Effects of metal ion binding on structural dynamics of human hemopexin

Hemopexin (Hx) functions as a major heme scavenging protein in blood plasma and as such circulates without heme bound. In recent work, we have demonstrated that Hx binds metal ions in vitro in a manner that varies from one metal ion to another and that changes with heme binding. The structural consequences of metal ion binding to the form of Hx that dominates in plasma have now been evaluated by monitoring metal ion-linked changes in tertiary structure of the protein as reflected by changes in the near-UV CD spectrum and the ultraviolet absorption spectrum as a function of temperature. As part of this analysis we have developed thermally induced difference absorption maps (TIDAMs) to afford efficient visualization of temperature-dependent changes in the UV spectrum of Hx that are induced by binding of metal ions. The results are interpreted in terms of recent models proposed for metal ion binding sites on Hx and have implications for the possible modulation of heme binding to Hx by metal ions in vivo.     

Zooarchaeology and taphonomy of Aurora Stratum (Gran Dolina, Sierra de Atapuerca, Spain).

In 1994 and 1995, a 7 m(2)area was excavated at Level 6 of the Gran Dolina site, Atapuerca. A 25 cm deep sub-level, named Aurora Stratum, contained a large number of human fossils, stone tools and faunal remains. The appearance of human remains as part of a butchered faunal assemblage in association with stone tools raises an interesting question relating to human behaviour. The main aim of this paper, therefore, is to evaluate the nature and function of the human occupation at this cave site with a view to understanding the purposes of cannibalism. The zooarchaeological and taphonomic analyses of the macrovertebrate remains focus on species composition, weight and anatomic groups, as well as breakage intensity, type of fragmentation, and surface damage (particularly tool-induced damage) in order to evaluate the faunal source, butchering techniques and economic strategies of the human groups involved. We also studied the distribution and fossil refitting at the site to establish depositional and postdepositional disturbance. Diagenetic breakage due to sediment compression plays an important role in the assemblage, but the most extensive modifications are those produced by human activity for nutritional purposes.     

Formation of alkenes via degradation of tert-alkyl ethers and alcohols by Aquincola tertiaricarbonis L108 and Methylibium spp

Bacterial degradation pathways of fuel oxygenates such as methyl tert-butyl and tert-amyl methyl ether (MTBE and TAME, respectively) have already been studied in some detail. However, many of the involved enzymes are still unknown, and possible side reactions have not yet been considered. In Aquincola tertiaricarbonis L108, Methylibium petroleiphilum PM1, and Methylibium sp. strain R8, we have now detected volatile hydrocarbons as by-products of the degradation of the tert-alkyl ether metabolites tert-butyl and tert-amyl alcohol (TBA and TAA, respectively). The alkene isobutene was formed only during TBA catabolism, while the beta and gamma isomers of isoamylene were produced only during TAA conversion. Both tert-alkyl alcohol degradation and alkene production were strictly oxygen dependent. However, the relative contribution of the dehydration reaction to total alcohol conversion increased with decreasing oxygen concentrations. In resting-cell experiments where the headspace oxygen content was adjusted to less than 2%, more than 50% of the TAA was converted to isoamylene. Isobutene formation from TBA was about 20-fold lower, reaching up to 4% alcohol turnover at low oxygen concentrations. It is likely that the putative tert-alkyl alcohol monooxygenase MdpJ, belonging to the Rieske nonheme mononuclear iron enzymes and found in all three strains tested, or an associated enzymatic step catalyzed the unusual elimination reaction. This was also supported by the detection of mdpJK genes in MTBE-degrading and isobutene-emitting enrichment cultures obtained from two treatment ponds operating at Leuna, Germany. The possible use of alkene formation as an easy-to-measure indicator of aerobic fuel oxygenate biodegradation in contaminated aquifers is discussed.     

Migration patterns and navigation cues of Atlantic salmon post-smolts migrating from 12 rivers through the coastal zones around the Irish Sea

The freshwater phase of the first seaward migration of juvenile Atlantic salmon (Salmo salar) is relatively well understood when compared with our understanding of the marine phase of their migration. In 2021, 1008 wild and 60 ranched Atlantic salmon smolts were tagged with acoustic transmitters in 12 rivers in England, Scotland, Northern Ireland and Ireland. Large marine receiver arrays were deployed in the Irish Sea at two locations: at the transition of the Irish Sea into the North Atlantic between Ireland and Scotland, and between southern Scotland and Northern Ireland, to examine the early phase of the marine migration of Atlantic salmon smolts. After leaving their natal rivers' post-smolt migration through the Irish Sea was rapid with minimum speeds ranging from 14.03 to 38.56 km.day⁻¹ for Atlantic salmon smolts that entered the Irish Sea directly from their natal river, to 9.69–39.94 km.day⁻¹ for Atlantic salmon smolts that entered the Irish Sea directly from their natal estuary. Population minimum migration success through the study area was strongly correlated with the distance of travel, populations further away from the point of entry to the open North Atlantic exhibited lower migration success. Post-smolts from different populations experienced different water temperatures on entering the North Atlantic. This was largely driven by the timing of their migration and may have significant consequences for feeding and ultimately survivorship. The influence of water currents on post-smolt movement was investigated using data from previously constructed numerical hydrodynamic models. Modeled water current data in the northern Irish Sea showed that post-smolts had a strong preference for migrating when the current direction was at around 283° (west-north-west) but did not migrate when exposed to strong currents in other directions. This is the most favorable direction for onward passage from the Irish Sea to the continental shelf edge current, a known accumulation point for migrating post-smolts. These results strongly indicate that post-smolts migrating through the coastal marine environment are: (1) not simply migrating by current following (2) engage in active directional swimming (3) have an intrinsic sense of their migration direction and (4) can use cues other than water current direction to orientate during this part of their migration.     

