Quantity-quality trade-off in the acquisition of token preference by capuchin monkeys (Sapajus spp.).

Money represents a cornerstone of human modern economies and how money emerged as a medium of exchange is a crucial question for social sciences. Although non-human primates have not developed monetary systems, they can estimate, combine and exchange tokens. Here, we evaluated quantity-quality trade-offs in token choices in tufted capuchin monkeys as a first step in the investigation of the generalizability of tokens as reinforcers, which is a potentially relevant factor underlying the emergence of money in humans. We measured capuchins' exchange preferences when they were repeatedly provided with 10 units of three token types yielding food combinations varying in quantity and quality. Overall, capuchins maximized their quantitative payoff, preferring tokens associated with a higher food amount, rather than showing violations of rationality. However, some individuals did not maximize their qualitative payoff, possibly because of conditional valuation effects or owing to the choice overload phenomenon, according to which too many options reduce the accuracy of choice. Our study supports the importance of comparative research to finely analyse the multiple components shaping the economic behaviours of other species, possibly to achieve a more comprehensive, evolutionary- and ecologically based understanding of human economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

Met signaling regulates growth, repopulating potential and basal cell-fate commitment of mammary luminal progenitors: implications for basal-like breast cancer.

Basal-like breast cancer is an aggressive subtype of mammary carcinoma. Despite expressing basal markers, typical of mammary stem cells, this tumor has been proposed to originate from luminal progenitors, which are downstream of stem cells along the mammary epithelial hierarchy. This suggests that committed luminal progenitors may reacquire basal, stem-like characteristics, but the mechanisms that regulate this transition remain unclear. Using mouse models, we found that luminal progenitors express high levels of the Met receptor for hepatocyte growth factor (HGF), as compared with the other mammary epithelial sub-populations. Constitutive activation of Met led luminal progenitors to attain stem cell properties, including enhanced clonogenic activity in vitro and de novo ability to reconstitute mammary glands in repopulation assays in vivo. Moreover, in response to Met signaling, luminal progenitors gave rise to hyperplastic ductal morphogenesis and preferentially underwent basal lineage commitment at the expense of luminal cell-fate specification. Opposite and symmetric results were produced by systemic pharmacological inhibition of Met. Hence, Met signaling targets luminal progenitors for expansion, impairs their differentiation toward the mature luminal phenotype and enables their commitment toward the basal lineage. These results emphasize a critical role for Met in promoting deregulated proliferation and basal plasticity of normal luminal progenitors in the mammary gland, a complex of events that may be required for sustaining the functional and phenotypic properties of basal-like breast tumors.

Alkylphenol oxidation with a laccase from a white-rot fungus: effects of culture induction and of ABTS used as a mediator.

We investigated the potential of the laccase from the white-rot fungus Marasmius quercophilus to transform certain alkylphenols (p-nonylphenol, p-octylphenol and p-t-octylphenol). We tested the reactivity of this enzyme under different conditions: in liquid cultures and using the partially purified laccase with and without 2,2'-azino-bis-3-ehtylbenzothiazoline-6-sulfonicacid (ABTS) as a mediator. The percentage of p-t-octylphenol disappearance in liquid cultures was 69.0 ± 1.5% and 81 ± 5% after a 8-d or 15-d incubation, respectively, with p-nonylphenol, these percentages were 62 ± 4% and 91 ± 6% and with p-octylphenol 37 ± 3% and 65 ± 1% after a 15-d and a 21-d incubations, respectively. Induced pre-cultures were also used to inoculate the liquid cultures to enhance p-octylphenol transformation: the percentages of disappearance were 91.0 ± 0.5% and 97 ± 1% after a 8-d and a 15-d incubation, respectively. Mass spectrometry analysis showed that the products of oxidation of p-octylphenol were dimers with a mass of 411 m/z. Furthermore, we identified a purple compound (m/z 476) formed when ABTS was added to the reaction medium with the purified laccase. This result confirms that, in complex environments such as soils or litters where many molecules can interact with the enzyme substrate or the product of oxidation, laccase activities and those of other phenoloxidases should not be measured with ABTS.

[Evaluation of various hemorheological parameters in nonagenarians: evidence of an increase of fibrinogen]. / Valutazione di alcuni parametri emoreologici in soggetti ultranovantenni: evidenza di un aumento del fibrinogeno.

