Incongruence between chloroplast and species phylogenies in Eucalyptus subgenus Monocalyptus (Myrtaceae)

Seventy-eight polymorphic cpDNA (chloroplast DNA) characters were found in 13 closely related taxa from Eucalyptus series Amygdalinae (subgenus Monocalyptus) and seven potential outgroup taxa. The strict consensus of six cladograms generated from cpDNA data confirmed monophyly of Monocalyptus. However, cpDNA phylogeny within Monocalyptus was incongruent with taxonomic classification, being more related to geography, even when accessions were from divergent series. Monocalyptus cpDNA formed two major clades. On the island of Tasmania cpDNA was restricted to a single clade, exhibited very little variation, and was phylogenetically related to cpDNA found in central and western Victoria. In contrast, cpDNA of mainland monocalypt taxa was more variable, even within the Amygdalinae. Four out of six Tasmanian Amygdalinae species were polymorphic. The difference between cpDNA of replicates was often greater than differences between species from different series. The low level of cpDNA variation and extensive morphological intergradation between the Tasmanian endemics suggest recent speciation. However, the transfer of cpDNA through hybridization between lineages is the most likely explanation for the observed sharing of cpDNA across series. This study highlights that the geographical pattern to cpDNA variation in Eucalyptus may be an important source of information on past plant distributions in Australia.     

SIZE AND FLUCTUATING ASYMMETRY OF MORPHOMETRIC CHARACTERS IN MICE: THEIR ASSOCIATIONS WITH INBREEDING AND t-HAPLOTYPE

Abstract Fluctuating asymmetry (FA), a ubiquitous type of asymmetry of bilateral characters, often has been used as a measure of developmental instability in populations. FA is expected to increase in populations subjected to genetic stressors such as inbreeding or environmental stressors such as toxins or parasites, although results have not always been consistent. We tested whether FA in four skeletal size characters and mandible shape was greater in a population of wild‐derived mice reared in the laboratory and subjected to one generation of inbreeding (F = 0.25) versus that in an outbred group (F= 0.00). FA did not significantly differ between the inbred and outbred groups, despite the fact that these two groups differed dramatically in fitness under seminatural population conditions. As far as we know, this is the first study to evaluate the relationship between FA and inbreeding in wild house mice, and our general conclusion is opposite that of earlier work on laboratory inbred strains of mice and their hybrids. Size for two of the characters was significantly less in inbreds than in outbreds, however, and there was a significant difference between inbreds and outbreds in the signed differences of right and left sides in one character (humerus length). Some of the mice in both groups also were heterozygous or homozygous carriers of the t‐complex. Because mice carrying this chromosome 17 variant are known to have reduced fitness, we also tested whether they had greater FA than mice carrying non‐t‐haplotypes. The overall level of a composite FA index calculated from all four characters was in fact significantly higher in the t‐bearing mice. These combined results suggest that FA is not a generally sensitive proxy measure for fitness, but can be associated with fitness reductions for certain genetic stressors.     

Acetyl-l-carnitine attenuates neuronal damage in gerbils with transient forebrain ischeia only when givenBefore the insult

The underlying mechanisms leading to neuronal damage in cerebral ischemia are multifactoral. In this study, we evaluated the neuroprotective effects of acetyl-l-carnitine, a medication that may enhance metabolic recovery after cerebral ischemia. The 5-minute transient forebrain ischemia model in gerbils was used. Acetyl-l-carnitine was given 30 minutes before the insult in one set of animals and 30 minutes after the insult in a second set of animals with histological evaluation at 7 days (Group A) and 28 days (Group B). Damage assessment was done using a 4-point damage score and Mann-Whitney U test was used for statistical analysis. Compared to the controls, there was significant protection in the cerebral cortex, hippocampus and the striatum in animals treated with the medicationbefore the insult in Group A and Group B Post-ischemic therapy showed little evidence of neuronal protection in either group. Behavioral tests in the Group B animals showed no significant differences between the treated or the saline controls. Our study shows, that pre-ischemic treatment with acetyl-l-carnitine results in neuronal protection. This may have clinical significance in situations (such as bypass surgery) where treatment could be initiatedprior to the insult.     