The “Bear” Essentials: Actualistic Research on Ursus arctos arctos in the Spanish Pyrenees and Its Implications for Paleontology and Archaeology

Neotaphonomic studies of large carnivores are used to create models in order to explain the formation of terrestrial vertebrate fossil faunas. The research reported here adds to the growing body of knowledge on the taphonomic consequences of large carnivore behavior in temperate habitats and has important implications for paleontology and archaeology. Using photo- and videotrap data, we were able to describe the consumption of 17 ungulate carcasses by wild brown bears (Ursus arctos arctos) ranging the Spanish Pyrenees. Further, we analyzed the taphonomic impact of these feeding bouts on the bones recovered from those carcasses. The general sequence of consumption that we charted starts with separation of a carcass’s trunk; viscera are generally eaten first, followed by musculature of the humerus and femur. Long limb bones are not broken open for marrow extraction. Bears did not transport carcasses or carcass parts from points of feeding and did not disperse bones appreciably (if at all) from their anatomical positions. The general pattern of damage that resulted from bear feeding includes fracturing, peeling, crenulation, tooth pitting and scoring of axial and girdle elements and furrowing of the upper long limb bones. As predicted from observational data, the taphonomic consequences of bear feeding resemble those of other non-durophagus carnivores, such as felids, and are distinct from those of durophagus carnivores, such as hyenids. Our results have paleontological and archaeological relevance. Specifically, they may prove useful in building analogical models for interpreting the formation of fossil faunas for which bears are suspected bone accumulators and/or modifiers. More generally, our comparative statistical analyses draw precise quantitative distinctions between bone damage patterns imparted respectively by durophagus (modelled here primarily by spotted hyenas [Crocuta crocuta] and wolves [Canis lupus]) and non-durophagus (modelled here by brown bears and lions [Panthera leo]) carnivorans.     

Brain proteomics identifies potential simvastatin targets in acute phase of stroke in a rat embolic model

Finding an efficient neuroprotectant is of urgent need in the field of stroke research. The goal of this study was to test the effect of acute simvastatin administration after stroke in a rat embolic model and to explore its mechanism of action through brain proteomics. To that end, male Wistar rats were subjected to a Middle Cerebral Arteria Occlusion and simvastatin (20 mg/kg s.c) (n = 11) or vehicle (n = 9) were administered 15 min after. To evaluate the neuroprotective mechanisms of simvastatin, brain homogenates after 48 h were analyzed by two‐dimensional fluorescence Difference in Gel Electrophoresis (DIGE) technology. We confirmed that simvastatin reduced the infarct volume and improved neurological impairment at 48 h after the stroke in this model. Considering our proteomics analysis, 66 spots, which revealed significant differences between groups, were analyzed by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry allowing the identification of 27 proteins. From these results, we suggest that simvastatin protective effect can be partly explained by the attenuation of the oxidative and stress response at blood–brain barrier level after cerebral ischemia. Interestingly, analyzing one of the proteins (HSP75) in plasma from stroke patients who had received simvastatin during the acute phase, we confirmed the results found in the pre‐clinical model.

     

Breeding for flavour of fresh market tomato: sources for increasing acid content

Breeding programs in tomato for fresh consumption have concluded in very productive varieties/hybrids with an extraordinary external quality. However, internal quality has not been a priority objective in these breeding programs, so present products have a lack of important internal quality properties. Thus, internal and nutritional improvement including taste and organoleptyc characteristics are important breeding objectives at present. A screening trial to identify sources for internal quality improvement by increasing acid content was carried out. 12 accessions of Lycopersicon esculentum and 8 of L. pimpinellifolium were tested with that purpose. Content in citric, malic, oxalic and fumaric acid by HPLC, soluble solids content (SSC)(1 Brix) by refractometry and total acidity by titration with NaOH were measured. Sources for high citric, malic and fumaric acid content were found to begin those breeding programs. Results could possibly suggest an independent genetic control for every acid.