Comparative analysis of two slc11 (Nramp) loci in Takifugu rubripes

To study the evolution of the solute carrier family 11 (slc11; formerly Nramp) protein, we isolated and characterized two paralogs from the pufferfish Takifugu rubripes (Fugu). These teleost genes, designated Fugu slc11a-a and Fugu slc11a-b, comprise open reading frames of 1743 nucleotides (581 amino acids) and 1662 nt (554 aa), respectively. The proteins are 81% similar, and both exhibit signature features of the slc11 family of proteins including 12 transmembrane domains, a conserved transport motif and a glycosylated loop. Both Fugu paralogs are more Slc11a2-like based on sequence homology and phylogenetic studies. Analysis of gene environment placed both in the proximity of multiple loci syntenic to human chromosome 12q13, that is, within a SLC11A2 gene environment. However, Fugu slc11a-a also gave one match with chromosome 2q35, where human SLC11A1 resides. Functional diversification was suggested by differences in tissue distribution and subcellular localization. Fugu slc11a-a exhibits a restricted expression profile and a complex subcellular localization, including LAMP1 positive late endosomes/lysosomes in transiently transfected mouse macrophages. Fugu slc11a-b is expressed ubiquitously and localizes solely to late endosomes/lysosomes. This comparative analysis extends our understanding of the evolution and function of this important family of divalent cation transporters. [Sequence data from this article have been deposited with the EMBL/GenBank Data Libraries under accession nos. AJ496547/8/9 and AJ496550.]     

Mating-Type Effect on CIS Mutations Leading to Constitutivity of Ornithine Transaminase in Diploid Cells of SACCHAROMYCES CEREVISIAE

Cis-acting regulatory mutations have been isolated that affect L-ornithine transaminase (OTAse), an enzyme catalyzing the second step of arginine breakdown in yeast. These mutations lead to constitutive synthesis of OTAse at various levels. Two different types of mutations have been recovered, both of which are tightly linked to the structural gene (cargB) for this enzyme. One type behaves as a classical operator-constitutive mutation similar to the cargB+O---1 mutation previously described (DUBOIS et al. 1978). The second type is peculiar in two respects: the higher level of constitutive OTAse synthesis and the expression of constitutivity in diploid cells. These mutations are designated cargB+Oh. They behave as usual operator-constitutive mutations in diploid strains homozygous for mating type (a/a or alpha/alpha), but the constitutivity is strongly reduced in a/alpha diploid cells.     

Selenium addition alters mercury uptake,bioavailability in the rhizosphere and root anatomy of rice (Oryza sativa)

Background and Aims

Mercury (Hg) is an extremely toxic pollutant, especially in the form of methylmercury (MeHg), whereas selenium (Se) is an essential trace element in the human diet. This study aimed to ascertain whether addition of Se can produce rice with enriched Se and lowered Hg content when growing in Hg-contaminated paddy fields and, if so, to determine the possible mechanisms behind these effects.

Methods

Two cultivars of rice (Oryza sativa, japonica and indica) were grown in either hydroponic solutions or soil rhizobags with different Se and Hg treatments. Concentrations of total Hg, MeHg and Se were determined in the roots, shoots and brown rice, together with Hg uptake kinetics and Hg bioavailability in the soil. Root anatonmy was also studied.

Key Results

The high Se treatment (5 μg g^–1) significantly increased brown rice yield by 48 % and total Se content by 2·8-fold, and decreased total Hg and MeHg by 47 and 55 %, respectively, compared with the control treatments. The high Se treatment also markedly reduced ‘water-soluble’ Hg and MeHg concentrations in the rhizosphere soil, decreased the uptake capacity of Hg by roots and enhanced the development of apoplastic barriers in the root endodermis.

Conclusions

Addition of Se to Hg-contaminated soil can help produce brown rice that is simultaneously enriched in Se and contains less total Hg and MeHg. The lowered accumulation of total Hg and MeHg appears to be the result of reduced bioavailability of Hg and production of MeHg in the rhizosphere, suppression of uptake of Hg into the root cells and an enhancement of the development of apoplastic barriers in the endodermis of the roots.     