Isolation and identification of previtamin D3 from the skin of rats exposed to ultraviolet irradiation.

The process of the photolytic activation of vitamin D precursor(s) in the skin has been elucidated by a detailed analysis of the products formed after ultraviolet light exposure. The photolytic product isolated from the skin of rats exposed to ultraviolet irradiation was identified as previtamin D3 by several criteria including its (a) characteristic ultraviolet absorption spectrum, (b) mass spectrum, and (c) thermal isomerization to vitamin D3, which itself was identified also by mass spectroscopy. Vitamin D3 per se was not formed by ultraviolet irradiation--vitamin D3 arises exclusively from the thermal conversion of previtamin D3. Detectable amounts of lumisterol3 or tachysterol3 were not seen.     

Acceptability of an oral contraceptive that reduces the frequency of menstruation: the tri-cycle pill regimen.

The frequency of menstruation was reduced to once every three months in 196 women by the continuous administration of the oral contraceptive pill, Minilyn, for 84 days (tri-cycle regimen). No pregnancies occurred. One hundred and sixty-one women (82%) welcomed the reduction in the number of periods with the associated freedom from menstrual and premenstrual symptoms, and many found the tri-cycle regimen easier to follow. Weight gain of more than 2 kg, irregular cycle control, especially in the first three months, breast tenderness, and headaches were the main side effects. Menstrual loss was unchanged or reduced in all but seven women. The doctors and nurses on the clinic staff were less enthusiastic about this regimen than the volunteers themselves.     

Impacts of a pesticide on pollinator species richness at different spatial scales

Pesticides are an important potential cause of biodiversity and pollinator decline. Little is known about the impacts of pesticides on wild pollinators in the field. Insect pollinators were sampled in an agricultural system in Italy with the aim of detecting the impacts of pesticide use. The insecticide fenitrothion was over 150 times greater in toxicity than other pesticides used in the area, so sampling was set up around its application. Species richness of wild bees, bumblebees and butterflies were sampled at three spatial scales to assess responses to pesticide application: (i) the ‘field’ scale along pesticide drift gradients; (ii) the ‘landscape’ scale sampling in different crops within the area and (iii) the ‘regional’ scale comparing two river basins with contrasting agricultural intensity. At the field scale, the interaction between the application regime of the insecticide and the point in the season was important for species richness. Wild bee species richness appeared to be unaffected by one insecticide application, but declined after two and three applications. At the landscape scale, the species richness of wild bees declined in vine fields where the insecticide was applied, but did not decline in maize or uncultivated fields. At the regional scale, lower bumblebee and butterfly species richness was found in the more intensively farmed basin with higher pesticide loads. Our results suggest that wild bees are an insect pollinator group at particular risk from pesticide use. Further investigation is needed on how the type, quantity and timing of pesticide application impacts pollinators.     

Sialic acid mutarotation is catalyzed by the Escherichia coli beta-propeller protein YjhT

The acquisition of host-derived sialic acid is an important virulence factor for some bacterial pathogens, but in vivo this sugar acid is sequestered in sialoconjugates as the alpha-anomer. In solution, however, sialic acid is present mainly as the beta-anomer, formed by a slow spontaneous mutarotation. We studied the Escherichia coli protein YjhT as a member of a family of uncharacterized proteins present in many sialic acid-utilizing pathogens. This protein is able to accelerate the equilibration of the alpha- and beta-anomers of the sialic acid N-acetylneuraminic acid, thus describing a novel sialic acid mutarotase activity. The structure of this periplasmic protein, solved to 1.5A resolution, reveals a dimeric 6-bladed unclosed beta-propeller, the first of a bacterial Kelch domain protein. Mutagenesis of conserved residues in YjhT demonstrated an important role for Glu-209 and Arg-215 in mutarotase activity. We also present data suggesting that the ability to utilize alpha-N-acetylneuraminic acid released from complex sialoconjugates in vivo provides a physiological advantage to bacteria containing YjhT.     

Preface

"Although few people die of pain,many people die in pain and even more live in pain"——IASP On October11,2004,International Association for the Study of Pain(IASP)