High-resolution HKG-banding in maize mitotic chromosomes

Abstract

Root-Up maize chromosomes (2n= 20) were prepared by high-resoluUon procedures after ethidlum bromide/ colchlcine synchronization. Using HKG-banding (HCl-KOH-Glemsa), that shows both centromerlc and intercalary heterochromatin, the banding pattern of the elongated-chromosomes showed one to nine well-resolved dark bands. Differences of HKG-banding pattern of elongated and compacted chromosomes were performed by image analysis. Key words: Heterochromatin m High-resolution m HKG-banding m Image analysis ~ Maize chromosomesFrom a cytological viewpoint, two heterochromatin patterns have been revealed by banding procedures in maize root-tip chromosomes-the (1) knob heterochromatin and the (2) centromeric and intercalary heterochromatin. The first, was shown as a pronounced dark stained band by the C-banding technique (Carlson 1988), and the second, as distinct bands by HKG banding procedures (Carvalho and Saraiva 1993).According to Carvalho and Saraiva (1993), one to five HKG-bands were revealed in different chromosome sizes of the metaphasic set as well as in other phases of mitosis, suggesting differences of band numbers in relation to size and/or condensation of chromosomes.Improved technical achievements in banding chromosomes have added a new dimension to increasing band resolution. It is a well-documented fact that less condensed chromosomes display more bands. As a result, several methods to produce cytogenetic preparations with a large proportion of elongated chromosomes have been described, allowing greater accuracy in traditional karyo-type analysis on extended chromosomes in human and other vertebrates (Sumner 1990, Spowart 1994, Verma and Babu 1995.Little progress has been made in developing high-resolution banding procedures in plant. However, good elongated-chromosome preparations were obtained in celery (Murata and Orton 1984), Triticum (Zhu eta/. 1986), maize (Kakeda et a/. 1990) and Vicia faba (Belyayev 1993).

Chromosome banding and essential oils composition of Brazilian accessions of Lippia alba (Verbenaceae)

“…The Voucher specimens (Table 1) were deposited in the CESJ Herbarium, located in the Universidade Federal de Juiz de Fora -UFJF. For each chemotype identification, the essential oils from fresh leaves were obtained through hydrodistillation by a Clevenger-type apparatus during 2 h. The GC-MS analyses were performed on a Shimadzu gas chromatograph equipped with Supleco DB-5 column using helium as a carrier gas and 200 • C (3 h) and the slides were prepared according to Carvalho & Saraiva (1993, 1997. For meiotic analysis, the anthers were collected and fixed in a 3:1 methanol: acetic acid solution for at least 24 h and the slides were prepared according to Viccini et al (2005).…”

Karyotype with 210 chromosomes in guaraná (Paullinia cupana ‘Sorbilis’)

“…The slides were prepared by the cellular dissociation of apical meristems and air-drying techniques. The slides were stained with Giemsa 5% solution in phosphate buffer (pH 6.8) for 5 min, washed twice in distilled water, and air-dried at 50°C, as described by Carvalho and Saraiva (1997).…”

Nuclear DNA content and karyotype of Rosewood (Aniba rosaeodora)

“…The root tips were washed in distilled water for 20 min, fixed (3x) in 3:1 methanol:acetic acid and stored at -20°C. The cytogenetic preparations were proceeded by cellular dissociation of the apical meristem (Carvalho and Saraiva, 1997) and then left to dry at room temperature before staining with 5% Giemsa solution in phosphate buffer (pH 6.8) for 5 min, washing twice in distilled water and drying at 50°C.…”