Selective cytotoxicity of withaphysalins in myeloid leukemia cell lines versus peripheral blood mononuclear cells

Withaphysalins are C(28)-steroidal lactones structurally based on the ergostane skeleton that possess antiproliferative activity against tumor cell lines. In the present study, the antileukemic actvity of withaphysalin O (1), M (2), and N (3) isolated from Acnistus arborescens, against two leukemic cell lines, HL-60 and K562, was evaluated, and the cytotoxicity compared with the effects on peripheral blood mononuclear cells (PBMC). All tested compounds reduced the number of viable cells of the tumor cell lines after 24 h of exposure, except for compound 2 against the K562 cell line. The reduction was time-and concentration-dependent, and the IC(50) values ranged from 0.7 to 3.5 microM after 72 h of incubation. In addition to the growth inhibitory properties, the drugs decreased DNA synthesis after 24 h of drug exposure evaluated by the 5-bromo-2 -deoxyuridine incorporation method. None of the tested compounds reduced the number of PBMC (IC(50)>20 microM) after 72 h of incubation, in contrast to doxorubicin that decreased viable cells and increased non-viable cells even after 24 h of incubation. Morphological analysis of treated cells using hematoxylin/eosin staining indicated the presence of necrotic cells for all tested compounds in HL-60, confirmed by the use of acridine orange/ethidium bromide staining. In addition to necrotic cells, K562 cells showed morphological alterations consistent with apoptosis.     

Studies on the cytotoxicity of miscellaneous compounds from Eupatorium betonicaeforme (D.C.) Baker (Asteraceae)

A detailed study on the cytotoxic effects of five known constituents isolated from the flowers and roots of Eupatorium betonicaeforme is reported, including 2,2-dimethyl-6-vinylchroman-4-one (1), 2-senecioyl-4-vinylphenol (2), 6-acetyl-2,2-dimethylchroman-4-one (3), (4E)-8beta-angeloyloxy-9beta,10beta-dihydroxy-1-oxogermacra-4,11(13)-dien-12,6alpha-olide (4), and 3beta-hydroxyicosan-1,5beta-olide (5). The sesquiterpene lactone 4 exhibited the highest cytotoxicity, with IC50 values ranging from 3.9 to 9.9 microM, showing some degree of cell selectivity. The antiproliferative activity of 4 was examined towards HL-60 cells, and found to diminish cell viability in a dose-dependent manner. Moreover, at all concentrations tested, there was a decrease in the number of cells capable of incorporating 5-bromo-2'-deoxyuridine (BrdU), indicating disruption of DNA synthesis. The morphological changes induced by 4 were compatible with apoptotic cell death. This work, thus, corroborates the anticancer potential of Eupatorium secondary metabolites.     

Creatine and creatinine quantification in olympic athletes: dried blood spot analysis pilot study

Capillary dried blood spot (DBS) samples facilitate field-based collection without venipuncture. This pilot study aims to evaluate the viability of creatine (Cr) and creatinine (Crt) quantification using fresh capillary serum (Cr_S/Crt_S) and DBS samples (Cr_DBS/Crt_DBS), using Flow Injection Analysis Mass Spectrometry (FIA – MS). Nine Olympic Athletes provided a capillary blood sample to assess Cr_S/Crt_S and Cr_DBS/Crt_DBS quantified by FIA – MS. No difference between Crt_S (mean ± SD: 813.6 ± 102.4 μmol/L) and Crt_DBS (812.4 ± 108.1 μmol/L) was observed with acceptable variance [SEM 88.7; CV 10.7%; ICC 0.57 (CI 95% 0.06 – 0.84)] and agreement [very strong (Spearman: r = 0.77; p < 0.01) or strong (Pearson: r = 0.56; p = 0.04); Bland Altman: lower (-193) and upper (+196) limits of agreement]. Cr_S (mean ± SD: 691.8 ± 165.2 μmol/L) was significantly different to Cr_DBS (2911 ± 571.4 μmol/L) with unacceptable variance [SEM 171.6; CV 27%; ICC 0.002 (CI 95% -0.02 – 0.07)] and ‘weak’ agreement [Spearman: r = 0.21, p = 0.47 and Pearson: r = 0.06, p = 0.84; Bland Altman lower (-3367) and upper (-1072) limits of agreement]. Crt quantification is viable using both Crt_S and Crt_DBS (but not for Cr and Cr_S/Cr_DBS), with the DBS tissue handling technique offering several methodological and practice facing advantages. Future work should expand upon the sample size, explore sport/discipline relevant analytes across a full competitive season, including key training, recovery and performance blocks of their periodized performance plan.     

