Feature-based 3D+t descriptors of hyperactivated human sperm beat patterns

The flagellar movement of the mammalian sperm plays a crucial role in fertilization. In the female reproductive tract, human spermatozoa undergo a process called capacitation which promotes changes in their motility. Only capacitated spermatozoa may be hyperactivated and only those that transition to hyperactivated motility are capable of fertilizing the egg. Hyperactivated motility is characterized by asymmetric flagellar bends of greater amplitude and lower frequency. Historically, clinical fertilization studies have used two-dimensional analysis to classify sperm motility, despite the inherently three-dimensional (3D) nature of sperm motion. Recent research has described several 3D beating features of sperm flagella. However, the 3D motility pattern of hyperactivated spermatozoa has not yet been characterized. One of the main challenges in classifying these patterns in 3D is the lack of a ground-truth reference, as it can be difficult to visually assess differences in flagellar beat patterns. Additionally, it is worth noting that only a relatively small proportion, approximately 10-20% of sperm incubated under capacitating conditions exhibit hyperactivated motility. In this work, we used a multifocal image acquisition system that can acquire, segment, and track sperm flagella in 3D+t. We developed a feature-based vector that describes the spatio-temporal flagellar sperm motility patterns by an envelope of ellipses. The classification results obtained using our 3D feature-based descriptors can serve as potential label for future work involving deep neural networks. By using the classification results as labels, it will be possible to train a deep neural network to automatically classify spermatozoa based on their 3D flagellar beating patterns. We demonstrated the effectiveness of the descriptors by applying them to a dataset of human sperm cells and showing that they can accurately differentiate between non-hyperactivated and hyperactivated 3D motility patterns of the sperm cells. This work contributes to the understanding of 3D flagellar hyperactive motility patterns and provides a framework for research in the fields of human and animal fertility

Extending resolution within a single imaging frame

The resolution of fluorescence microscopy images is limited by the physical properties of light. In the last decade, numerous super-resolution microscopy (SRM) approaches have been proposed to deal with such hindrance. Here we present Mean-Shift Super Resolution (MSSR), a new SRM algorithm based on the Mean Shift theory, which extends spatial resolution of single fluorescence images beyond the diffraction limit of light. MSSR works on low and high fluorophore densities, is not limited by the architecture of the optical setup and is applicable to single images as well as temporal series. The theoretical limit of spatial resolution, based on optimized real-world imaging conditions and analysis of temporal image stacks, has been measured to be 40 nm. Furthermore, MSSR has denoising capabilities that outperform other SRM approaches. Along with its wide accessibility, MSSR is a powerful, flexible, and generic tool for multidimensional and live cell imaging applications.Fil: Torres García, Esley. Universidad Nacional Autónoma de México; MéxicoFil: Pinto Cámara, Raúl. Universidad Nacional Autónoma de México; MéxicoFil: Linares, Alejandro. Universidad Nacional Autónoma de México; MéxicoFil: Martínez, Damián. Universidad Nacional Autónoma de México; MéxicoFil: Abonza, Víctor. Universidad Nacional Autónoma de México; MéxicoFil: Brito Alarcón, Eduardo. Universidad Nacional Autónoma de México; MéxicoFil: Calcines Cruz, Carlos. Universidad Nacional Autónoma de México; MéxicoFil: Valdés Galindo, Gustavo. Universidad Nacional Autónoma de México; MéxicoFil: Torres, David. Universidad Nacional Autónoma de México; MéxicoFil: Jabloñski, Martina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Torres Martínez, Héctor H.. Universidad Nacional Autónoma de México; MéxicoFil: Martínez, José L.. Universidad Nacional Autónoma de México; MéxicoFil: Hernández, Haydee O.. Universidad Nacional Autónoma de México; MéxicoFil: Ocelotl Oviedo, José P.. Universidad Nacional Autónoma de México; MéxicoFil: Garcés, Yasel. Universidad Nacional Autónoma de México; MéxicoFil: Barchi, Marco. University of Rome Tor Vergata; ItaliaFil: D'Antuono, Rocco. Crick Advanced Light Microscopy Facility; Reino UnidoFil: Bošković, Ana. European Molecular Biology Laboratory; AlemaniaFil: Dubrovsky, Joseph G.. Universidad Nacional Autónoma de México; MéxicoFil: Darszon, Alberto. Universidad Nacional Autónoma de México; MéxicoFil: Buffone, Mariano Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rodríguez Morales, Roberto. No especifíca;Fil: Rendon Mancha, Juan Manuel. Universidad Autónoma del Estado de Morelos; MéxicoFil: Wood, Christopher D.. Universidad Autónoma del Estado de Morelos; MéxicoFil: Hernández García, Armando. Universidad Autónoma del Estado de Morelos; MéxicoFil: Krapf, Diego. University of Colorado; Estados UnidosFil: Crevenna, Álvaro H.. European Molecular Biology Laboratory; ItaliaFil: Guerrero, Adán. Universidad Autónoma del Estado de Morelos; Méxic

Extending resolution within a single imaging frame

The resolution of fluorescence microscopy images is limited by the physical properties of light. In the last decade, numerous super-resolution microscopy (SRM) approaches have been proposed to deal with such hindrance. Here we present Mean-Shift Super Resolution (MSSR), a new SRM algorithm based on the Mean Shift theory, which extends spatial resolution of single fluorescence images beyond the diffraction limit of light. MSSR works on low and high fluorophore densities, is not limited by the architecture of the optical setup and is applicable to single images as well as temporal series. The theoretical limit of spatial resolution, based on optimized real-world imaging conditions and analysis of temporal image stacks, has been measured to be 40 nm. Furthermore, MSSR has denoising capabilities that outperform other SRM approaches. Along with its wide accessibility, MSSR is a powerful, flexible, and generic tool for multidimensional and live cell imaging applications