simple-efficient-technique-for-preparation-testicular-cell

Simple and Efficient Technique for the Preparation of Testicular Cell Suspensions

Mammalian testes are very complex organs that contain over 30 different cell types, including somatic testicular cells and different stages of germline ...

Instituto de Investigaciones Biológicas Clemente Estable

The interphase nucleus structure is radially organised into three-dimensional discrete chromosome territories or domains (CTs) surrounded by a channel network named the interchromatin compartment (IC) which harbours factors involved in DNA replication or repair as well as RNA transcription and processing. Gene-rich chromosomes are centrally located whereas gene-poor ones are bound to the nuclear outskirts. Chromatin dynamics also reflect nuclear compartment organisation. Replication timing and topology as well as active or inactive chromatin residence are highly regulated in eukaryotic cells. Early replicating euchromatin, high transcription levels and histone H4 hyperacetylation (H4+a) characterise the nuclear interior while late replicating heterochromatin, poor transcription rates and underacetylated histone H4 distinguish the nuclear periphery. Active chromatin loops mostly map to the surface of CTs and protrude into the IC whereas inactive loops mainly reside in the CTs core. Response of nuclear compartments to clastogen insult in terms of chromosomal aberrations is not uniform. The euchromatic, H4+a nuclear interior seems more sensitive to ionising radiation, nucleases and chemical agents. Topological changes of CTs occur after induced radiation damage. Chromatin remodeling associated to DNA synthesis, CTs relative positioning, loci spatial proximity, intermingling of chromatin loops and transcriptional activity could be critical to determine chromosome damage localisation, genomic instability and cancer-prone translocation frequencies.

Nuclear architecture, chromosome domains and genetic damage.

Homogeneity of cell populations is a prerequisite for the analysis of biochemical and molecular events during male gamete differentiation. Given the complex organization of the mammalian testicular tissue, various methods have been used to obtain enriched or purified cell populations, including flow cell sorting. Current protocols are usually time-consuming and may imply loss of short-lived RNAs, which is undesirable for expression profiling. We describe an optimized method to speed up the preparation of suitable testicular cell suspensions for cytometric analysis of different spermatogenic stages from rodents. The procedure takes only 15Â min including testis dissection, tissue cutting, and processing through the Medimachine System (Becton Dickinson). This method could be a substitute for the more tedious and time-consuming cell preparation techniques currently in use.

Ultra-fast and optimized method for the preparation of rodent testicular cells for flow cytometric analysis.

This collection of articles was inspired by the long-standing relationship between the Environmental Mutagen Society and Latin American scientists, and by the program for the 39th Environmental Mutagen Society meeting in Puerto Rico in 2008, which included a symposium featuring "South of the border" scientists. This collection, compiled by Graciela Spivak and Ofelia Olivero, both originally from Argentina, highlights scientists who work in or were trained in Latin American countries and in Puerto Rico in a variety of scientific specialties related to DNA repair and cancer susceptibility, genomic organization and stability, genetic diversity, and environmental contaminants.

Impact of EMS outreach: successful developments in Latin America.

Chromosomes, genomes and beyond. Preface.

Laudatio MÃ¡ximo E. Drets.

Mammalian spermatogenesis is still nowadays poorly understood at the molecular level. Testis cellular heterogeneity is a major drawback for spermatogenic gene expression studies, especially when research is focused on stages that are usually very short and poorly represented at the cellular level such as initial meiotic prophase I (i.e., leptotene [L] and zygotene [Z]). Presumably, genes whose products are involved in critical meiotic events such as alignment, pairing and recombination of homologous chromosomes are expressed during the short stages of early meiotic prophase. Aiming to characterize mammalian early meiotic gene expression, we have found the guinea pig (Cavia porcellus) as an especially attractive model. A detailed analysis of its first spermatogenic wave by flow cytometry (FCM) and optical microscopy showed that guinea pig testes exhibit a higher representation of early meiotic stages compared to other studied rodents, partly because of their longer span, and also as a result of the increased number of cells entering meiosis. Moreover, we have found that adult guinea pig testes exhibit a peculiar 4C DNA content profile, with a bimodal peak for L/Z and P spermatocytes that is absent in other rodents. Besides, we show that this unusual 4C peak allows the separation by FCM of highly pure L/Z spermatocyte populations aside from pachytene ones, even from adult individuals. To our knowledge, this is the first report on an accurate and suitable method for highly pure early meiotic prophase cell isolation from adult mammals, and thus sets an interesting approach for gene expression studies aiming at a deeper understanding of the molecular groundwork underlying male gamete production.

Gustavo A. Folle

Servicio de Citometría de Flujo y Clasificación Celular (SECIF)

Instituto de Investigaciones Biológicas Clemente Estable

Simple and Efficient Technique for the Preparation of Testicular Cell Suspensions