Postglacial colonization of Europe by the barbastelle bat: agreement between molecular data and past predictive modelling

The barbastelle (Barbastella barbastellus) is a rare forest bat with a wide distribution in Europe. Here, we combine results from the analysis of two mtDNA fragments with species distribution modelling to determine glacial refugia and postglacial colonization routes. We also investigated whether niche conservatism occurs in this species. Glacial refugia were identified in the three southern European peninsulas: Iberia, Italy and the Balkans. These latter two refugia played a major role in the postglacial colonization process, with their populations expanding to England and central Europe, respectively. Palaeo‐distribution models predicted that suitable climatic conditions existed in the inferred refugia during the last glacial maximum (LGM). Nevertheless, the overlap between the current and the LGM distributions was almost inexistent in Italy and in the Balkans, meaning that B. barbastellus populations were forced to shift range between glacial and interglacial periods, a process that probably caused some local extinctions. In contrast, Iberian populations showed a ‘refugia within refugium’ pattern, with two unconnected areas containing stable populations (populations that subsisted during both glacial and interglacial phases). Moreover, the match between LGM models and the refugial areas determined by molecular analysis supported the hypothesis of niche conservatism in B. barbastellus. We argue that geographic patterns of genetic structuring, altogether with the modelling results, indicate the existence of four management units for conservation: Morocco, Iberia, Italy and UK, and Balkans and central Europe. In addition, all countries sampled possessed unique gene pools, thus stressing the need for the conservation of local populations.     

Steering directed protein evolution: strategies to manage combinatorial complexity of mutant libraries

How to explore protein sequence space efficiently and how to generate high-quality mutant libraries that allow to identify improved variants with current screening technologies are key questions for any directed protein evolution experiment. High-quality mutant libraries can be generated through improved random mutagenesis methodologies and by restricting diversity generation through computational methods to residues which have high success probabilities. Advances in mutant library design and computational tools to focus diversity generation are summarized in this minireview and discussed from an experimentalist point of view in the context of directed protein evolution.     

Nonlinear Optical Properties of Tungsten Lead–Pyrophosphate Glasses Containing Metallic Copper Nanoparticles

We have prepared heavy metal oxide glasses containing metallic copper nanoparticles with promising nonlinear optical properties which were determined by Z-scan and pump-probe measurements using femtosecond laser pulses. For the wavelengths within the plasmon band, we have observed saturable absorption and response times of 2.3 ps. For the other regions of the spectrum, reverse saturable absorption and lifetimes shorter than 200 fs were verified. The nonlinear refractive index is about 2.0?×?10^?19 m²/W from visible to telecom region, thus presenting an enhancement effect at wavelengths near the plasmon and Cu⁺² d–d band.     

Estimated comparative integration hotspots identify different behaviors of retroviral gene transfer vectors

Integration of retroviral vectors in the human genome follows non random patterns that favor insertional deregulation of gene expression and may cause risks of insertional mutagenesis when used in clinical gene therapy. Understanding how viral vectors integrate into the human genome is a key issue in predicting these risks. We provide a new statistical method to compare retroviral integration patterns. We identified the positions where vectors derived from the Human Immunodeficiency Virus (HIV) and the Moloney Murine Leukemia Virus (MLV) show different integration behaviors in human hematopoietic progenitor cells. Non-parametric density estimation was used to identify candidate comparative hotspots, which were then tested and ranked. We found 100 significative comparative hotspots, distributed throughout the chromosomes. HIV hotspots were wider and contained more genes than MLV ones. A Gene Ontology analysis of HIV targets showed enrichment of genes involved in antigen processing and presentation, reflecting the high HIV integration frequency observed at the MHC locus on chromosome 6. Four histone modifications/variants had a different mean density in comparative hotspots (H2AZ, H3K4me1, H3K4me3, H3K9me1), while gene expression within the comparative hotspots did not differ from background. These findings suggest the existence of epigenetic or nuclear three-dimensional topology contexts guiding retroviral integration to specific chromosome areas.     

Performance prediction of deep learning applications training in GPU as a service systems

Cluster Computing - Data analysts predict that the GPU as a service (GPUaaS) market will grow to support 3D models, animated video processing, gaming, and deep learning model training. The main...     

Modulation of auxin signalling through DIAGETROPICA and ENTIRE differentially affects tomato plant growth via changes in photosynthetic and mitochondrial metabolism

Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher V_cmax and J_max coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes.