, sperm centrioles have evolved diverse forms, sometimes acting like a transmission system, as in cattle, and sometimes becoming dispensable, as in house mice. How the essential sperm centriole evolved to become dispensable in some organisms is unclear. Here, we test the hypothesis that this transition occurred through a cascade of evolutionary changes to the proteins, structure, and function of sperm centrioles and was possibly driven by sperm competition. We found that the final steps in this cascade are associated with a change in the primary structure of the centriolar inner scaffold protein FAM161A in rodents. This information provides the first insight into the molecular mechanisms and adaptive evolution underlying a major evolutionary transition within the internal structure of the mammalian sperm neck.

Structural Analysis of Sperm Centrioles Using N-STORM

A prominent technical barrier when imaging swimming sperm is capturing a singular sperm cell's head and tail position simultaneously at a high resolution to understand their relationship in different stages of the sperm tail beating cycle. This is due to the sperm's high beating frequency, rotational movement, and the large difference in diameter between the head and tail. These intricacies increase the complexity of determining the position of a dynamic subcellular structure in the sperm neck, such as the centriole. We have developed a way to obtain this information by snap freezing mobile sperm at different stages of the sperm tail beating cycle and then analyzing them with super-resolution microscopy. This method captures the position of both the sperm head and tail at the microscale and centriolar substructure details at the nanoscale. This chapter describes the detailed procedures for the selection, preparation, antibody staining, 3D N-STORM imaging, and image quantification of bovine spermatozoa.

On the Origin and Evolution of Sperm Cells

Sperm cells have intrigued biologists since they were first observed nearly 350 years ago by Antonie van Leeuwenhoek and Johan Ham [...].

The Centriole's Role in Miscarriages

Centrioles are subcellular organelles essential for normal cell function and development; they form the cell’s centrosome (a major cytoplasmic microtubule organization center) and cilium (a sensory and motile hair-like cellular extension). Centrioles with evolutionarily conserved characteristics are found in most animal cell types but are absent in egg cells and exhibit unexpectedly high structural, compositional, and functional diversity in sperm cells. As a result, the centriole’s precise role in fertility and early embryo development is unclear. The centrioles are found in the spermatozoan neck, a strategic location connecting two central functional units: the tail, which propels the sperm to the egg and the head, which holds the paternal genetic material. The spermatozoan neck is an ideal site for evolutionary innovation as it can control tail movement pre-fertilization and the male pronucleus’ behavior post-fertilization. We propose that human, bovine, and most other mammals–which exhibit ancestral centriole-dependent reproduction and two spermatozoan centrioles, where one canonical centriole is maintained, and one atypical centriole is formed–adapted extensive species-specific centriolar features. As a result, these centrioles have a high post-fertilization malfunction rate, resulting in aneuploidy, and miscarriages. In contrast, house mice evolved centriole-independent reproduction, losing the spermatozoan centrioles and overcoming a mechanism that causes miscarriages.