Are gardens effective in butterfly conservation? A case study with the pipevine swallowtail, <Emphasis Type="Italic">Battus philenor</Emphasis>

Gardens with nectar sources and larval host plants have been proposed to stem the decline in butterfly abundance caused by habitat loss. However, no study has provided evidence that gardens benefit butterflies. We examined the use of natural sites and gardens in the San Francisco bay area by the butterfly, Battus philenor. We found that natural sites were more likely to attract adult B. philenor, received more oviposition, and had higher juvenile survival than gardens sites. Butterflies were more likely to be present in gardens with established populations of the host plant, Aristolochia californica, growing in the sun. Battus philenor are unlikely to visit gardens with host plants planted within the past 7 years. Gardens between the ages of 8–40 years received oviposition, but did not always support completion of larval development of B. philenor. In gardens with host plants over 40 years of age, B. philenor consistently survived from egg to the adult stage. Natural enemy induced mortality of eggs did not differ between garden and natural sites, but overall egg survival was lower in gardens than at natural sites. It is unlikely that gardens serve as 'refugia' for B. philenor in years when populations in natural sites experience low survival or low fecundity. Even in gardens capable of supporting larvae to maturity, the density of eggs and survival rates were lower than in natural populations of the host plant suggesting that gardens were not optimal habitats. Therefore, without evidence that juvenile abundance and survival rates in gardens matches or exceeds that in natural sites, it is most likely that gardens act as population sinks for B. philenor.     

Basal level of human platelet prostaglandins: PGE1 is more elevated than PGE2

Radioimmunoassays of platelet prostaglandins E₁ and F_1α in platelet rich plasma or platelet suspension, demonstrate that both PGE₁ and PGF_1α are present at higher concentrations than prostaglandins E₂ and F_2α. Gas chromatography — mass spectrometry determinations of prostaglandins E₁ and E₂ in resting washed platelets confirm this difference. Lastly, there is a greater incorporation of [1-¹⁴C] acetate into prostaglandins E₁ and F_1α compared to that into prostaglandins E₂ and F_2α.     

Pathogenesis and transmission of triple-reassortant swine H1N1 influenza viruses isolated before the 2009 H1N1 pandemic

The 2009 H1N1 pandemic influenza virus represents the greatest incidence of human infection with an influenza virus of swine origin to date. Moreover, triple-reassortant swine (TRS) H1N1 viruses, which share similar host and lineage origins with 2009 H1N1 viruses, have been responsible for sporadic human cases since 2005. Similar to 2009 H1N1 viruses, TRS viruses are capable of causing severe disease in previously healthy individuals and frequently manifest with gastrointestinal symptoms; however, their ability to cause severe disease has not been extensively studied. Here, we evaluated the pathogenicity and transmissibility of two TRS viruses associated with disease in humans in the ferret model. TRS and 2009 H1N1 viruses exhibited comparable viral titers and histopathologies following virus infection and were similarly unable to transmit efficiently via respiratory droplets in the ferret model. Utilizing TRS and 2009 H1N1 viruses, we conducted extensive hematologic and blood serum analyses on infected ferrets to identify lymphohematopoietic parameters associated with mild to severe influenza virus infection. Following H1N1 or H5N1 influenza virus infection, ferrets were found to recapitulate several laboratory abnormalities previously documented with human disease, furthering the utility of the ferret model for the assessment of influenza virus pathogenicity.     

Using identity-by-descent information in affected sib pairs to increase the efficiency of genetic association studies.

The aim of this study was to determine whether identity-by-descent (IBD) information for affected sib pairs (ASPs) can be used to select a sample of cases for a genetic case-control study which will provide more power for detecting association with loci in a known linkage region. By modeling the expected frequency of the disease allele in ASPs showing IBD sharing of 0, 1, or 2 alleles, and considering additive, recessive, and dominant disease models, we show that cases selected from IBD 2 families are best for this purpose, followed by those selected from IBD 1 families; least useful are cases selected from IBD 0 families.