Mitochondrial DNA and nuclear microsatellites reveal high diversity and genetic structure in an avian top predator,the white‐tailed sea eagle,in central Europe

We analysed 123 white‐tailed sea eagles (Haliaeetus albicilla) from (primarily central) Europe with respect to variability and differentiation based on 499 bp of the mitochondrial control region and genotypes at seven unlinked nuclear microsatellites. Variability was high (overall expected heterozygosity, haplotype and nucleotide diversity being 0.70, 0.764 and 0.00698, respectively) and both marker systems showed a subdivision into two main genetic clusters (microsatellites) or haplogroups (mtDNA). In line with earlier analyses focusing on populations from northern and eastern Europe, as well as from Asia, we found a high level of admixture in Europe and no signs of a bottleneck – despite a severe decline of white‐tailed sea eagle populations during the 20^th century. Europe is thus a global stronghold for this species not only with respect to the number of breeding pairs but also regarding the proportion of species‐wide genetic diversity. Our dense sampling revealed a possibly clinal variation within central Europe from north‐west to south‐east that was reflected by the distribution of mtDNA haplotypes as well as the two microsatellite‐based clusters. This population differentiation in central Europe probably originated from a geographically structured postglacial colonization and was later enhanced by recent demographic fluctuations. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 727–737.     

THE REACTION OF WHEAT VARIETIES TO LOOSE SMUT AS DETERMINED BY EMBRYO, SEEDLING, AND ADULT PLANT TESTS

The possibility of using an embryo test as a means of determining the reaction of wheat varieties to loose smut ( Ustilago tritici (Pers.) Rostr.) has been investigated. Fifty-seven varieties were inoculated with two physiologic races by the partial vacuum method and the embryos, seedlings, and adult plants were examined for infection. Most of the varieties were fully susceptible to one or both races, and only ten showed real resistance to any one race. Braun R and Molinel proved almost immune to infection. The resistance in other varieties which showed no infection in the field was expressed as embryo susceptibility, i.e. the embryo became infected in much the same way as in field-susceptible varieties.
In the latter varieties infection passes from the embryo into the growing point of the young seedling. In the embryo-susceptible field-resistant varieties, infection does not pass from the scutellum and the growing point is therefore uninfected.
The reaction of most of the varieties tested was straightforward resistance or susceptibility, but in a few varieties a small proportion of the grains reacted differently from the majority. These reactions are discussed.     

Effects of Sucrose on Rooting and Senescence in Detached Raphanus sativus L. Cotyledons

Application of 0.5–4.0 per cent sucrose to excised radishcotyledons incubated in the light suppressed the formation ofroots, enhanced the rate of yellowing, and altered the locationof chlorophyll loss from the margin of the lamina to the petiolarregion in most of the cotyledons. These effects were not producedwhen osmotica such as mannitol or polyethylene glycol were used. A few cotyledons were able to root in the presence of sucroseand these showed enhanced yellowing at the margin. The numberof such cotyledons increased when they were incubated in waterfor the period during which primordium initiation begins, beforetransfer to sucrose. However, the pattern of yellowing in thepresence of sucrose was not affected by the repeated removalof the region of primordium development, suggesting that thepattern of senescence is not controlled by the formation ofroot primordia. The results are discussed in relation to the effects of lightand possible accumulation of carbohydrate on senescence androot formation in excised tissues.     

A Cell Culture System for Study of the Development of Toxoplasma gondii Bradyzoites

ABSTRACT. Toxoplasma gondii is a ubiquitous apicomplexan parasite and a major opportunistic pathogen under AIDS-induced conditions, where it causes encephalitis when the bradyzoite (cyst) stage is reactivated. A bradyzoite-specific Mab, 74.1.8, reacting with a 28 kDa antigen, was used to study bradyzoite development in vitro by immuno-electron microscopy and immunofluorescence in human fibroblasts infected with ME49 strain T. gondii . Bradyzoites were detected in tissue culture within 3 days of infection. Free floating cyst-like structures were also identified. Western blotting demonstrated the expression of bradyzoite antigens in these free-floating cysts as well as in the monolayer. Bradyzoite development was increased by using media adjusted to pH 6.8 or 8.2. The addition of γ-interferon at day 3 of culture while decreasing the total number of cysts formed prevented tachyzoite overgrowth and enabled study of in vitro bradyzoites for up to 25 days. The addition of IL-6 increased the number of cysts released into the medium and increased the number of cysts formed at pH 7.2. Confirmation of bradyzoite development in vitro was provided by electron microscopy. It is possible that the induction of an acute phase response in the host cell may be important for bradyzoite differentiation. This system should allow further studies on the effect of various agents on the development of bradyzoites.     

Soft Rot Erwinia Bacteria in the Atmospheric Bacterial Aerosol

Using a Casella High Volume Airborne Bacteria Sampler, the soft rot coliform bacteria Erwinia carotovora var. carotovora and E. carotovora var. atroseptica were caught from the open air during rainfall in mid to late summer, autumn and early winter, but not in late winter, spring or early summer. They were not found every time it rained, and never when the weather was dry. The bacteria were caught close to potato crops, but there were several occasions when they were found at sites where there were no such crops or at times of year after potato crops had been harvested. The sources of the organisms are uncertain, but those obtained close to potato crops may have originated there. The results are considered to provide further evidence that airborne spread and subsequent deposition of viable bacteria could cause contamination of Erwinia -free potato stocks, and suggest that rainfall is a major generator of the general atmospheric bacterial aerosol.     

The Effect of Sucrose on Primordium Development and on Protein and RNA Levels in Detached Cotyledons of Sinapis alba L.

Cotyledons of Sinapis alba cultured in the light on filter-papermoistened with water initiated root primordia within 2 daysafter detachment. These increased in size and penetrated thebase of the petiole after a further 3 days. Culture in sucrosesolution in the light inhibited root formation mainly by affectingthe extension phase when many primordia regressed resultingin a decline in the numbers of primordia per petiole. When cotyledonswere cultured in the dark no primordia were initiated in water,but sucrose promoted root formation. Levels of RNA rose to a peak value in the terminal petiole segmentat a time when primordia were being initiated in this region,protein reached a peak 2 days later. This pattern was much lessevident in the subterminal segments. It did not occur at allin cotyledons cultured in sucrose in the light where a smallinitial increase in RNA and protein was followed by a rapiddecline. The level of RNA and protein in the terminal segmentin light-cultured cotyledons in water was related to the numberof light periods given following detachment as was the percentageof cotyledons which formed roots. The effect of sucrose on RNAand protein content was less marked when cotyledons were transferredfrom sucrose to water instead of being maintained in sucrosethroughout. Sucrose clearly modifies the biochemical and structural changestaking place at the petiole base having particularly inhibitoryeffects on the extension phase of the primordia. The evidenceindicates that sucrose could be causing premature ageing ofcells forming the primordia.