Diallel cross among fresh market tomato inbreeding lines

The general combining ability (GCA), specific combining ability (SCA), and heterosis were studied in a complete diallel cross among fresh market tomato breeding lines with reciprocal excluded. Fifteen genotypes (five parents and ten hybrids) were tested using a randomized complete block design, with three replications, and the experiments were conducted in Itatiba, São Paulo state, Brazil, in 2005/06. The yield components evaluated were fruit yield per plant (FP), fruit number per plant (FN), average fruit weight (FW); cluster number per plant (CN); fruit number per cluster (FC), fruit wall thickness (FT) and number of locules per fruit (NL). Fruit quality components evaluated were total soluble solids (SS); total titratable acidity (TA); SS/TA ratio, fruit length (FL); fruit width (WI); length to width ratio (FL/WI). The data for each trait was first subjected to analysis of variance. Griffing's method 2, model 1 was employed to estimate the general (GCA) and specific (SCA) combining abilities. Parental and hybrid data for each trait were used to estimate of mid-parent heterosis. For plant fruit yield, IAC-2 was the best parental line with the highest GCA followed by IAC-4 and IAC-1 lines. The hybrids IAC-1 x IAC-2, IAC-1 x IAC-4 and IAC-2 x IAC-4 showed the highest effects of SCA. High heterotic responses were found for fruit yield and plant fruit number with values up to 49.72% and 47.19%, respectively. The best hybrids for fruit yield and plant fruit number were IAC-1 x IAC-2, IAC-1 x IAC-4 and IAC-2 x IAC-5, for fruit yield and plant fruit number, the main yield components.

Antiproliferative activity of Eremanthus crotonoides extracts and centratherin demonstrated in brain tumor cell lines

The genus Eremanthus is recognized by the predominance of sesquiterpene lactones from the furanoheliangolide type, a class of substances extensively tested against cancer cell lines. Thus, the species E. crotonoides (DC.) Sch. Bip., Asteraceae, obtained on "restinga" vegetation was evaluated against U251 and U87-MG glioma cell lines using the MTT colorimetric assay. Dichloromethane fraction was cytotoxic to both glioblastoma multiforme cell lines. We then conducted UPLC-PDA-ESI-MS/MS analysis of the dichloromethane fraction, which allowed the identification of the sesquiterpene lactones centratherin and goyazensolide. The isolation of centratherin was performed using chromatographic techniques and the identification of this substance was confirmed according to NMR data. Cytotoxic activity of centratherin alone was also evaluated against both U251 and U87-MG cells, which showed IC50 values comparable with those obtained for the commercial anticancer drug doxorubicin. All the tested samples showed cytotoxic activity against glioblastoma multiforme cells which suggests that E. crotonoides extracts may be important sources of antiproliferative substances and that the centratherin may serve as prototype for developing new antiglioblastoma drugs.

Rapid screening of potential autophagic inductor agents using mammalian cell lines

Recent progress in understanding the molecular basis of autophagy has demonstrated its importance in several areas of human health. Affordable screening techniques with higher sensitivity and specificity to identify autophagy are, however, needed to move the field forward. In fact, only laborious and/or expensive methodologies such as electron microscopy, dye-staining of autophagic vesicles, and LC3-II immunoblotting or immunoassaying are available for autophagy identification. Aiming to fulfill this technical gap, we describe here the association of three widely used assays to determine cell viability - Crystal Violet staining (CVS), 3-[4, 5-dimethylthiaolyl]-2, 5-diphenyl-tetrazolium bromide (MTT) reduction, and neutral red uptake (NRU) - to predict autophagic cell death in vitro. The conceptual framework of the method is the superior uptake of NR in cells engaging in autophagy. NRU was then weighted by the average of MTT reduction and CVS allowing the calculation of autophagic arbitrary units (AAU), a numeric variable that correlated specifically with the autophagic cell death. The proposed strategy is very useful for drug discovery, allowing the investigation of potential autophagic inductor agents through a rapid screening using mammalian cell lines B16-F10, HaCaT, HeLa, MES-SA, and MES-SA/Dx5 in a unique single microplate.

Structural stability of flexible lines in catenary configuration under torsion

Catenary risers can present during installation a very low tension close to seabed, which combined with torsion moment can lead to a structural instability, resulting in a loop. This is undesirable once it is possible that the loop turns into a kink, creating damage. This work presents a numerical methodology to analyze the conditions of loop formation in catenary risers. Stability criteria were applied to finite element models, including geometric nonlinearities and contact constraint due to riser-seabed interaction. The classical Greenhill's formula was used to predict the phenomenon and parametric analysis shows a “universal plot” able to predict instability in catenaries using a simple equation that can be applied for typical risers installation conditions and, generically, for catenary lines under torsion.