Ruthenium polypyridyl complexes and their modes of interaction with DNA : is there a correlation between these interactions and the antitumor activity of the compounds?

Various interaction modes between a group of six ruthenium polypyridyl complexes and DNA have been studied using a number of spectroscopic techniques. Five mononuclear species were selected with formula [Ru(tpy) L1L2](2-n)?, and one closely related dinuclear cation of formula [{Ru(apy)(tpy)}2{l-H2N(CH2)6NH2}]4?. The ligand tpy is 2,20:60,200-terpyridine and the ligand L1 is a bidentate ligand, namely, apy (2,20-azobispyridine), 2-phenylazopyridine, or 2-phenylpyridinylmethylene amine. The ligand L2 is a labile monodentate ligand, being Cl-, H2O, or CH3CN. All six species containing a labile L2 were found to be able to coordinate to the DNA model base 9-ethylguanine by 1H NMR and mass spectrometry. The dinuclear cationic species, which has no positions available for coordination to a DNA base, was studied for comparison purposes. The interactions between a selection of four representative complexes and calf-thymus DNA were studied by circular and linear dichroism. To explore a possible relation between DNA-binding ability and toxicity, all compounds were screened for anticancer activity in a variety of cancer cell lines, showing in some cases an activity which is comparable to that of cisplatin. Comparison of the details of the compound structures, their DNA binding, and their toxicity allows the exploration of structure–activity relationships that might be used to guide optimization of the activity of agents of this class of compounds

A RADIOCARBON CHRONOLOGY FOR THE ACERAMIC SHELL-MIDDENS OF COASTAL OMAN

Our knowledge of the prehistory of coastal Oman has greatly increased during the last ten years. This article considers the radiocarbon chronology of the aceramic shell-middens scattered along the coast between Muscat, to the north, and Shuwayr, to the south. The appearance of these middens seems to correspond to the climatic deterioration that, according to more recent results, took pIace around the middle of the seventh millennium BP.The number of sites seems to have increased since the beginning of the actual arid phase, around 6000 B

Modern wolves trace their origin to a late Pleistocene expansion from Beringia

Grey wolves (Canis lupus) are one of the few large terrestrial carnivores that maintained a wide geographic distribution across the Northern Hemisphere throughout the Pleistocene and Holocene. Recent genetic studies have suggested that, despite this continuous presence, major demographic changes occurred in wolf populations between the late Pleistocene and early Holocene, and that extant wolves trace their ancestry to a single late Pleistocene population. Both the geographic origin of this ancestral population and how it became widespread remain a mystery. Here we analyzed a large dataset of novel modern and ancient mitochondrial wolf genomes, spanning the last 50,000 years, using a spatially and temporally explicit modeling framework to show that contemporary wolf populations across the globe trace their ancestry to an expansion from Beringia at the end of the Last Glacial Maximum - a process most likely driven by the significant ecological changes that occurred across the Northern Hemisphere during this period. This study provides direct ancient genetic evidence that long-range migration has played an important role in the population history of a large carnivore and provides an insight into how wolves survived the wave of megafaunal extinctions at the end of the last glaciation. Moreover, because late Pleistocene grey wolves were the likely source from which all modern dogs trace their origins, the demographic history described in this study has fundamental implications for understanding the geographical origin of the dog

Dead or alive?: investigating long-distance transport of live fallow deer and their body parts in antiquity

The extent to which breeding populations of fallow deer were established in Roman Europe has been obscured by the possibility that the skeletal remains of the species, in particular Dama foot bones and antlers, were traded over long distances as objects in their own right. This paper sets out to refine our understanding of the evidence for the transportation of living and dead fallow deer in Iron Age and Roman Europe. To achieve this, museum archives containing purportedly early examples of Dama antler were searched, with available specimens sampled for carbon, nitrogen and strontium isotope analyses, and compared with data for archaeological fallow deer from across Europe. Importantly, the resulting isotope values can be interpreted in light of new modern baseline data for fallow deer presented here. Together these multi-isotope results for modern and archaeological fallow deer provide a more critical perspective on the transportation of fallow deer and their body parts in antiquity

The local marine reservoir effect at Kalba (UAE) between the Neolithic and Bronze Age: An indicator of sea level and climate changes

We investigate the local marine reservoir effect at Kalba, United Arab Emirates (UAE), between the Neolithic and Bronze Age with respect to possible changes through time and mollusk species diversity. Two distinctive species living in close proximity to the mangrove of Khor Kalba provide insights into ocean circulation patterns in this coastal environment. The species selected are the bivalve Anadara uropigimelana, and the gastropod Terebralia palustris. They have been an important local food resource for humans since at least the Neolithic. Our results show that for the Neolithic and Bronze Age, the reservoir effects DR are quite different for the species selected. For Anadara spp. the DR decreases from 576 ± 90 to 112 ± 44 years, while for Terebralia spp. the reduction ranges from 389 ± 66 to 19 ± 36 years. These results are coeval with other multi-proxies (stalagmite records and sea level changes) for the middle Holocene, and suggest that the main cause of the decreasing reservoir effect is a changing e in this case declining - sea level and an increasingly drier climate