ABSTRACT
Somatic chromosome numbers are reported for thirty four germplasm accessions of Paspalum, Caespitosa group, representing five different species. All five species have shown x=10 as the basic chromosome number. The diploid 2n=20 chromosome number was confirmed for P. chacoense and P. indecorum, as well as sexuality for the latter. This is the first report of the chromosome number and cytological behavior for P. ligulare (2n=20 and 40), P. pleostachyum (2n=20, 30 and 40) and P. redondense (2n=20 and 40). The present results document regular meiosis in diploid accessions, with primarily bivalent pairing at diakinesis and metaphase I. Polyploids of these species had irregular meiosis, with univalent, trivalent, and quadrivalent chromosome associations. Diploid accessions of P. pleostachyum and P. ligulare have shown a single meiotic embryo-sac, indicating sexual reproduction, while the triploid and one of the tetraploid accessions of P. pleostachyum have shown aposporic embryo-sacs of nucelar origin, and a few meiotic sacs, suggesting facultative apomixis. Identification of the new diploid accessions may prove useful for phylogenetic studies of Paspalum, as well as for breeding programs focusing on the forage potential of species of the Caespitosa group.
Números cromossômicos são reportados para trinta e quatro acessos, representando cinco espécies de Paspalum, grupo Caespitosa. Todos são múltiplos do número básico x=10. Confirmou-se o número diploide 2n=20 para P. chacoense e P. indecorum como, também, a sexualidade para P. indecorum. As contagens cromossômicas são inéditas para P. ligulare (2n=20 e 40), P. pleostachyum (2n=20, 30 e 40) e P. redondense (2n=20 e 40). A meiose foi regular nos diploides, com pareamento em bivalentes na diacinese e metáfase I, enquanto irregularidades, tais como univalentes, trivalentes e quadrivalentes, foram comuns nos poliploides. Acessos diploides de P. pleostachyum e P. ligulare mostraram um único saco embrionário meiótico em cada óvulo, indicando reprodução sexual. O acesso triploide e um dos tetraploides de P. pleostachyum evidenciaram sacos apospóricos e alguns sacos meióticos, sugerindo apomixia facultativa. A identificação dos novos acessos diploides poderá se mostrar bastante útil para o estudo filogenético do gênero, assim como para programas de melhoramento genético focados no potencial forrageiro das espécies do grupo Caespitosa.
ABSTRACT
Chromosome numbers were counted in 126 new accessions of 50 Paspalum species from Brazil, Argentina, Paraguay and Bolivia. The chromosome numbers 2n=12, 20, 24, 30, 40, 50, 60, 80 were confirmed. Chromosome numbers for P. arenarium (2n=20), P. barretoi (2n=20), P. aff. ceresia (2n=40), P. corcovadense (2n=20), P. crispulum (2n=20), P. flaccidum (2n=40), P. nummularium (2n=20), P. scalare (2n=20), P. vescum (2n=20) and P. rectum (2n=20) and a diploid cytotype of P. malacophyllum are reported for the first time. The predominance of tetraploid accessions (43.6 percent) was confirmed, but an unusually high number of diploid species (44 percent) and accessions (35.7 percent) was found. These results open new perspectives for breeding programs, phylogenetic studies, and for research on apomixis control, since diploids of Paspalum are typically sexual.
O número cromossômico foi determinado para 126 novos acessos de 50 espécies de Paspalum do Brasil, Argentina, Paraguai e Bolívia. Foram verificados os números somáticos 2n=12, 20, 24, 30, 40, 50, 60 e 80. Estas são as primeiras contagens para P. arenarium (2n=20), P. barretoi (2n=20), P. aff. ceresia (2n=40), P. corcovadense (2n=20), P. crispulum (2n=20), P. flaccidum (2n=40), P. nummularium (2n=20), P. scalare (2n=20), P. vescum (2n=20) e P. rectum (2n=20). O nível diplóide (2n=20) é reportado pela primeira vez para P. malacophyllum. Os dados confirmam a predominância de acessos tetraplóides (43,6 por cento) no gênero e mostram um número incomumente elevado de espécies (44 por cento) e acessos diplóides (35,7 por cento). Estes resultados trazem novas perspectivas para programas de melhoramento, para estudos filogenéticos e para pesquisa orientada ao controle da apomixia, já que em Paspalum as plantas diplóides são tipicamente sexuais.
ABSTRACT
Nuclear DNA content was analysed by means of flow cytometric measurements in 103 patients with gastric carcinomas, using paraffin-embedded archival tissue. DNA aneuploidy was found in 40 cases (38.8%). The mean DNA index of aneuploid tumors was 1.45(range 1.13 to 2.37). No significant association between ploidy and either age, sex, tumor location, size, stage, growth pattern, or histologic type was found. However, the incidence of aneuploidy was higher in high grade carcinomas than in low grade carcinomas; the incidence of aneuploidy was 10%, 68.8%, and 45.8% for Grade II, III, and IV carcinomas, respectively, as compared with Grade I carcinomas which were all diploid. On statistical analysis, Abnormal cellular DNA content was significantly correlated with high histologic grade (P<0.005). Patients with aneuploid cancer (39.2%) had a poorer prognosis than those with diploid cancer (70.0%) based on (P<0.01). The 2-year survival rate for advanced gastric carcinoma. Therefore, DNA ploidy might be a useful prognostic factor in cases of advanced gastric cancer.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Aneuploidy , DNA, Neoplasm/analysis , Flow Cytometry , Follow-Up Studies , Stomach Neoplasms/geneticsABSTRACT
Flow cytometry analysis of DNA ploidy level and S-phase fraction (SPF) was carried out in 24 snap-forzen tissue specimens of ovarian carcinoma. The relationship of DNA ploidy level and SP-F with age,clinical stage, ascites, histologic type,pathological grade,lymphocyte infiltration and psammoma bodies was analyzed.Results showed that the relationship of DNA ploidy level and SPF with ascites and pathological grade was significant. Aneuploid portion and SPF in patients with ascites or pathological grade Ⅲ or Ⅱ were higher than those in patients with no ascites or pathological grade I. The author considers that DNA ploidy level and SPF of ovarian carcinoma can serve as a relatively independent objective index which reflects tumor's biological behaviours,and will be of great auxiliary value to early diagnosis and therapy of ovarian carcinoma.