Scientific Articles - Genetics/Genomics Feed

Combining ES Cells with Embryos

Fri, 10 Apr 2026 22:00:49 +0000

The marvel of embryonic stem (ES) cells is that after in vitro culturing and genetic modification, they still have the ability to contribute to the developing embryo, when combined with pre-implantation embryos, to produce chimeras and even completely ES cell-derived animals. In this chapter, we will describe three methods for combining ES cells with embryos: the injection of ES cells into blastocysts, the injection of ES cells into eight-cell stage embryos and aggregation of ES cells with morulae. To date, blastocyst injection is the most commonly used method, adopted by core facilities rather than individual laboratories, partially because of the high cost of equipment and long training period required, prohibitive to some labs. The Injection of eight-cell stage embryos can be performed using the same equipment, but because fewer cells are injected per embryo this method is faster and can be learned quickly by anyone trained in blastocyst injection. The procedure makes use of less expensive outbred embryo donor mice and produces completely ES cell-derived mice when good quality ES cells are used. Morula aggregation is performed under a simple dissecting stereomicroscope, thereby lowering the startup costs, and requires a shorter training period. Although the procedure utilizes less expensive outbred strains of mice as embryo donors, the savings are partially offset by the need for larger numbers of transferred embryos per female due to the lower implantation rate of the zona pellucida (ZP) free embryos. On the other hand, morula aggregations are much faster and easier to perform than microinjections and similar to eight-cell microinjections they often result in fully ES cell-derived animals.

Source: http://www.springerprotocols.com/Abstract/doi/10.1007/978-3-642-20792-1_17

Advanced Microscopy: Laser Scanning Confocal Microscopy

Fri, 10 Apr 2026 22:00:49 +0000

Fluorescence microscopy is an important and fundamental tool for biomedical research. Optical microscopy is almost non-invasive and allows highly spatially resolved images of organisms, cells, macromolecular complexes, and biomolecules to be obtained. Generally speaking, the architecture of the observed structures is not significantly modified and the environmental conditions can be kept very close to physiological reality. The development of fluorescence microscopy was revolutionized with the invention of laser scanning confocal microscopy (LSCM). With its unique three-dimensional representation and analysis capabilities, this technology gives us a more real view of the world.

This chapter introduces the reader to the methodology of setting up basic experiments for use with a laser scanning confocal microscope. There are practical guidelines about sample preparation for both fixed and living specimens, as well as examples of some of the applications of confocal microscopy.

Source: http://www.springerprotocols.com/Abstract/doi/10.1...

Visualizing Bacillus subtilis During Vegetative Growth and Spore Formation

Fri, 10 Apr 2026 22:00:49 +0000

Bacillus subtilis is the most commonly used Gram-positive bacterium to study cellular processes because of its genetic tractability. In addition, during nutrient limitation, B. subtilis undergoes the development process of spore formation, which is among the simplest examples of cellular differentiation. Many aspects of these processes have benefited from fluorescence microscopy. Here, we describe basic wide-field fluorescence microscopy techniques to visualize B. subtilis during vegetative growth, and the developmental process of sporulation.

Source: http://www.springerprotocols.com/Abstract/doi/10.1007/978-1-4939-3631-1_19