Data from: Geographical parthenogenesis and population genetic structure in the alpine species Ranunculus kuepferi (Ranunculaceae)

Geographical parthenogenesis describes the enigmatic phenomenon that asexual organisms have larger distribution areas than their sexual relatives, especially in previously glaciated areas. Classical models suggest temporary advantages to asexuality in colonization scenarios because of uniparental reproduction and clonality. We analyzed population genetic structure and self-fertility of the plant species Ranunculus kuepferi on 59 populations from the whole distribution area (European Alps, Apennines and Corsica). Amplified fragment length polymorphisms (AFLPs) and five microsatellite loci revealed individual genotypes for all populations and mostly insignificant differences between diploid sexuals and tetraploid apomicts in all measures of genetic diversity. Low frequencies of private AFLP fragments/simple sequence repeat alleles, and character incompatibility analyses suggest that facultative recombination explains best the unexpectedly high genotypic diversity of apomicts. STRUCTURE analyses using AFLPs revealed a higher number of partitions and a stronger geographical subdivision for diploids than for tetraploids, which contradicts expectations of standard gene flow models, but indicates a reduction of genetic structure in asexuals. Apomictic populations exhibited high admixture near the sexual area, but appeared rather uniform in remote areas. Bagging experiments and analyses of pollen tube growth confirmed self-fertility for pollen-dependent apomicts, but self-sterility for diploid sexuals. Facultative apomixis combines advantages of both modes of reproduction: uniparental reproduction allows for rapid colonization of remote areas, whereas facultative sexuality and polyploidy maintains genetic diversity within apomictic populations. The density dependence of outcrossing limits range expansions of sexual populations

Listeriosis in fattening pigs caused by poor quality silage - a case report

Abstract Background Listeria (L.) monocytogenes as the causative agent of listeriosis in humans and different animal species, has its reservoir in the environment. It can be found in the gut and faeces of healthy pigs, but under certain circumstances it may cause clinical disease. Fatteners are usually not known to get affected by Listeria-associated septicaemia and enteritis. This case report shows, that L. monocytogenes should be part of the list of differential diagnoses, when fattening pigs suffer from haemorrhagic diarrhoea and septicaemia. Case presentation Here, we report of an episode of fatal listeriosis in fattening pigs in a piglet producing farm in Lower Austria, which was combined with a fattening unit with space for 450 fatteners. The mortality rate resulted in 7.8% among fattening pigs after suffering from clinical symptoms such as anorexia, bloody diarrhoea and increased body temperature. Two fattening pigs with clinical symptoms and maize silage samples were used for further diagnostics. L. monocytogenes were isolated from serosa samples of the pigs and in the corresponding fed maize silage. One animal was positively tested for Brachyspira hyodysenteriae, which may have also been involved in the development of colitis. Immunohistochemically, L. monocytogenes could be detected in high amounts in lymphatic tissue of the gut. Molecular biological characterisation of the L. monocytogenes isolates from pigs and maize silage resulted in an identical DNA-fingerprint assigned to sequence type (ST) 21. Additionally, a high content of deoxynivalenol (3000 parts per billion) was found in maize silage. Therefore, the maize silage produced under inappropriate ensilaging conditions in a silo, was most likely the source of infection. Antimicrobial therapy with amoxicillin led to a fast cure of the remaining affected fatteners. Conclusion To conclude, we were able to show, that L. monocytogenes can cause clinical disease in finishing pigs, which may have been a result of immunosuppression due to high deoxynivalenol exposure. When feeding silage it is important that all ensilaging procedures occur under appropriate anaerobic conditions to guarantee suppression of listerial growth

Inflorescences of alpine cushion plants freeze autonomously and may survive subzero temperatures by supercooling

Freezing patterns in the high alpine cushion plants Saxifraga bryoides, Saxifraga caesia, Saxifraga moschata and Silene acaulis were studied by infrared thermography at three reproductive stages (bud, anthesis, fruit development). The single reproductive shoots of a cushion froze independently in all four species at every reproductive stage. Ice formation caused lethal damage to the respective inflorescence. After ice nucleation, which occurred mainly in the stalk or the base of the reproductive shoot, ice propagated throughout that entire shoot, but not into neighboring shoots. However, anatomical ice barriers within cushions were not detected. The naturally occurring temperature gradient within the cushion appeared to interrupt ice propagation thermally. Consequently, every reproductive shoot needed an autonomous ice nucleation event to initiate freezing. Ice nucleation was not only influenced by minimum temperatures but also by the duration of exposure. At moderate subzero exposure temperatures (−4.3 to −7.7 °C) the number of frozen inflorescences increased exponentially. Due to efficient supercooling, single reproductive shoots remained unfrozen down to −17.4 °C (cooling rate 6 K h−1). Hence, the observed freezing pattern may be advantageous for frost survival of individual inflorescences and reproductive success of high alpine cushion plants, when during episodic summer frosts damage can be avoided by supercooling

