A simple method for preparing meiotic chromosomes from mammalian testis

Freshly removed testis tubules are treated with hypotonic citrate solution and fixed in 31 acetic alcohol without undue rupture. The material is transferred to 60% acetic acid and the resulting suspension is air-dried onto warm slides using a micropipette. Finally the slides are stained with lacto-acetic orcein. — Provided suitable storage is made, slides need not be prepared in the same week as fixation and this may facilitate the collection of material during field study.     

A simple method for observation of phagocytosis on bacterial thin-layer

A simple method was developed to visually present the phagocytic activity of leukocytes by using adherent Staphylococcus aureus cells and blood applied on a plastic dish. When heparinized blood was applied on thin-layer of heat-killed S. aureus cells on the plastic dish, plaques due to the phagocytic activity of leukocytes were observed with a microscope under a low magnification. Fewer and smaller plaques were observed when plasma-deprived rather than whole blood was used. Some analyses were made in respect to the fundamental conditions required for optimal results. This method was considered to be useful for conveniently evaluating the serum opsonin activities and phagocytic function of leukocytes in various kinds of diseases.     

A simple method for high resolution banding of chromosomes in amniotic fluid cells

Summary A simple technique which results in good quality early mitotic stages of amniotic fluid (AF) cells is presented. Two days after trypsinization AF cell cultures are incubated for 4 h in culture medium containing 20 U/ml liquemin. During the last hour 5 g/ml ethidium bromide (EB) is added and 15 min before harvest 0.04 g/ml colcemid is applied as usual. G-banded and Q-banded chromosomes corresponding to at least 550–850 bands per haploid genome can be obtained in sufficient numbers.     

A method for linking yeast artificial chromosomes.

A method for linking any standard yeast artificial chromosomes (YAC) is described. YACs are introduced into the same cell and joined by mitotic recombination between the vector arms and the homologous sequence in a linking vector; several YACs can be recombined sequentially. The linking vectors also contain the beta-galactosidase gene as an expression reporter in mammalian cells.     

A simple and rapid method for visualization of male meiotic chromosomes in Arabidopsis thaliana

Meiotic chromosomes are of basic interest to the geneticist and cell biologist who study their behavior. A rapid and highly repeatable method for visualization of meiotic chromosomes is useful. Here we describe a fast staining protocol for Arabidopsis male meiotic chromosomes. Meiocytes were squashed into a labeling buffer, the chromosome morphology could be analyzed using fluorescence without any additional treatment.     

A rapid, simple and reliable combined method for G-banding mammalian and human chromosomes

A simple and reliable method for G-banding chromosomes from human and mammalian cells is described. This rapid method combines hot saline and trypsin treatments and yields high quality G-bands in both bone marrow and cultured cells.     

A simple procedure for obtaining autoradiographs of G-banded chromosomes

Chromosomal preparations from cells flash-labeled with ³H-dT were Giemsa-banded following trypsin digestion, allowed to air-dry, and then were coated with a layer of 1% Formvar. The slides were subsequently coated with radiographic emulsion (NTB2) and processed for autoradiography. The resulting chromosomes had distinct G-banding and radiographic labeling patterns. Chemographic grain formation in the emulsion, normally caused by Giemsa stain, was prevented by the film of Formvar, allowing a very low background grain level.     

A simple method for global sequence comparison.

A simple method of sequence comparison, based on a correlation analysis of oligonucleotide frequency distributions, is here shown to be a reliable test of overall sequence similarity. The method does not involve sequence alignment procedures and permits the rapid screening of large amounts of sequence data. It identifies those sequences which deserve more careful analysis of sequence similarity at the level of resolution of the single nucleotide. It uses observed quantities only and does not involve the adoption of any theoretical model.     

A simple method for rat endotracheal intubation.

A simple, fast, reliable, and atraumatic method of endotracheal intubation was developed to provide long-term mechanical ventilation in rats. Light from a focused point source directed to the outside of the skin just anterior to the pharyngoepiglottic region penetrated the skin, muscles and trachea and allowed direct visualized placement of an endotracheal tube.     

A simple banding technique for identification of human metaphase chromosomes

Summary A simple technique of Giemsa staining is described giving characteristic banding patterns of human metaphase chromosomes; these patterns can be used to identify all 24 chromosome types.

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Zusammenfassung Wir beschreiben eine einfache Methode, die mit geringem Zeitaufwand charakteristische Bandenmuster in menschlichen Metaphase-Chromosomen ergibt. Die Muster ermöglichen die Identifizierung aller 24 Chromosomentypen.

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Director: Prof. Dr. W. Fuhrmann

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Supported by the Deutsche Forschungsgemeinschaft and the Sonderforschungsbereich 35.     

寇氏隐甲藻（Crypthecodinium cohnii）染色体的提取及其独特的超 …

In this paper, a new method of extracting the dinoflagellate Crypthecodinium cohnii chromosomes was proposed. The ultrastructure of dinoflagellate Crypthecodinium cohnii chromosome was studied by transmission electron microscope. The chromosome fibres of dinoflagellate fold in a different manner from that of typical eukaryotes.     

A new method for the preparation of mammalian spermatogonial chromosomes.

After the seminiferous tubules were minced and washed with phosphate-buffered saline to remove sperms, spermatids and spermatocytes (Hoo and Bowles, 1971), they were repeatedly treated with 0.1% trypsin solution to liberate spermatogonia. It was concluded that the spermatogonial chromosomes can be analysed much more easily and accurately by this procedure than by previous ones.     

A simple method to sequentially reveal Q- and C-bands on the same metaphase chromosomes

The Q-C staining procedure, i.e., to treat QM stained preparations with a modified ASG method, conveniently provides Q? and C? (instead of the expected G?) bands on the same metaphase chromosomes. This procedure is especially useful for karyological study of heteroploid cells and interspecific cell hybrids in which extensive chromosomal rearrangements and complex karyotypic compositions are present. A few examples of karyological interest are reported. C-bands, which are either Q+ or Q?, can be divided into two to three subsegments in human chromosomes 1, 9, and 16. These subsegments are connected by a Q?/C?element. Interstitial C-bands could have originated mostly from a C-band without the kinetochore or with the“non-functional” kinetochore.“Double Minutes” are of two kinds, Q+/C+ and Q?/C+. Mechanism for the production of C-bands by the Q-C procedure is briefly discussed.     

A simple method for DNA restriction site mapping.

When a DNA molecule, enzymatically labelled with 32p at one end, is partially digested with a restriction enzyme labelled tdna fragments are obtained which form an overlapping series of molecules, all with a common labelled terminus. ta restriction map can then be constructed from an analysis of the size distribution of these molecules. This technique has been used for the restriction site mapping of cloned histone DNA (h22) where as many as 35 cleavage sites may be accurately determined in a single experiment.     

A simple method for the preparation of fish chromosomes applicable to field work, teaching and banding

A method is described which has broad application for field acquisition of fish karyotypes for research and teaching. The benefits of the method include: low initial skill level, relatively inexpensive equipment and supplies, simplicity and speed, and the high quality of preparations. The technique was applied to a field study of Apogon maculatus which was shown to contain 34 chromosomes, 2 nucleolar organizing regions (NOR's), and resolvable G-bands.