Preserving genetic integrity in a hybridising world: are European Wildcats (Felis silvestris silvestris) in eastern France distinct from sympatric feral domestic cats?

We investigate the genetic profile of putative European Wildcats in north-eastern France, possessing the wildcat phenotype, but sampled in an area where they are sympatric with free-roaming domestic cats and, thus, are exposed to potential hybridisation. From a sample of 209 cats, the programme STRUCTURE clearly identified two distinct genetic clusters that corresponded to European Wildcats and domestic cats. The cats from these two clusters were clearly differentiated from each other (F _ST  = 0.16). However, the genotypes of some individual cats were split between the two clusters, indicative of genetic admixture. Our analysis demonstrates that a genetically distinct population of cats that possess the European Wildcat phenotype persists in north-eastern France, but that there is a low, yet real, risk of hybridisation with sympatric domestic cats. These European Wildcats warrant conservation efforts to protect their genetic integrity.     

Genome hypermethylation in Pinus silvestris of Chernobyl--a mechanism for radiation adaptation?

Adaptation is a complex process by which populations of organisms respond to long-term environmental stresses by permanent genetic change. Here we present data from the natural "open-field" radiation adaptation experiment after the Chernobyl accident and provide the first evidence of the involvement of epigenetic changes in adaptation of a eukaryote-Scots pine (Pinus silvestris), to chronic radiation exposure. We have evaluated global genome methylation of control and radiation-exposed pine trees using a method based on cleavage by a methylation-sensitive HpaII restriction endonuclease that leaves a 5' guanine overhang and subsequent single nucleotide extension with labeled [3H] dCTP. We have found that genomic DNA of exposed pine trees was considerably hypermethylated. Moreover, hypermethylation appeared to be dependent upon the radiation dose absorbed by the trees. Such hypermethylation may be viewed as a defense strategy of plants that prevents genome instability and reshuffling of the hereditary material, allowing survival in an extreme environment. Further studies are clearly needed to analyze in detail the involvement of DNA methylation and other epigenetic mechanisms in the complex process of radiation stress and adaptive response.     

Vakuolenkontraktion bei vollen Zellsäften an Zwiebelzellen vonTulipa silvestris undColchicum speciosum

Zusammenfassung Die Innenepidermis des die Zwiebel vonTulipa silvestris undColchicum speciosum umhüllenden ersten Laubblattes weist zwei Arten von Zellen auf, solche mit leeren speicherstofffreien Zellsäften und dazwischen Idioblasten mit vollen, d. h. speicherstofführenden Zellsäften. Die letzteren färben sich mit basischen Farbstoffen wesentlich intensiver an als erstere.Färbt manTulipa silvestris mit Neutralrot 110.000, pH 7,1, in aqua dest., so zeigt sich bei den vollen Zellsäften eine starke Vakuolenkontraktion, die jedoch keine gerundeten Menisken aufweist, sondern meist malachitartig eingeschnürte Tonoplasten zeigt. Ähnliche unregelmäßige Vakuolenkontraktion erhält man auch beiColchicum speciosum bei der gleichen Färbung. Nur sind hier die Tonoplasten ähnlich wie bei einer Krampfplasmolyse stark eingebuchtet.Bei Färbung mit Chrysoidin bei gleichem pH und gleicher Konzentration erhält man ein wesentlich anderes Bild. Die Menisken der kontrahierten Vakuolen sind in jedem Falle schön gerundet.Die Kontraktion erreicht mit Chrysoidin einen stärkeren Grad als mit Neutralrot. Die Vakuole nimmt beiTulipa silvestris in Neutralrot 90%, in Chrysoidin 81%, beiColchicum speciosum in Neutralrot 96% und in Chrysoidin 88% vom Zellvolumen ein.     

La fioritura di „Tulipa silvestris“ L. in rapporto alla nutrizione azotata

Many members of the Orchidaceae, the largest vascular plant family in Ecuador, are at risk of extinction. It was therefore considered important to establish an efficient way of clonal propagation based on somatic embryogenesis of Cattleya maxima, a native Ecuadorian orchid. To this end, we evaluated the effect on somatic embryo induction of 12 combinations of 2,4-dichlorophenoxyacetic acid and 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea, as well as three kinds of stresses. Protocorms produced 42% of embryogenic calli on 1/2 Murashige and Skoog (1/2 MS) medium, compared to 96.3% when protocorms were stressed for 6 h with 0.3 M NaCl, followed by cultivation on 1/2 MS medium supplemented with 0.1 mg L^? 1 2,4-D. Our data demonstrated that the combination of either salt (0.3 M NaCl) or osmotic stress (0.4 M sorbitol) with subculture on 2,4-D (0.1 mg L^–1) medium significantly increases the percentage of protocorms with embryogenic callus. The number of embryos per embryogenic callus was not significantly different from that obtained after subculture in growth factor-free medium.     

Wild grapevine: silvestris,hybrids or cultivars that escaped from vineyards? Molecular evidence in Sardinia

Vitis vinifera ssp. silvestris, the spontaneous subspecies of V. vinifera L., is believed to be the ancestor of present grapevine cultivars. In this work, polymorphism at 13 SSR loci was investigated to answer the following key question: are wild plants (i) true silvestris, (ii) hybrids between wild and cultivated plants or (iii) or ‘escapes’ from vineyards? In particular, the objective of the present study was to identify truly wild individuals and to search for possible hybridization events. The study was performed in Sardinia, the second largest island in the Mediterranean Sea, which is characterized by a large and well‐described number of both grape cultivars and wild populations. This region was ideal for the study because of its spatial isolation and, consequently, limited contamination from outside material. The results of this study show that domesticated and wild grapevine germplasms are genetically divergent and thus are real silvestris. Pure lineages (both domesticated and wild) show very high average posterior probabilities of assignment to their own clusters, with a low level of introgression.     

