Search results for " ploidy"
showing 10 items of 19 documents
Gametic and somatic embryogenesis through in vitro anther culture of different Citrus genotypes
2015
Abstract: In vitro tissue culture represents a useful technique for advancing Citrus breeding and propagation. Among in vitro regeneration systems, anther culture is commonly used to produce haploids and doubled haploids for a fast-track producing homozygous lines, in comparison with the traditional self-pollination approach, which involves several generations of selfing. In addition, anthers culture can produce somatic embryos that can also be used for clonal propagation. In this study, two thermal shocks were applied to the anthers of six Citrus genotypes (two clementine and four sweet oranges), just after they were put in culture. The response obtained was different depending on the geno…
Autotetraploid Emergence via Somatic Embryogenesis in Vitis vinifera Induces Marked Morphological Changes in Shoots, Mature Leaves, and Stomata
2021
Polyploidy plays an important role in plant adaptation to biotic and abiotic stresses. Alterations of the ploidy in grapevine plants regenerated via somatic embryogenesis (SE) may provide a source of genetic variability useful for the improvement of agronomic characteristics of crops. In the grapevine, the SE induction process may cause ploidy changes without alterations in DNA profile. In the present research, tetraploid plants were observed for 9.3% of ‘Frappato’ grapevine somatic embryos regenerated in medium supplemented with the growth regulators β-naphthoxyacetic acid (10 µM) and N6-benzylaminopurine (4.4 µM). Autotetraploid plants regenerated via SE without detectable changes in the …
Flow cytometric DNA analysis and lysosomal cathepsins B and L in locally advanced laryngeal cancer. Relationship with clinicopathologic parameters an…
1995
Background. The traditional factors of locally advanced laryngeal squamous cell carcinoma (LSCC) have limited predictive value for the identification of high risk patients. Therefore, it is extremely important to define prognostic factors that identify the more aggressive types. Reliable and reproducible prognostic indicators are being investigated to help clinicians identify high risk groups and address more rational treatment. Methods. Flow cytometric DNA ploidy and S‐phase fraction (SPF) measurements were performed on frozen tumor tissues from a consecutive series of 71 patients with Stage III and IV LSCC. Lysosomal cathepsin B and L activity levels were determined biochemically in match…
Patterns of DNA-ploidy in operable colorectal carcinoma: A prospective study of 100 cases
1991
A prospective study of cellular DNA content was made by means of flow cytometry in a nonconsecutive series of 100 patients undergoing surgery for primary colorectal adenocarcinoma. DNA-aneuploidy was present in 80% of cases (80/100); 39% of these were multiclonal (31/80). There was no significant correlation between DNA-ploidy and the clinical and pathological features examined, except for the primary tumor site (right colon vs. left colon vs. rectum: P less than 0.001). After a minimum follow-up of 30 months, out of 40 patients with no local invasion and/or distant metastases, 100% (9/9) of those with DNA-diploid neoplasias showed no signs of disease relapse, vs. 55% (17/31) of the DNA-ane…
TP53 mutations and S-phase fraction but not DNA-ploidy are independent prognostic indicators in laryngeal squamous cell carcinoma
2005
ToprospectivelyevaluatetheprognosticsignificanceofTP53,H-,K-,andN-Rasmutations,DNA-ploidyandS-phasefraction(SPF) in patients affected by locally advanced laryngeal squamous cell carcinoma (LSCC). Eight-one patients (median follow-up was 71 months) who underwent resective surgery for primary operable locally advanced LSCC were analyzed. Tumor DNA was screened for mutational analysis by PCR/SSCP and sequencing. DNA-ploidy and SPF were performed byflow cytometric analyses. Thirty-six patients (44%) had, at least, a mutation in the TP53 gene. Of them, 22% (8/36) had double mutations and 3% (1/36) had triplemutations.Intotal,46TP53mutationswereobserved.Themajority(41%)oftheseoccurinexon5(19/46),…
Effects of tetraploidy on olive floral and fruit biology
2014
Floral biology and fruit development were studied in Leccino Compact (LC), a polyploid olive mutant of cultivar Leccino (L). This mutant, considered a mixoploid with both diploid and tetraploid cells, has thicker leaves and fruit size similar to the diploid cultivar. So far, no information is available on its floral biology. In this study, the ploidy level of the LC fruit epicarp, analyzed by flow cytometry, was determined to be tetraploid. Pollen size distribution confirmed that most flowers were tetraploid. Morphological and histological measurements of various floral structures and fruits were carried out on the two genotypes, and LC showed larger floral structures (i.e. rachis, flower a…
DNA aneuploidy and high proliferative activity but not K-ras-2 mutations as independent predictors of clinical outcome in operable gastric carcinoma:…
2001
BACKGROUND The prognostic value of DNA ploidy, S-phase fraction (SPF) and K-ras-2 mutations in gastric carcinoma (GC) has not yet been clearly defined. The aim of this study was to clarify the association between biomolecular variables, tumor characteristics, and clinical outcome in GC patients. METHODS Resected specimens from a consecutive series of 69 patients with GC who underwent potentially curative surgery were studied prospectively. DNA ploidy and SPF were assessed by flow cytometry on multiple frozen tumor samples, whereas K-ras-2 mutations were detected by polymerase chain reaction followed by single-strand conformation polymorphism. All the patients involved in this study were fol…
Prognosis in lower lip squamous cell carcinoma: assessment of tumor factors.
1998
We studied a consecutive series of 54 cases of lower lip squamous cell carcinoma (LLSCC) in order to identify any variables which might predict the development of lymph node metastases. The cases were divided into 38 tumors without metastases (group I) and 16 tumors with lymph node metastases (group II). The following factors were investigated: tumor size, histologic grading maximal thickness, perineural invasion, DNA ploidy and PCNA expression. In conclusion, we found that LLSCC greater than 2 cm in diameter, with histological grading G3-G4, thickness of more than 6 mm, DNA aneuploidy and high PCNA expression (PCNA LI > 0.48), were at high risk for the development of lymph node metastases.
DNA-Ploidy, Morphometric-Stereological and P-Glycoprotein Study of Superficial Bladder Carcinomas
1992
We carried out a DNA-ploidy, morphometric-stereologic and P-glycoprotein study on 40 newly diagnosed superficial bladder cancer patients (G1-G2), correlating the results with histological grade and clinical outcome. Variations in the number of patients who present recurrences, progression or remain tumor-free during the whole follow-up period (at least 5 years) were not significant when related to nuclear size, proliferative diploid index, presence of aneuploidy and expression of P-glycoprotein. It is striking how the majority of disease-free subjects showed a proliferative diploid index higher than 10%. Moreover, 3 of them presented an aneuploid cell population. In our study, only histolog…
Specific codon 13 K-ras mutations are predictive of clinical outcome in colorectal cancer patients, whereas codon 12 K-ras mutations are associated w…
2002
Background: K-ras mutations, one of the earliest events observed in colorectal carcinogenesis, are mostly found in codons 12 and 13, and less frequently in codon 61, all three of which are estimated to be critical for the biological activity of the protein. Nevertheless the prognostic significance of such mutations remains controversial. Our purpose was to assess whether any or specific K-ras mutations in primary colorectal cancer had prognostic significance and were linked to clinico-pathological parameters. Patients and methods: Paired tumor and normal tissue samples from a consecutive series of 160 untreated patients (median of follow up 71 months), undergoing resective surgery for prima…