Cytogenetic studies in some species of Passiflora L. (Passifloraceae): a review emphasizing Brazilian species

The Passifloraceae is represented by species of tropical and subtropical origin. The Passiflora is the richest genus with approximately 450 species, 200 of them being native to Brazil. Recent karyological studies have reported the basic chromosome number for the Passiflora genus as x = 6, whereas x = 9, x = 10 and x = 12 were established as secondary basic numbers. High rates of fertility occur in most Passiflora species, since both meiotic index and pollen viability are above 90 percent. Unusual meiotic behavior has been described in some taxa. Unviable pollen were observed in some diploids species. The genome size varies from 1.83 to 5.36 pg, and significant interspecific variance has been observed. Studies using the FISH methodology have shown that there are two to three rDNA 45S sites and one 5S site in the species analyzed. In this review, information about the above-mentioned studies is presented and discussed in detail.

A família Passifloraceae é representada por espécies de origem tropical e subtropical. Passiflora é o gênero mais rico, com aproximadamente 450 espécies, cerca de 200 delas nativas do Brasil. Recentes estudos cariológicos têm relatado o número básico de cromossomos para o gênero Passiflora como sendo x = 6, enquanto x = 9, x = 10 e x = 12 foram considerados números básicos secundários. Altas taxas de fertilidade são observadas na maioria das espécies de Passiflora, uma vez que o índice meiótico e a viabilidade polínica apresentam-se acima de 90 por cento.Comportamento meiótico irregular tem sido descrito para alguns taxas. Grãos de pólen inviáveis foram observados em espécies diplóides. O tamanho do genoma varia de 1,83 a 5,36 pg, e variação interespecífica significativa tem sido observada. Estudos usando a metodologia de hibridização in situ (FISH) tem demonstrado haver de dois a três sites de DNAr 45S e um site de DNAr 5S nas espécies analisadas. Nesta revisão, informações sobre os estudos acima mencionados são apresentados e discutidos em detalhes.

Relationship between DAPI-fluorescence fading and nuclear DNA content: An alternative method to DNA quantification?

In observations by confocal or conventional fluorescence microscopy, important factors should be considered in order to obtain accurate images. One of them, such as the fluorescence bleaching from highest intensity to lowest signal of fluorescence is a common problem with several DNA fluorochromes and especially for DAPI stain. The fluorescence of DAPI fades rapidly when it is exposed to UV light, under optimal conditions of observation. Although the fading process can be retarded using a mounting medium with antifading reagents, the photochemical process underlying the fluorescence decay has not yet been fully explained. In addition, no relationship between fluorescence fading and nuclear DNA content has been tested. In order to test this relationship, we measured by means of image analysis the DAPI-fluorescence intensity in several cellular types (spermatozoa, erythrocytes and haemocytes) during their fluorescence bleaching. An algorithm specifically built in MATLAB software was used for this approach. The correlation coefficient between nuclear DNA content and DAPI-fluorescence fading was found equal to 99 percent. This study demonstrates the feasibility to measure nuclear DNA content by fluorescence fading quantification, as an alternative method concurrently with image analysis procedures.

The Changes of Histopathology, Proliferation Activity, and Nuclear DNA Content N-butyl-N-(4-hydroxybuty1) Nitrosamine(BBN) Induced Bladder Cancer in Rats / 대한비뇨기과학회지

To evaluate the process of tumor progression in chemical carcinogenesis of the bladder cancer. 0.05% BBN was administered to female Wistar rats for 12 weeks. The rats were divided into six groups and sacrificed every or every two weeks from the 12th to the 20th weeks. Cellular touch imprints of urinary bladder for DNA content analysis by image analyzer and mean AgNORs count per nucleus were performed immediately after sacrifice. Thereafter, the urinary bladder was embedded in paraffin for histopathological examination.On histopathological findings, simple hyperplasia was found in all cases after 12 weeks therapy of BBN. Atypical hyperplasia of the bladder, indicative of a precancerous state, was found in 88.9% of the 12 weeks group, 83.3% of the 13 weeks and in all cases after 14 weeks therapy of the BBN. Bladder cancer was found in 33.3% of the 13 weeks, 55.6% of the 14 weeks, and 100% of the above 16 weeks therapy group. The nuclear DNA content of 21 cases of atypical hyperplasia was diploid in 19 cases(91.5%) and aneuploid in 2 cases(9.5%). DNA aneuploidy was found in 18 cases(66.7%) among the 27 cases of the cancer group. Mean AgNORs count per nucleus and proliferation index by flowcytometry were higher in atypical hyperplasia and cancer group than these of simple hyperplasia and control group, but those differences according to histologic type were not statistically significant. And there was statistically significant correlation between proliferation index and mean AgNORs count per nucleus(r=0.57, p<0.05). These data suggest that the change of nuclear DNA content might occur during the early phase of the carcinogenesis in BBN-induced bladder cancer of rats.

The relationship between nuclear DNA content and the expressions of cyclin D1 and P53 proteins in carcinogenesis of breast carcinoma induced by DMBA in rats / 第三军医大学学报

Objective To investigate the interrelation between nuclear DNA content and the expressions of cyclin D1 and P53 in carcinogenesis of breast carcinoma induced by 7,12 dimethylbenz(a)anthracence(DMBA) in rats. Methods Animal model of breast carcinoma was replicated by gastric perfusion of DMBA at 20 mg/100 g. Nuclear DNA content was detected with image analysis instrument and the expressions of cyclin D1 and P53 at every stage of carcinogenesis of breast carcinoma induced by DMBA in rats observed by Sp immunohistochemical staining. Results In mammary gland tissue at grade Ⅰ, grade Ⅱ and grade Ⅲ atypical hyperplasia of breast carcinoma, there was overepression of cyclin D1(3/20, 6/20 and 11/20, respectively). The overexpression of cyclin D1 was detected to be present in grade Ⅰ, grade Ⅱ and grade Ⅲ breast carcinoma (7/9, 1/4 and 0/7, respectively). The overexpression of P53 was detected to be present in grade Ⅰ, grade Ⅱ and grade Ⅲ breast carcinoma (1/9, 1/4 and 6/7, respectively). Conclusion Nuclear DNA content reflects the state of cell proliferation. Cyclin D1 overexpression participates in the carcinogenesis of breast carcinoma, which may be the early event in breast carcinoma. P53 expression is associated with the development of breast carcinoma, which may be the late event in breast carcinoma. The expression of cyclin D1 is negatively correlated with P53 overexpression.

Molecular organization of great millet (Sorghum vulgare) DNA.

Approximately 52% of the nuclear genome of great millet (Sorghum vulgare) consists of repetitive DNA which can be grouped into very fast, fast and slow components. The reiteration frequencies of the fast and slow reassociating components are 7000 and 92 respectively. Approximately 90% of the genome consists of repeated sequences interspersed amongst themselves and with single copy sequences. The interspersed repeat sequences are of three sizes viz. > 1·5 kilobase pairs, 0·5–1·0 kilobase pairs and 0·15–0·30 kilobase pairs while the size of the single copy sequences is 3·0 kilobase pairs. Hence the genome organization of great millet is essentially of a mixed type.