RESUMO
Argyranthemum frutescens (L.) Sch.Bip. and Rhodanthemum gayanum (Coss. & Durieu) B. H. Wilcox, K. Bremer & Humphries are capable of hybridization. To expand flower color variation in this intergeneric hybrid group, we performed crosses using A. frutescens as the seed parent and R. hosmariense (Ball) B. H. Wilcox, K. Bremer & Humphries, R. catananche (Ball) B. H. Wilcox, K. Bremer & Humphries as the pollen parent. One plantlet was obtained from each cross between the white to pale pink-flowered A. frutescens and white-flowered R. hosmariense, and from a cross between the pink-flowered A. frutescens and cream to pale yellow-flowered R. catananche, via ovule culture. The cross with R. hosmariense produced an individual with white to pale pink ray florets, and the cross with R. catananche produced an individual with red ray florets. The flower and leaf shape of the progenies was intermediate between the parents, and other morphological traits were also characterized in the same manner. Morphological observations and a cleaved amplified polymorphic sequence marker-based determination, using the internal transcribed spacer region as a target for amplification and the restriction enzyme Afl II, revealed that both individuals are hybrids between A. frutescens and R. hosmariense, R. catananche. To the best of our knowledge, this is the first study to report that crossbreeding between A. frutescens (seed parent) and R. hosmariense, R. catananche (pollen parent) is possible. Moreover, further development of Argyranthemum breeding, especially that of a series of hybrid cultivars with different flower colors, is expected.
RESUMO
To introduce useful characteristics such as fragrance into Argyranthemum frutescens (L.) and to expand the variation, we conducted crosses using A. frutescens as the seed parent and Chamaemelum nobile (L.) All. as the pollen parent. All the tested cross combinations between the three strains of A. frutescens and one strain of C. nobile produced embryos, and healthy plants were obtained by ovule culture. The obtained plantlets had a white ray floret, and the leaf shape was intermediate to those of the parents. The individuals obtained from this cross were subjected to two methods to determine hybridity: flow cytometry analyses and cleaved amplified polymorphic sequence (CAPS) markers. For the CAPS marker, we selected the internal transcribed spacer (ITS) region, which is highly variable among the genera, as the region to be amplified. We selected restriction enzymes BmgT120 I and Afl II, which selectively cut common sequences in the genus Argyranthemum, based on the sequence analysis of one parent strain each of A. frutescens and C. nobile and alignment with known sequences of related species. Flow cytometry analyses and CAPS markers revealed that the individuals obtained from the cross between A. frutescens and C. nobile are intergeneric hybrids. In addition, these established methods were capable of quickly and reliably identifying hybrids between A. frutescens and C. nobile. This report shows for the first time that crossbreeding between A. frutescens (seed parent) and C. nobile (pollen parent) is possible, and further development of Argyranthemum breeding, such as the expansion of variation by intergeneric crosses, is expected.
RESUMO
The T and B cell repertoire make up the adaptive immune system and is mainly generated through somatic V(D)J gene recombination. Thus, the VJ gene usage may be a potential prognostic or predictive biomarker. However, analysis of the adaptive immune system is challenging due to the heterogeneity of the clonotypes that make up the repertoire. To address the heterogeneity of the T and B cell repertoire, we proposed a novel ensemble feature selection approach and customized statistical learning algorithm focusing on the VJ gene usage. We applied the proposed approach to T cell receptor sequences from recovered COVID-19 patients and healthy donors, as well as a group of lung cancer patients who received immunotherapy. Our approach identified distinct VJ genes used in the COVID-19 recovered patients comparing to the healthy donors and the VJ genes associated with the clinical response in the lung cancer patients. Simulation studies show that the ensemble feature selection approach outperformed other state-of-the-art feature selection methods based on both efficiency and accuracy. It consistently yielded higher stability and sensitivity with lower false discovery rates. When integrated with different classification methods, the ensemble feature selection approach had the best prediction accuracy. In conclusion, the proposed novel approach and the integration procedure is an effective feature selection technique to aid in correctly classifying different subtypes to better understand the signatures in the adaptive immune response associated with disease or the treatment in order to improve treatment strategies.
RESUMO
In order to study telomerase activation in normal cells, a telomerase-immortalized fibroblast cell line, hTERT-BJ1, treated with a telomerase inhibitor, 3'-azido-2',3'-dideoxyguanosine (AZddG), is considered to be a good model. Long-term treatment with AZddG resulted in telomere shortening from 10-20 kbp to 5-6 kbp in cultured hTERT BJ1 cells. However, the telomere length then stabilized. As expected, removal of AZddG from the culture medium induced telomere lengthening in the cells, suggesting that telomerase activity was recovered upon AZddG removal. The effect of recovery of telomerase activity in hTERT-BJ1 cells will be investigated in future studies.
