Climate Driven Life Histories: The Case of the Mediterranean Storm Petrel

Seabirds are affected by changes in the marine ecosystem. The influence of climatic factors on marine food webs can be reflected in long-term seabird population changes. We modelled the survival and recruitment of the Mediterranean storm petrel (Hydrobates pelagicus melitensis) using a 21-year mark-recapture dataset involving almost 5000 birds. We demonstrated a strong influence of prebreeding climatic conditions on recruitment age and of rainfall and breeding period conditions on juvenile survival. The results suggest that the juvenile survival rate of the Mediterranean subspecies may not be negatively affected by the predicted features of climate change, i.e., warmer summers and lower rainfall. Based on considerations of winter conditions in different parts of the Mediterranean, we were able to draw inferences about the wintering areas of the species for the first time.     

Thyroxine,methimazole, and thyroid microsomal autoantibody titres in hypothyroid Hashimoto's thyroiditis.

Ten hypothyroid patients with Hashimoto''s thyroiditis were treated with methimazole 30 mg in addition to thyroxine 0.15 mg daily. Another 10 hypothyroid patients with Hashimoto''s thyroiditis were given thyroxine 0.15 mg alone. After 22 weeks of treatment significant decreases in thyroid microsomal autoantibody titres were observed in both groups (p less than 0.01). There was no difference in the mean change in titre between the two groups. When the patients treated with methimazole were subsequently given thyroxine 0.15 mg alone for a further 22 weeks no additional change in titre was observed. The data suggest that thyroxine, by normalising serum thyroid stimulating hormone concentrations, may reduce the autoantigenic properties of the thyrocytes with a subsequent decrease in autoantibody titres.     

Developmental Exposure to Fluoxetine Modulates the Serotonin System in Hypothalamus

The selective serotonin reuptake inhibitor (SSRI) fluoxetine (FLU, Prozac®) is commonly prescribed for depression in pregnant women. This results in SSRI exposure of the developing fetus. However, there are knowledge gaps regarding the impact of SSRI exposure during development. Given the role of serotonin in brain development and its cross-talk with sex hormone function, we investigated effects of developmental exposure to pharmacologically relevant concentrations of FLU (3 and 30 nM (measured)) on brain neurotransmitter levels, gonadal differentiation, aromatase activity in brain and gonads, and the thyroid system, using the Xenopus tropicalis model. Tadpoles were chronically exposed (8 weeks) until metamorphosis. At metamorphosis brains were cryosectioned and levels of serotonin, dopamine, norepinephrine, and their metabolites 5-hydroxyindoleacetic acid, 3,4-dihydroxyphenylacetic acid, and homovanillic acid were measured in discrete regions (telencephalon, hypothalamus and the reticular formation) of the cryosections using high-performance liquid chromatography. Exposure to 30 nM FLU increased the concentration of 5-hydroxyindoleacetic acid in hypothalamus compared with controls. FLU exposure did not affect survival, time to metamorphosis, thyroid histology, gonadal sex differentiation, or aromatase activity implying that the effect on the serotonergic neurotransmitter system in the hypothalamus region was specific. The FLU concentration that impacted the serotonin system is lower than the concentration measured in umbilical cord serum, suggesting that the serotonin system of the developing brain is highly sensitive to in utero exposure to FLU. To our knowledge this is the first study showing effects of developmental FLU exposure on brain neurochemistry. Given that SSRIs are present in the aquatic environment the current results warrant further investigation into the neurobehavioral effects of SSRIs in aquatic wildlife.     

Calcium transport sensitive to ruthenium red in cytochrome oxidase vesicles reconstituted with mitochondrial proteins

We describe a calcium transport that is sensitive to ruthenium red in liposomes reconstituted with mitochondrial extracts. This system is able to build an internally negative membrane potential, which allows the electrogenic influx of Ca²⁺ and Sr²⁺. Proteins with molecular weights higher than 35 kDa were incorporated to the vesicles, and enhanced the accumulation of the cation in an energy-dependent fashion.     

Regional assignment of the human uroporphyrinogen III synthase (UROS) gene to chromosome 10q25.2→q26.3

Summary Uroporphyrinogen III synthase [UROS; hydroxymethylbilane hydro-lyase (cyclizing), EC 4.2.1.75] is the fourth enzyme in the human heme biosynthetic pathway. The recent isolation of the cDNA encoding human UROS facilitated its chromosomal localization. Human UROS sequences were specifically amplified by the polymerase chain reaction (PCR) from genomic DNA of two independent panels of human-rodent somatic cell hybrids. There was 100% concordance for the presence of the human UROS PCR product and human chromosome 10. For each of the other chromosomes, there was 19%–53% discordance with human UROS. The chromosomal assignment was confirmed by Southern hybridization analysis of DNA from somatic cell hybrids with the full-length UROS cDNA. Using human-rodent hybrids containing different portions of human chromosome 10, we assigned the UROS gene to the region 10q25.2 q26.3.     

DNA polymerase I activity in Escherichia coli is influenced by spot 42 RNA.

We have shown that the level of DNA polymerase I (Pol I) activity in Escherichia coli is influenced by the level of a 109-nucleotide RNA, spot 42 RNA. Deletion of the gene for spot 42 RNA results in a 20 to 25% decrease in Pol I activity, as assayed by nucleotide incorporation in cell extracts and a decrease in the ability of cells to grow in the presence of the DNA-alkylating agent methyl methanesulfonate. Also, a physiological reduction of the level of spot 42 RNA, by growth in media containing poor carbon sources, results in a corresponding decrease in Pol I activity. Conversely, overproduction of spot 42 RNA results in a 10 to 15% increase in Pol I activity in vitro. Thus, changes in the amount of spot 42 RNA result in relatively small but significant changes in Pol I activity.