Transport and metabolism of pyridoxine in rat liver

Evidence, obtained with in situ perfused rat liver, indicated that pyridoxine is taken up from the perfusate by a non-concentrative process, followed by metabolic trapping. These conclusions were reached on the basis of the fact that at low concentrations (0.125 μM), the ³H of [³H]pyridoxine accumulated against a concentration gradient, but high concentrations (333 μM) of pyridoxine or 4-deoxypyridoxine prevented this apparent concentrative uptake. Under no conditions did the tissue water : perfusate concentration ratio of [³H]pyridoxine exceed unity.The perfused liver rapidly converted the labeled pyridoxine to pyridoxine phosphate, pyridoxal phosphate and pyridoxamine phosphate and released a substantial amount of pyridoxal and some pyridoxal phosphate into the perfusate. Since muscle and erythrocytes failed to oxidize pyridoxine phosphate to pyridoxal phosphate, it is suggested that the liver plays a major role in oxidizing dietary pyridoxine and pyridoxamine as their phosphate esters to supply pyridoxal phosphate which then reaches to other organs chiefly as circulating pyridoxal.     

Fossil avian eggshell preserves ancient DNA

Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies. Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA (aDNA). We describe the successful isolation and amplification of DNA from fossil eggshell up to 19 ka old. aDNA was successfully characterized from eggshell obtained from New Zealand (extinct moa and ducks), Madagascar (extinct elephant birds) and Australia (emu and owl). Our data demonstrate excellent preservation of the nucleic acids, evidenced by retrieval of both mitochondrial and nuclear DNA from many of the samples. Using confocal microscopy and quantitative PCR, this study critically evaluates approaches to maximize DNA recovery from powdered eggshell. Our quantitative PCR experiments also demonstrate that moa eggshell has approximately 125 times lower bacterial load than bone, making it a highly suitable substrate for high-throughput sequencing approaches. Importantly, the preservation of DNA in Pleistocene eggshell from Australia and Holocene deposits from Madagascar indicates that eggshell is an excellent substrate for the long-term preservation of DNA in warmer climates. The successful recovery of DNA from this substrate has implications in a number of scientific disciplines; most notably archaeology and palaeontology, where genotypes and/or DNA-based species identifications can add significantly to our understanding of diets, environments, past biodiversity and evolutionary processes.     

Hepcidin expression and iron transport in alveolar macrophages

Alveolar macrophages express many proteins important in iron homeostasis, including the iron importer divalent metal transport 1 (DMT1) and the iron exporter ferroportin 1 (FPN1) that likely participate in lung defense. We found the iron regulatory hormone hepcidin (HAMP) is also produced by alveolar macrophages. In mouse alveolar macrophages, HAMP mRNA was detected at a low level when not stimulated but at a high level when exposed to lipopolysaccharide (LPS). LPS also affected the mRNA levels of the iron transporters, with DMT1 being upregulated and FPN1 downregulated. However, iron had no effect on HAMP expression but was able to upregulate both DMT1 and FPN1 in alveolar macrophages. IL-1 and IL-6, which are important in HAMP augmentation in hepatocytes, also did not affect HAMP expression in alveolar macrophages. In fact, the LPS-induced alterations in the expression of HAMP as well as DMT1 and FPN1 were preserved in the alveolar macrophages isolated from IL-1 receptor or IL-6-deficient mice. When alveolar macrophages were loaded with transferrin-bound (55)Fe, the subsequent release of (55)Fe was inhibited significantly by LPS. In addition, treatment of these cells with either LPS or HAMP caused the diminishment of the surface FPN1. These findings are consistent with the current model that HAMP production leads to a decreased iron efflux. Our studies suggest that iron mobilization by alveolar macrophages can be affected by iron and LPS via several pathways, including HAMP-mediated degradation of FPN1, and that these cells may use unique regulatory mechanisms to cope with iron imbalance in the lung.     

Synthesis and receptor binding studies of halogenated N,N-dialkylel-(2-phenyl-1H-indol-3-yl)glyoxylamides to visualize peripheral benzodiazepine receptors with SPECT or PET

A library of halogenated 2-arylindolyl-3-oxocarboxamides was prepared to develop radioligands to visualize cerebral PBR by SPECT and PET imaging. In vitro evaluation showed that most of the synthesized compounds were selective,high-affinity PBR ligands with adequate lipophilicity (log D7.4 in the range of 1.6-2.4). The iodinated derivative 11 (Ki = 2.6 nM) and the fluorinated analog 26 (Ki = 6.2 nM) displayed higher affinity than reference compounds.     