Cardiovascular disease is the most frequent cause of mortality in the elderly. A reduced microvascular blood flow associated with an increase in atherosclerosis might contribute to age related increases in the incidence of ischemic vascular disease. In order to evaluate the effect of age on some haemorheological parameters, blood and plasma viscosity and fibrinogen have been measured in 10 healthy elderly subjects, aged between 88 and 96 years, compared with 15 healthy young subjects (mean age 37 years). Elderly subjects showed a significant increase in plasma fibrinogen (p less than 0.0005) and a trend to an increase in plasma viscosity, whereas no difference was present in blood viscosity. These data confirm that aging is associated with a greater deal of thrombotic risk factors, the most important of which seems to be fibrinogen.

Bis-substituted hydroxy-anthracenediones: DNA binding and biological activity.

Three new hydroxy-9,10-anthracenedione derivatives (compounds 1-3 in Figure 1), bearing two charged or polar side chains at positions 2 and 4/5 of the tricyclic system, have been investigated for their DNA binding, cytotoxic and genotoxic activity. The interaction mode with nucleic acids is intercalative for compounds 1 and 2, while external and intercalative binding probably coexist for compound 3. Complexation of the nucleic acid occurs in all cases in a cooperative manner, so that drug binding favours further binding to double helical DNA. The scale of the intrinsic binding constant is discussed in terms of the nature and position of the side chain. Cell growth and DNA synthesis inhibition data match quite well with DNA affinity. Alkaline elution experiments show a correlation between drug cytotoxicity and DNA damage. Our results indicate that the position and number of OH groups, as well as of charged side chains, play an important role in modulating drug affinity for DNA and the consequent biological effects.

Genotoxic activity of some water-soluble derivatives of 5-methoxypsoralen and 8-methoxypsoralen.

This paper shows some results obtained by assaying the genotoxic activity on procaryotic and eucaryotic cells of some water-soluble psoralen derivatives. In particular, six newly synthesized derivatives of 5-methoxypsoralen (5-MOP) and of 8-methoxypsoralen (8-MOP) were tested; in previous studies they showed a strong anti-proliferative activity and a slight phototoxic effect; moreover, in view of a clinical use in the therapy of hyperproliferative skin diseases, these drugs should be less toxic than their parent compounds because of their good water solubility which could lead to a more efficient absorption and excretion. All the compounds tested here have shown genotoxic activity on both procaryotic and eucaryotic systems: however, on the procaryotic cells the water-soluble derivatives were less genotoxic than their respective parent compounds 5-MOP and 8-MOP. Quite different results were obtained on V79 Chinese hamster cells, showing that, in general, the 8-methoxy-derivatives are more mutagenic than the methoxy-ones, although the 5-MOP itself was shown to be highly genotoxic in this system. This fact confirms that a conclusive estimate of the genotoxic risk related to the use of new drugs cannot be drawn from the results obtained on a single biological system.

Biological properties of benzodifuran derivatives.

The antiviral activity and the effect on DNA synthesis of two benzodifuran compounds were studied. DNA and some RNA viruses were significantly inhibited by concentrations ranging from 15 to 30 nM/ml. The inhibition of DNA synthesis in host cells was obtained with concentrations higher than those inhibiting virus replication. A favourable ratio between antiviral activity and inhibition of DNA synthesis of the host cells is present in these compounds. This activity is substantially due to the ability of the compounds to complex with DNA.

New anthracenedione derivatives: interaction with DNA and biological effects.

Two anthracenedione derivatives [1 - (omega - diethylaminopropylamido) - 4 - hydroxy - 9,10 - anthracenedione hydrochloride (I) and 1 - (omega - diethylaminopropylamido) - 2 - methoxy - 4 - hydroxy - 9, 10 - anthracenedione hydrochloride (II)], having an electron-rich planar chromophore and an amino-substituted side chain, have been synthesized. Their binding ability to DNA was investigated by means of spectroscopic, equilibrium dialysis and fluorescence measurements. Their inhibition efficiency on nucleic acid synthesis was also evaluated both in mouse and human cells. Our results indicate that, in comparison with adriamycin, compound I shows a slightly weaker complexation ability to DNA, while compound II interacts with DNA at a substantially lower level. These data match quite well with the biological response on the inhibition of DNA and RNA synthesis exhibited by the above mentioned compounds; in fact compound I is slightly less efficient than adriamycin and about ten times more efficient than compound II. The close relationship between the results of physicochemical and biological studies is discussed.