Increased whole blood manganese concentrations observed in children with iron deficiency anaemia

A prospective observational study was carried out at Alder Hey Children's Hospital, Liverpool, England, UK on children aged 1–6 years attending the pathology department for routine blood tests (n = 225). Whole blood manganese concentrations were measured plus the following markers of iron status; haemoglobin, MCV, MCH, RBC count, ferritin, transferrin saturation and soluble transferrin receptors. Multiple regression analysis was performed, with blood manganese as the dependent variable and factors of iron status, age and gender as independent variables. A strong relationship between blood manganese and iron deficiency was demonstrated (adjusted R² = 34.3%, p < 0.001) and the primary contributing factors to this relationship were haematological indices and soluble transferrin receptors. Subjects were categorised according to iron status using serum ferritin, transferrin saturation and haemoglobin indices. Children with iron deficiency anaemia had higher median blood manganese concentrations (16.4 μg/L, range 11.7–42.4, n = 20) than children with iron sufficiency (11 μg/L, range 5.9–20.9, n = 59, p < 0.001). This suggests that children with iron deficiency anaemia may be at risk from manganese toxicity (whole blood manganese >20 μg/L), and that this may lead to neurological problems. Treatment of iron deficiency in children is important both to improve iron status and to reduce the risk of manganese toxicity.     

Coa1 links the Mss51 post-translational function to Cox1 cofactor insertion in cytochrome c oxidase assembly

The assembly of cytochrome c oxidase (CcO) in yeast mitochondria is shown to be dependent on a new assembly factor designated Coa1 that associates with the mitochondrial inner membrane. Translation of the mitochondrial-encoded subunits of CcO occurs normally in coa1Delta cells, but these subunits fail to accumulate. The respiratory defect in coa1Delta cells is suppressed by high-copy MSS51, MDJ1 and COX10. Mss51 functions in Cox1 translation and elongation, whereas Cox10 participates in the biosynthesis of heme a, a key cofactor of CcO. Respiration in coa1Delta and shy1Delta cells is enhanced when Mss51 and Cox10 are coexpressed. Shy1 has been implicated in formation of the heme a3-Cu(B) site in Cox1. The interaction between Coa1 and Cox1, and the physical and genetic interactions between Coa1 and Mss51, Shy1 and Cox14 suggest that Coa1 coordinates the transition of newly synthesized Cox1 from the Mss51:Cox14 complex to the heme a cofactor insertion involving Shy1. coa1Delta cells also display a mitochondrial copper defect suggesting that Coa1 may have a direct link to copper metallation of CcO.     

Enzymes regulating the accumulation of active oxygen species during the hypersensitive reaction of bean to Pseudomonas syringae pv. phaseolicola

Changes in the activities of superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC 1.11.1.7) and catalase (CAT; EC 1.11.1.6) which regulate the persistence of active oxygen species (AOS) were examined in leaves of bean (Phaseolus vulgaris L. cv. Tendergreen) undergoing compatible and incompatible interactions to race 6 and race 3 strains, respectively, of the halo-blight bacterium Pseudomonas syringae pv. phaseolicola. Resistance of cv. Tendergreen to race 3 is determined by the R3 gene and was expressed by a hypersensitive reaction (HR) which was associated with a rapid increase in lipid peroxidation between 8 and 12 h after inoculation. Five main isoforms of SOD were resolved by native polyacrylamidegel electrophoresis (PAGE). Major changes were found in the activities of the cytosolic Cu, Zn-SOD3 and Cu, ZnSOD5 isoforms, which increased by 6 h after inoculation with race 3, and the possibly peroxisomal MnSOD2 isoform, which decreased rapidly in tissue undergoing the HR. Three further minor isoforms of SOD showed a strong increase in activity during the HR. A low level of extracellular SOD activity was also resolved; two isoforms, one of which increased dramatically in activity during the HR, were detected within intercellular fluids recovered from inoculation sites. Fewer changes in SOD activities were found during the compatible interaction to race 6, and they did not occur until 16 h after inoculation. In tissue around infiltration sites, no decrease in the activity of Mn-SOD2 was observed but slight increases in some other isoforms were found. Four groups of POD isoforms were detected in both 3,3-diaminobenzidine/H₂O₂-and o-dianisidine/H₂O₂-stained PAGE gels. Significant changes in activity were again associated with development of the HR. In particular, by 2 h after inoculation, increases in POD3a, b and c isoforms were detected within total soluble extracts and also in POD3c within intercellular fluids (no other isoform was found in the apoplasm). By contrast, POD1 and POD2 activities generally declined following inoculation. The principal change in activity in tissues surrounding infiltration sites was an increase in POD3 isoforms following inoculation with race 3. Measurements of total activity showed a decrease in CAT activity as early as 2 h after inoculation, followed by a recovery after 8 h and a further decrease as infiltrated tissue collapsed during the HR. A more-gradual decline in CAT activity was observed at sites undergoing the compatible interaction and also in tissue surrounding inoculation sites. The spatial and temporal changes detected in activities of CAT and isoforms of SOD and POD clearly demonstrate the complexity and potential subtlety of control of the production and persistence of AOS in bean following microbial challenge. The generation of AOS through HR-specific, early increases in extra-cellular POD and SOD isoforms is discussed.This work was supported in part by the scientific Research Foundaation (OTKA F 5082), the foundation for Hungarian science, a british council scolership to A.L.A and the U.K. Agricultural and food Reaserch council.     

Efficient genetic transformation of red raspberry,Rubus ideaus L.

We have developed an efficient transformation system for red raspberry (Rubus ideaus L.) using Agrobacterium mediated gene transfer. Using this system we have successfully introduced a gene that encodes an enzyme, S-adenosylmethionine hydrolase (SAMase), in raspberry cultivars Meeker (MK), Chilliwack (CH) and Canby (CY). Leaf and petiole expiants were inoculated with disarmed Agrobacterium tumefaciens strain EHA 105 carrying either of two binary vectors, pAG1452 or pAG1552, encoding gene sequences for SAMase under the control of the wound and fruit specific tomato E4 promoter. Primary shoot regenerants on selection medium were chimeral containing both transformed and non-transformed cells. Non-chimeral transgenic clones were developed by iterative culture of petiole, node and leaf explants, on selection medium, from successive generations of shoots derived from the primary regenerants. Percent recovery of transformants was higher with the selection marker gene hygromycin phosphotransferase (hpt), than with neomycin phosphotransferase (nptII). Transformation frequencies of 49.6%, 0.9% and 8.1% were obtained in cultivars Meeker, Chilliwack and Canby respectively from petiole expiants using hygromycin selection. Genomic integration of transgenes was confirmed by Southern hybridization. Transgenic plants from a total of 218 independent transformation events (161 MK, 4 CH, 53 CY) have been successfully established in soil.Abbreviations ACCO amincocyclopropane-1-carboxylic acid oxidase - AS acetosyringone - BA 6-benzylaminopurine - CH cultivar Chilliwack - CY cultivar Canby - cv cultivar - hpt hygromycin phosphotransferase - IBA indolebutyric acid - MK cultivar Meeker - npt II neomycin phosphotransferase - SAMase S-adenosylmethionine hydrolase - TDZ Thidiazuron (N-phenyl-N'-l,2,3-thidiazol-5-ylurea)