A freshwater diet-derived C-14 reservoir effect at the Stone Age sites in the Iron Gates gorge

Human bones from single inhumation burials and artifacts made from terrestrial mammal (ungulate) bone found in direct association with the skeletons were obtained from the Stone Age site of Schela Cladovei situated just below the iron Gates Gorge of the River Danube. The results of stable isotope analyses of the human bone collagen are consistent with a heavy dependence on aquatic protein while radiocarbon dating of the samples reveals an offset of 300-500 years between the two sample types, indicating a freshwater reservoir effect in the human bone samples, Since protein consumption is by far the major source of nitrogen in the human diet we have assumed a linear relationship between delta(15)N and the level of aquatic protein in each individual's diet and derived a calibration for C-14 age offset versus delta(15)N which has been applied to a series of results from the site at Lepenski Vir within the gorge, The corrected C-14 ages (7310-6720 BP) are now consistent with the previous C-14 age measurements made on charcoal from related contexts (7360-6560 BP). In addition, the data indicate a change from a primarily aquatic to a mixed terrestrial/aquatic diet around 7100 BP and this may be argued as supporting a shift from Mesolithic to Neolithic. This study also has wider implications for the accurate dating of human bone samples when the possibility exists of an aquatic component in the dietary protein and strongly implies that delta(15)N analysis should be undertaken routinely when dating human bones

CNT/PDMS composite membranes for H2 and CH4 gas separation

Polydimethylsiloxane (PDMS) composites with different weight amounts of multi-walled carbon nanotubes (MWCNT) were synthesised as membranes to evaluate their gas separation properties. The selectivity of the membranes was investigated for the separation of H2 from CH4 gas species. Membranes with MWCNT concentrations of 1% increased the selectivity to H2 gas by 94.8%. Furthermore, CH4 permeation was almost totally blocked through membranes with MWCNT concentrations greater than 5%. Vibrational spectroscopy and X-ray photoelectron spectroscopy techniques revealed that upon the incorporation of MWCNT a decrease in the number of available Si–CH3 and Si–O bonds as well as an increase in the formation of Si–C bonds occurred that initiated the reduction in CH4 permeation. As a result, the developed membranes can be an efficient and low cost solution for separating H2 from larger gas molecules such as CH4

A functional correlate of severity in alternating hemiplegia of childhood

OBJECTIVE: Mutations in ATP1A3, the gene that encodes the α3 subunit of the Na(+)/K(+) ATPase, are the primary cause of alternating hemiplegia of childhood (AHC). Correlations between different mutations and AHC severity were recently reported, with E815K identified in severe and D801N and G947R in milder cases. This study aims to explore the molecular pathological mechanisms in AHC and to identify functional correlates for mutations associated with different levels of disease severity. METHODS: Human wild type ATP1A3, and E815K, D801N and G947R mutants were expressed in Xenopus laevis oocytes and Na(+)/K(+) ATPase function measured. Structural homology models of the human α3 subunit containing AHC mutations were created. RESULTS: The AHC mutations examined all showed similar levels of reduction in forward cycling. Wild type forward cycling was reduced by coexpression with any mutant, indicating dominant negative interactions. Proton transport was measured and found to be selectively impaired only in E815K. Homology modeling showed that D801 and G947 lie within or near known cation binding sites while E815 is more distal. Despite its effect on proton transport, E815K was also distant from the proposed proton transport route. INTERPRETATION: Loss of forward cycling and dominant negativity are common and likely necessary pathomechanisms for AHC. In addition, loss of proton transport correlated with severity of AHC. D801N and G947R are likely to directly disrupt normal Na(+)/K(+) binding while E815K may disrupt forward cycling and proton transport via allosteric mechanisms yet to be elucidated

Is There Genetic Diversity in the ‘Leucaena Bug’ \u3cem\u3eSynergistes jonesii\u3c/em\u3e Which May Reflect Ability to Degrade Leucaena Toxins?

Leucaena leucocephala, a nutritionally rich forage tree legume, contains a non-protein amino acid, mimosine, which is degraded by ruminal bacteria to toxic metabolites 3,4-DHP and 2,3-DHP resulting in goitre-like symptoms in animals, severely restricting weight gain. Raymond Jones, in the early 1980s, discovered the ‘leucaena bug’ in the rumen of goats in Hawaii that degraded these toxic DHP metabolites into non-toxic compounds (Jones and Lowry 1984) which was named Synergistes jonesii (Allison et al. 1992) Subsequently, a rumen inoculum containing S. jonesii was used as an ‘oral drench’ for cattle, kept in continuous culture (Klieve et al. 2002) and supplied to farmers to dose cattle foraging on leucaena. Studies on Queensland herds that received this oral drench showed that up to 50% of 44 herds grazing on leucaena had apparent subclinical toxicity based on high 3,4- and 2,3-DHP excretion in urine (Dalzell et al., 2012). In another study by Graham et al. (2013), a 16S rDNA nested PCR showed that rumen digesta from 6 out of 8 properties tested had a variant DNA profile from S. jonesii ATCC 78.1 strain, which suggested a different strain of the bacterium. It was postulated that either the continually cultured oral inoculum may have undergone genetic modification and/or that animals could harbor other DHP degrading bacteria or S. jonesii strains with differential DHP degrading potential (McSweeney et al. unpublished). The present study looks at changes in the 16S rDNA gene at the molecular level that may suggest divergence from the type strain S. jonesii 78.1 (ATCC) in Queensland cattle as well as in cattle and other ruminants, internationally. These changes can appear as discrete mutations or ‘single nucleotide polymorphisms’ (SNPs) and may be correlated to their ability to degrade DHP, relative to the type strain

Multibeam Maser Survey of methanol and excited OH in the Magellanic clouds: new detections and maser abundance estimates

‘The definitive version is available at www.blackwell-synergy.com.’ Copyright Blackwell Publishing DOI: 10.1111/j.1365-2966.2008.12888.xPeer reviewe

Proteolysis in Danish blue cheese during ripening

Proteolysis in Danish blue cheese was studied during 9 weeks' ripening. Levels of pH 4.6-soluble N as a percentage of total N increased from 7.2% to 25%, indicating extensive proteolysis. Urea-polyacrylamide gel electrophoretograms confirmed the extent of proteolysis through chymosin and plasmin action early in ripening, but later the action of Penicillium roqueforti proteinases became apparent. The proteolytic specificity of Penicillium roqueforti PR-R proteinases on αS1- and β-casein was determined in a model system. Regions most susceptible to proteinase action in αS1-casein were 6–40, 69–99, 124–147 and 155–199, with a total of 91 cleavage sites identified; regions in β-casein susceptible to proteolysis were 43–87, 101–119, 161–185 and 192–209 with a total of 118 cleavage sites identified. A large number of peptides was identified cheese extracts during 9 weeks ripening, principally from αS1-casein regions 1–40, 105–136 and 150–176 and β-casein regions 6–14, 46–68, 101–140 and 193–209

The anti-inflammatory effect of taurine on cardiovascular disease

Taurine is a non-protein amino acid that is expressed in the majority of animal tissues. With its unique sulfonic acid makeup, taurine influences cellular functions, including osmoregulation, antioxidation, ion movement modulation, and conjugation of bile acids. Taurine exerts anti-inflammatory effects that improve diabetes and has shown benefits to the cardiovascular system, possibly by inhibition of the renin angiotensin system. The beneficial effects of taurine are reviewed