细胞功能测定

The electrophoretic mobility shift assay (EMSA) determines sequence-specific protein-deoxyribonucleic acid (DNA) interactions (e.g., transcription factors with cognate regulatory elements). This assay is based on reduced electrophoretic mobilities of protein/DNA ...

Mapping DNase I hypersensitive sites can often localize the control regions in a eukaryotic gene. It is generally believed that chromosomal regions with loose or more open conformation are sensitive to DNase I cleavage. By comparing the patterns of hypersensitive sites obtained by diges ...

Ligation-mediated polymerase chain reaction (LM-PCR) is used for high-resolution genomic footprinting. This technique was originally developed to study in vivo protein-deoxyribonucleic acid (DNA) interactions at regions of genes important for transcriptional regula ...

Apoptosis, or programmed cell death, refers to both the initiation and execution of the events whereby a cell commits suicide. This process is important in development and its deregulation is found in many diseases (1–6), including cancer (6–10). Apoptosis is distinct from other ways in which ce ...

Malignant tumors are composed of cells that have lost their proliferation control and multiply independently of a physiologic need for increase in cell number in the tissue. Cells that have lost these proliferative controls are often referred to as “transformed.” Transformation of a mam ...

Alkylating agents are a series of potentially carcinogenic compounds that are able to introduce lesions into deoxyribonucleic acid (DNA; ref. 1). For their electrophilic nature, alkylating agents have an affinity for the nucleophilic centers of DNA and are monofunctional (have one re ...

Apoptosis plays a critical role in important biological processes such as morphogenesis, tissue homeostasis, and elimination of genomic damaged or virally infected cells and of self-reactive clones from the immune system (1). Although apoptosis is important during normal develo ...

γ Radiation is an electromagnetic radiation with wavelengths in the range of 0.1–100 pm. Like all forms of electromagnetic radiations, the γ ray has no mass and no charge and interacts with material by colliding with the electrons in the shells of atoms. Irradiation with γ rays is very penetrating, and t ...

The genera of the retroviridae comprise oncoretroviruses and lentiviruses (1). Oncoretroviruses can only infect dividing cells, as they require the breakdown of the nuclear membrane to access the cellular chromosomal deoxyribonucleic acid (DNA; ref. 2). Conversely, lentivirus ...

Ultraviolet (UV) radiation is mutagenic in a wide variety of organisms and is a major source of physical deoxyribonucleic acid (DNA) damage. The mutations caused and the biological consequences of exposing cell cultures to UV light have been extensively studied and have given many insights ...

With this method, antibiotic selection of the infected cells gives rise to a countable number of colonies after 7–10 d (1–4). Other reporter genes are based on green fluorescent protein (GFP; ref. 5) or the Escherichia coli lacZ gene, which encodes for β-galactosidase for X-gal staining (4,6). GFP-ex ...

The assessment of the viral titer is an important step in optimizing and reproducing working conditions for the gene transduction for various mammalian cell types. The assessment of the viral titer is an important parameter to determine the maximum number of target cells that can be infected f ...

Immunocytochemistry is the most diffuse technique to visualize and localize specific biochemical components in cell compartments and tissues. With this method the antigens are tagged by antibodies that can be visualized with appropriate markers attached directly (direct met ...

The fluorescence labeling technique is a method with a high degree of specificity and sensitivity and is often chosen as a tool in the study of protein expression and subcellular compartments (1). Recently, a large number of fluorescent dyes with distinct fluorescence excitation and emiss ...

Mammalian spermatogenesis is a highly organized process of cell division and differentiation that requires intimate contact between germ cells and testicular somatic cells. Lack of a suitable in vitro system has caused many aspects of spermatogenesis, especially in nonrodent spe ...

Spermatogonial stem cells (SSCs) produce sperm throughout the post-pubertal life of a male. Transgenic loss- and gain-of-function mouse models have shown that their self-renewal and differentiation are controlled in vivo by glial-cell-line-derived neurotrophic factor (GDNF) ...

Germ cells constitute the vehicles of genetic information and thereby of inheritance through generations. The epigenetic control mechanisms that govern maintenance and reprogramming of the germline in diverse organisms have gained increasing interest as they reveal essent ...

The different types of spermatogonia present in the testes of all mammalian species have a series of functions in the adult testis. Some cycle regularly to (1) maintain the spermatogonial population and (2) derive differentiating germ cells to maintain continuous spermatogenesis; oth ...

It is possible to distinguish the morphological features of the spermatogonial nuclei and nucleoli and to further identify their distinct generations using an appropriate method to fix whole testes via vascular perfusion with glutaraldehyde, postfixation by immersion in reduc ...

Knowing the structure opens a door for a better understanding of function because there is no function without structure. Male germline stem cells (GSCs) of the milkweed bug (Oncopeltus fasciatus) exhibit a very extraordinary structure and a very special relationship with their niche, the ...