Is there a future for wild grapevine (Vitis vinifera subsp. silvestris) in the Rhine Valley?

The wild grapevine, Vitis vinifera L. subsp. silvestris (Gmelin) Hegi, is considered to be an endangered taxon in Europe, mainly as a consequence of the introduction of pathogens from North America and of the destruction of its habitat. In the Rhine Valley, nearly all populations disappeared due to river management, the intensi.cation of forestry, and the introduction of phylloxera. After a growing awareness of the need to preserve endangered forest ecosystems, attempts to reintroduce wild grapevine in the Rhine Valley were performed, particularly in the French nature reserves Erstein and Offendorf since 1992. However, regular surveys of the plants indicate the rapid decline of the populations. In 2002, we proposed to summarise the knowledge accumulated after 10 years of experiments. Results indicate that from the initial 91 individuals planted in 1992, only 14 survived in 2002 (2 in Erstein, 12 in Offendorf). The failure of the experiment may be explained by several factors: unsuitable sites (too shady, absence of support for the young plants), absence of monitoring, vandalism or predation. According to these results and recent knowledge of the ecology of the plant and of vines in general, new transplantation experiments are proposed in which the plants will be monitored during their establishment in the forests. The success of this second transplant (50 plants per reserve) will be enhanced by restoration projects of the Rhine River dynamics, with partial re-.ooding. Floods should help to avoid, or at least to reduce, pest and disease expansion on future adult plants.     

Zucker,Cyclite und organische Säuren des Cambialsaftes von Pinus silvestris L., Picea Abies Karst. und Abies alba Mill

Summary Samples of cambial sap from each of the three coniferous species Pinus sylvestris L., Picea Abies Karst. and Abies alba Mill. were taken at the time the trees were coming into bud and analysed for low molecular weight carbohydrates, cyclitols and organic acids. They all contained the same free sugars and cyclitols, but in markedly different proportions. Quantitative analyses were carried out for glucose, fructose, sucrose, raffinose, myo-inositol, D-inositol, pinitol, sequoyitol and coniferin.The three main components of the organic acid fractions-quinic acid, shikimic acid and malic acid—were determined quantitatively. The amount of quinic acid greatly exceeded the amount of all the other acids in all three species. ¹⁴C-labelled quinic acid applied to the cut ends of Pinus sylvestris needles was transported to the twig. There was no conversion of quinic acid to shikimic acid over short periods of time.     

Crossing the Rhine: a potential barrier to wildcat (<Emphasis Type="Italic">Felis silvestris silvestris</Emphasis>) movement?

The European wildcat (Felis silvestris silvestris) underwent a severe decline across Europe in the early twentieth century. Remaining populations are often very small and isolated, though there are indications that wildcat populations are currently expanding their range. However, linear landscape elements such as rivers and roads are thought to present barriers to dispersal, inhibiting gene flow and, thus, affecting the recolonization process. In this study, we investigated the fine-scale genetic structure of wildcats in the Upper Rhine Valley. We specifically analysed wildcats on both sides of the Rhine River by genotyping 55 individual wildcats, using 20 microsatellite loci. Genetic differentiation was weak and positive spatial autocorrelation was found up to a distance of 10 km (females: 5 km, males: 10 km) indicating substantial gene flow among sampling sites. High levels of gene flow, even across the Rhine River, indicated that the water body itself does not necessarily have a strong barrier effect, which is in contrast to other studies. Our findings could best be explained by the populations’ history, a local extinction east of the River Rhine and a current ongoing population expansion. Our study highlights that potential barriers, such as rivers, may have different effects in different local wildcat populations and that the history of the populations is important to interpret genetic results. As many wildcats still occur in isolated and patchy forest fragments, maintaining connectivity between populations is crucial to ensure their viability in the long term.     

Morphology and development of the cranium of Felis silvestris f. catus Linné 1758--a contribution to the comparative anatomy of the Carnivora. III: Ear region and occipital region

In Felis, the otic region of younger embryonic stages up to Felis 1 is characterized by extremely medial extended cochleae, compressing the basal plate to a slender trabeculum. As a result of a quite strong rostrad convergence of the long axis of the ear capsules, the Commissura praefacialis fuses with the Commissura orbitoparietalis laterally. Until now, this has been found in whales only. Continuing embryogenesis towards Felis 2, the cochlea moves laterally and slightly ventrally, so the angle of convergence between the whole Capsula otica and the skull base decreases. The problem of interpreting these positional changes of the Capsula otica during phylogenesis and ontogenesis is discussed in detail. Up to recent literature, there is a discussion about homology of the Foramen perilymphaticum and allied structures in reptiles referring to the openings in the Capsula otica in mammals. Configuration of these structures in fissiped carnivores and the appearance of a "limitating membrane" in Felis 2, gives reason for a new discussion of these problems. Composition of the Bulla tympani is a very important feature for investigation of phylogeny and systematics in fissiped carnivores. In Felis 2, there appears a caudal entotympanic, consisting of young cartilaginous tissue. The development of the caudal entotympanic has impact on 2 structures in the occipital region: The Lamina alaris and the Processus paracondyloideus. Felis 1 shows a distinct Lamina alaris and a short Processus paracondyloideus. With Felis 2, either element is reduced largely, probably to the extent as the caudal entotympanic develops.