El cariotipo de Paspalum cromyorrhizon diploide y tetraploide (Poaceae, Panicoideae, Paspaleae)

Paspalum cromyorrhizon Trin. ex Döll is a species adapted to low and humid fields, river and stream banks, throughout S Brazil, Uruguay and NE Argentine. Diploids (2n = 2x = 20) and tetraploids (2n = 4x = 40) from natural populations of P. cromyorrhizon from Corrientes (Argentina) were used to analyse the karyotype morphometry of both cytotypes. The chromosome count was performed using classical Feulgen staining. The karyotype of diploid P. cromyorrhizon has 20 metacentric chromosomes, while the tetraploid has a karyotype of 40 metacentric chromosomes. The total length of the chromosomal complement in diploids is 32.5 μm and in tetraploids 63.5 μm, the total monoploid chromosome length is 15.48 μm in diploids and 15.21 μm in tetraploids and both karyotypes are symmetrical. Karyotype analysis confirms the autopolyploid origin proposed for tetraploids.

Nuclear changes in oral mucosa of alcoholics and crack cocaine users

The effects of drugs of abuse on oral mucosa are only partly understood. The aims of the present study were to: (1) evaluate the frequency of nuclear changes in normal-appearing oral mucosa of alcoholics and crack cocaine users and (2) assess their association with cell proliferation rate. Oral smears were obtained from the border of the tongue and floor of the mouth of 26 crack cocaine users (24 males and 2 females), 29 alcoholics (17 males and 12 females), and 35 controls (17 males and 18 females). Histological slides were submitted to Feulgen staining to assess the frequency of micronuclei (MN), binucleated cells (BN), broken eggs (BE), and karyorrhexis (KR). A significant increase in the frequency of MN was observed in cells exfoliated from the tongue of crack cocaine users ( p = 0.01), and alcoholics showed a higher frequency of KR in cells obtained from the floor of the mouth ( p = 0.01). Our findings suggest that the use of crack cocaine induces clastogenic effects, whereas alcoholism is associated with higher degrees of keratinization in the floor of the mouth.

A Comparison of Ice Cold Water Pretreatment andα-Bromonaphthalene Cytogenetic Method for Identification ofPapaverSpecies

The plants belonging to many species in genus Papaver are very similar and have very small chromosomes that make identification very difficult. The study aimed to compare the effects ofα-bromonaphtalene and ice cold water pretreatment to identify chromosomes of Papaver species collected from different areas of Iranian West Azerbaijan and Turkish Van, Agri and, Hakkari provinces. The seeds were germinated in Jacobson trays at 24°C under continuous light. Thereafter, roots from 1.5 cm long plantlets were pretreated withαbromonaphtalene for 15, 30, and 45 min or at 0°C in ice cold water for 24 h before fixing, hydrolyzation, and feulgen staining. The ice cold water pretreatment was more appropriate and easy to determine chromosomes. Seeds from seven samples did not germinate. Sixty samples out of the rest of 62 samples were identified asP. pseudo orientale, one sample was identified asP. bracteatum, and another asP. orientale. This is the first study that used ice cold water to determine the chromosomes in papaver species. It is hoped that it will also facilitate to determine chromosome number and identify other papver species.

Karyotipic asymmetry of both wild and cultivated species of Pennisetum

This study aimed the establishment of the relation between karyotipic asymmetry values obtained for different accessions of both wild and cultivated species of Pennisetum from Germplasm Bank of Embrapa Gado de Leite/Juiz de Fora-Minas Gerais State, Brazil. Conventional cell cycle synchronization protocols and Feulgen staining method were used to obtain metaphases plates. The wild-type accessions corresponded to the species P. setosum (2n=6x=54), P. nervosum (2n=4x=36), and P. orientale (2n=4x=36), and the cultivated to P. purpureum (2n=4x=28) and P. glaucum (2n=2x=14). No significant difference was found for the total length of chromosomes (p>0.05) among the species. The analysis of intra-chromosomal asymmetry (A1) and inter-chromosomal asymmetry (A2) has shown that P. setosum has a tendency to chromosome asymmetry. P. nervosum, P. orientale, and P. purpureum have presented an intermediary level of asymmetry and P. glaucum, low asymmetry. Considering Stebbins criteria, the karyotype of P. glaucum and those from the three wild species fitted into the category 1A-symmetrical. With regard to P. purpureum, karyotypes of the accessions BAGs 54, 65 and 91 fitted into the category 2B and the other two genotypes (BAGs 63 and 75) fitted into the 1A. Comparison between the karyotype classification according to the inter- and intra-chromosomal asymmetry and Stebbins methodologies revealed that this last one alone was not able to detect small variations between karyotypes of the taxa closely related.