4-Deoxyraputindole C induces cell death and cell cycle arrest in tumor cell lines

Several molecules extracted from natural products exhibit different biological activities, such as ion channel modulation, activation of signaling pathways, and anti-inflammatory or antitumor activity. In this study, we tested the antitumor ability of natural compounds extracted from the Raputia praetermissa plant. Among the compounds tested, an alkaloid, here called compound S4 (4-Deoxyraputindole C), showed antitumor effects against human tumor lineages. Compound S4 was the most active against Raji, a lymphoma lineage, promoting cell death with characteristics that including membrane permeabilization, dissipation of the mitochondrial potential, increased superoxide production, and lysosomal membrane permeabilization. The use of cell death inhibitors such as Z-VAD-FMK (caspase inhibitor), necrostatin-1 (receptor-interacting serine/threonine-protein kinase 1 inhibitor), E-64 (cysteine peptidases inhibitor), and N-acetyl- L -cysteine (antioxidant) did not decrease compound S4-dependent cell death. Additionally, we tested the effect of cellular activity on adherent human tumor cells. The highest reduction of cellular activity was observed in A549 cells, a lung carcinoma lineage. In this lineage, the effect on the reduction of the cellular activity was due to cell cycle arrest, without plasma membrane permeabilization, loss of the mitochondrial potential or lysosomal membrane permeabilization. Compound S4 was able to inhibit cathepsin B and L by a nonlinear competitive (negative co-operativity) and simple-linear competitive inhibitions, respectively. The potency of inhibition was higher against cathepsin L. Compound S4 promoted cell cycle arrest at G ₀ and G ₂ phase, and increase the expression of p16 and p21 proteins. In conclusion, compound S4 is an interesting molecule against cancer, promoting cell death in the human lymphoma lineage Raji and cell cycle arrest in the human lung carcinoma lineage A549.     

Effects of the neutral household detergent on the behaviour and personality of guppy Poecilia reticulata (Peters, 1859) (Osteichthyes: Poeciliidae)

acta ethologica - Chemical pollution of aquatic environments has been increasing in recent times, causing great damage to the ecosystems and to the fishery sector. Pollutants can negatively alter...     

Extraocular photoreception and circadian entrainment in nonmammalian vertebrates

In mammals both the regulation of circadian rhythms and photoperiodic responses depend exclusively upon photic information provided by the lateral eyes; however, nonmammalian vertebrates can also rely on multiple extraocular photoreceptors to perform the same tasks. Extraocular photoreceptors include deep brain photoreceptors located in several distinct brain sites and the pineal complex, involving intracranial (pineal and parapineal) and extracranial (frontal organ and parietal eye) components. This review updates the research field of the most recent acquisitions concerning the roles of extraocular photoreceptors on circadian physiology and behavior, particularly photic entrainment and sun compass orientation.     

Impact of the training program on lipid profile and cardiac health

The aim of this study was to investigate the effects of training programs on serum lipid profile and myocardial oxidative stress. Male Wistar rats (2 mo-old) were divided into three groups (n = 8): sedentary (S), loadless trained (T) and trained-overload 2% body weight (TL). T and TL were trained through swimming for 9 weeks. T and TL rats had increased myocardial lipoperoxide (TBA) and lipid hydroperoxide (HP), whereas HP was higher in TL than in T animals. Superoxide dismutase (SOD) activities were lowest in TL. Myocardial glutathione peroxidase (GSH-Px) was lower in TL than in T and S rats. TL decreased HDL-cholesterol and increased LDL-cholesterol. The serum lactate dehydrogenase and TBA were increased, while SOD and GSH-Px activities were decreased in TL rats. Loadless training was able to improve HDL-cholesterol and to reduce LDL-cholesterol. In conclusion, the loadless training program induced beneficial effects on lipid profile, while overload training induced dyslipidemic profile that was associated with serum oxidative stress. The overload training program was deleterious relative to loadless training program, increasing myocardial oxidative stress.     

Role of anti-cyclic citrullinated peptide antibodies in discriminating patients with rheumatoid arthritis from patients with chronic hepatitis C infection-associated polyarticular involvement

This study was performed to assess the utility of anti-cyclic citrullinated peptide (anti-CCP) antibodies in distinguishing between patients with rheumatoid arthritis (RA) and patients with polyarticular involvement associated with chronic hepatitis C virus (HCV) infection. Serum anti-CCP antibodies and rheumatoid factor (RF) were evaluated in 30 patients with RA, 8 patients with chronic HCV infection and associated articular involvement and 31 patients with chronic HCV infection without any joint involvement. In addition, we retrospectively analysed sera collected at the time of first visit in 10 patients originally presenting with symmetric polyarthritis and HCV and subsequently developing well-established RA. Anti-CCP antibodies and RF were detected by commercial second-generation anti-CCP2 enzyme-linked immunosorbent assay and immunonephelometry respectively. Anti-CCP antibodies were detected in 23 of 30 (76.6%) patients with RA but not in patients with chronic HCV infection irrespective of the presence of articular involvement. Conversely, RF was detected in 27 of 30 (90%) patients with RA, 3 of 8 (37.5%) patients with HCV-related arthropathy and 3 of 31 (9.7%) patients with HCV infection without joint involvement. Finally, anti-CCP antibodies were retrospectively detected in 6 of 10 (60%) patients with RA and HCV. This indicates that anti-CCP antibodies can be useful in discriminating patients with RA from patients with HCV-associated arthropathy.     