Diversity of lepidopteran stem borers on monocotyledonous plants in eastern Africa and the islands of Madagascar and Zanzibar revisited

Surveys were completed in Eritrea, Ethiopia, Kenya, Madagascar, Mozambique, Tanzania, Uganda and Zanzibar to assess the lepidopteran stem borer species diversity on wild host plants. A total of 24,674 larvae belonging to 135 species were collected from 75 species of wild host plants belonging to the Poaceae, Cyperaceae and Typhaceae. Amongst them were 44 noctuid species belonging to at least nine genera, 33 crambids, 15 pyralids, 16 Pyraloidea species not yet identified, 25 tortricids and three cossids. The noctuid larvae represented 73.6% of the total number of larvae collected, with 66.3, 3.5 and 3.8% found on Poaceae, Cyperaceae and Typhaceae, respectively. The Crambidae, Pyralidae, Tortricidae and Cossidae represented 19.8, 1.9, 2.5 and 0.1% of the total larvae collected, respectively, with 90.4% of the Crambidae and Pyralidae collected from Poaceae, and 99.7% of the Tortricidae collected from Cyperaceae. The lepidopteran stem borer species diversity in the wild host plants was far more diverse than previously reported.     

Genetic Variations in SMAD7 Are Associated with Colorectal Cancer Risk in the Colon Cancer Family Registry

Background

Recent genome-wide studies identified a risk locus for colorectal cancer at 18q21, which maps to the SMAD7 gene. Our objective was to confirm the association between SMAD7 SNPs and colorectal cancer risk in the multi-center Colon Cancer Family Registry.

Materials and Methods

23 tagging SNPs in the SMAD7 gene were genotyped among 1,592 population-based and 253 clinic-based families. The SNP-colorectal cancer associations were assessed in multivariable conditional logistic regression.

Results

Among the population-based families, both SNPs rs12953717 (odds ratio, 1.29; 95% confidence interval, 1.12–1.49), and rs11874392 (odds ratio, 0.80; 95% confidence interval, 0.70–0.92) were associated with risk of colorectal cancer. These associations were similar among the population- and the clinic-based families, though they were significant only among the former. Marginally significant differences in the SNP-colorectal cancer associations were observed by use of nonsteroidal anti-inflammatory drugs, cigarette smoking, body mass index, and history of polyps.

Conclusions

SMAD7 SNPs were associated with colorectal cancer risk in the Colon Cancer Family Registry. There was evidence suggesting that the association between rs12953717 and colorectal cancer risk may be modified by factors such as smoking and use of nonsteroidal anti-inflammatory drugs.     

The activity of an ancient atypical protein kinase is stimulated by ADP-ribose in vitro

The piD261/Bud32 protein kinases are universal amongst the members of the Eucarya and Archaea. Despite the fact that phylogenetic analyses indicate that the piD261/Bud32 protein kinases descend directly from the primordial ancestor of the "eukaryotic" protein kinase superfamily, our knowledge of their physiological role is relatively fragmentary and largely limited to two eucaryal representatives: piD261/Bud32 from yeast and the p53-related protein kinase from humans. A deduced archaeal homolog, SsoPK5, is encoded by open reading frame sso0433 from the acidothermophile Sulfolobus solfataricus. Recombinantly-expressed SsoPK5 exhibited protein kinase activity, with a noticeable preference for phosphorylating proteins of acidic character and for Mn(2+) as cofactor. The protein kinase also can phosphorylate itself on serine and threonine residues. The activity of rSsoPK5 was increased several-fold upon preincubation with either millimolar concentrations of 5'-AMP or submicromolar concentrations of ADP-ribose. Other mono- and di-nucleotides were ineffective. While activation was enhanced by the presence of ATP, no autophosphorylation of the protein kinase could be detected prior to addition of exogenous substrate proteins. We therefore suggest that ADP-ribose acts by evoking a conformational transition in the enzyme. Activation by ADP-ribose represents a potential regulatory link between chromatin remodeling and the activity of SsoPK5.