Development of an enzyme-linked immunosorbent assay for detection of IgM antibodies to Babesia bigemina in cattle

A crude antigenic preparation of Babesia bigemina was used to develop an ELISA for the detection of IgM antibodies. Optimal dilutions of the antigen, using positive and negative reference sera, were determined by checkerboard titrations. Negative sera from cattle imported from tick-free areas, serum samples collected from infected B. bigemina cattle were used to validate the test. The specificity was 94% and sensitivity of the Elisa 87.5%. Sera from 385 cattle deriving from areas free from tick-borne diseases, which were submitted to a preimmunization process, were screened by this technique. The Elisa detected seroconversion on the 14th day post-inoculation in animals either infested with Boophilus microplus ticks (infected with B. bigemina), or inoculated with B. bigemina infected blood. Antibody titers decreased after day 33; however, all animals remained positive until the end of the experiment (124 days). The ELISA described may prove to be an appropriate serological test for the detection of IgM antibodies against B. bigemina.     

The polytetrafluoroethylene-covered stent: a device with multiple potential advantages

The polytetrafluoroethylene (PTFE)-covered stent has emerged in the past year as a device with multiple potential advantages. Its structure (a sandwich composed of a layer of PTFE membrane between two stents) makes this the ideal tool for treating coronary ruptures, and for excluding coronary aneurysms. Furthermore, this device may be useful in the treatment of aortocoronary vein graft stenosis. In the present review, the authors summarize experiences with covered stents, and focus attention on available data on the implantation of PTFE-covered stents in human beings to treat coronary ruptures, aneurysms and aortocoronary vein graft stenosis.     

The synthetic peptide RPRAATF allows specific assay of Akt activity in cell lysates

The Akt protein kinase is a critical signaling molecule in a range of cellular processes. A key to identifying the role of this pleiotropic kinase in any particular process is the ability to quantitate its activity. In this study we show that the synthetic peptide RPRAATF is a specific substrate for the kinase in crude cell extracts, thus enabling rapid, convenient, and sensitive assay of Akt activity. Peptide kinase activity was confined to a single peak upon sequential ion-exchange chromatography of whole-cell extracts of Balb/c 3T3 fibroblasts. This activity was stimulated by both platelet-derived growth factor and pervanadate, phosphatidyl inositol 3-kinase dependent, and inhibited by specific immunodepletion with anti-Akt antisera. Furthermore, direct assays of crude extracts from a range of cell types using this peptide were consistent with the results obtained using specific immunoprecipitation assays.     

Reduction of 1,4-quinone and ubiquinones by hydrogen atom transfer under UVA irradiation

1,4-Benzoquinone, coenzyme Q 0 and Q 10 were reacted with a series of hydrogen donors in the ESR cavity in the presence or absence of UVA irradiation. The signals of the radicals generated from the hydrogen donors or of those of the semiquinones were detected. The reaction mechanism was interpreted by a hydrogen atom transfer instead of the usual electron transfer mechanism on the basis of the redox potentials of the reactants and the Marcus theory. The hydrogen atom transfer is explained by the excited triplet state of quinones, which, on the basis of quantum mechanic calculations, may be reached even under visible light. In some cases, hydrogen atom transfer was also observed without irradiation, although to a lesser extent.     

Direct identification of tyrosine 474 as a regulatory phosphorylation site for the Akt protein kinase

Understanding the regulation of Akt has been of major interest for elucidating the control of normal cellular physiology as well as malignant transformation. The paradigm for activation of Akt involves phosphatidylinositol 3-kinase-dependent membrane localization followed by activating phosphorylation of Thr-308 and Ser-473. Many of the activating signals for Akt involve the stimulation of receptor and non-receptor tyrosine kinases, and the most potent activator known is the tyrosine phosphatase inhibitor pervanadate, highlighting a possible role for tyrosine phosphorylation in the regulation of the enzyme. In this study we show that activation of Akt by pervanadate or serum is associated with tyrosine phosphorylation of Akt. In addition, in SKOV3 ovarian carcinoma cells that exhibit high basal levels of Akt activity, Akt was tyrosine-phosphorylated in the basal state, and this phosphorylation was further enhanced by both pervanadate and insulin-like growth factor-1. We have used NH(2)-terminal sequencing and phosphate release analysis to directly identify Tyr-474 as the site of tyrosine phosphorylation. Substitution of Tyr-474 with phenylalanine abolished tyrosine phosphorylation of Akt and resulted in up to 55% inhibition of Akt activation, indicating phosphorylation at Tyr-474 is required for full activation of the kinase. Our data identifies a novel regulatory mechanism for this pleiotropic enzyme that may be applicable to the AGC family of protein kinases given the conserved nature of the COOH-terminal hydrophobic motif containing Tyr-474.