Short-Chain Fatty Acids Modulate Permeability, Motility and Gene Expression in the Porcine Fetal Jejunum Ex Vivo

Postnatally, short-chain fatty acids (SCFA) are important energetic and signaling agents, being involved in host nutrition, gut imprinting and immune and barrier function. Whether SCFA exert similar effects during the late fetal phase has been insufficiently elucidated. This study aimed to evaluate whether the fetal jejunum senses SCFA and whether SCFA modify the muscle tension and epithelial permeability and related signaling in jejunal tissue from the porcine fetus in late gestation. Exposure of fetal jejunal tissue to a mix of SCFA (70 µmol/mL) in an organ bath for 20 min lowered the muscle tension. Moreover, SCFA decreased the transepithelial conductance while increasing the short-circuit current in the Ussing chamber, indicating reduced permeability and increased SCFA absorption. Gene expression in the tissues harvested from the Ussing chamber after 30 min indicated downregulation of the expression of receptors (i.e., FFAR2 and TLR2), MCT1 and tight-junction and adherens proteins, which may be a negative feedback response to the applied high SCFA concentration compared with the micromolar concentration detected in fetal gastric fluid. Taken together, our data demonstrate that the fetal jejunum senses SCFA, which trigger electrophysiological, muscle contraction and related gene transcription responses. Hence, SCFA may play a role in prenatal gut nutrition and imprinting

Humanized c-Myc mouse.

BACKGROUND: A given tumor is usually dependent on the oncogene that is activated in the respective tumor entity. This phenomenon called oncogene addiction provides the rationale for attempts to target oncogene products in a therapeutic manner, be it by small molecules, by small interfering RNAs (siRNA) or by antigen-specific T cells. As the proto-oncogene product is required also for the function of normal cells, this raises the question whether there is a therapeutic window between the adverse effects of specific inhibitors or T cells to normal tissue that may limit their application, and their beneficial tumor-specific therapeutic action. To address this crucial question, suitable mouse strains need to be developed, that enable expression of the human proto-oncogene not only in tumor but also in normal cells. The aim of this work is to provide such a mouse strain for the human proto-oncogene product c-MYC. PRINCIPAL FINDINGS: We generated C57BL/6-derived embryonic stem cells that are transgenic for a humanized c-Myc gene and established a mouse strain (hc-Myc) that expresses human c-MYC instead of the murine ortholog. These transgenic animals harbor the humanized c-Myc gene integrated into the endogenous murine c-Myc locus. Despite the lack of the endogenous murine c-Myc gene, homozygous mice show a normal phenotype indicating that human c-MYC can replace its murine ortholog. CONCLUSIONS: The newly established hc-Myc mouse strain provides a model system to study in detail the adverse effects of therapies that target the human c-MYC protein. To mimic the clinical situation, hc-Myc mice may be cross-bred to mice that develop tumors due to overexpression of human c-MYC. With these double transgenic mice it will be possible to study simultaneously the therapeutic efficiency and adverse side effects of MYC-specific therapies in the same mouse

Confirmation of homologous recombination and c-MYC2 expression in ES cell clones.

<p>(A) Genomic DNA of ES cell clones 1, 14, 18 and 19 and of wildtype ES cells (wt Bruce 4) was digested with <i>Eco</i>RI. Digested DNA was analyzed by Southern blotting with a 5′ probe and a 3′ probe. (wt) DNA fragment of the wildtype <i>c-Myc</i> locus; (rec.) DNA-fragment of recombined <i>hc-Myc</i> locus. (B) Protein extracts were prepared of ES cell clones 1, 14, 18 and 19 as well as of wildtype ES cells (wt Bruce 4) and of a human lymphoblastoid cell line (LCL 1.11). Human c-MYC2 (hu. c-MYC, ca. 62 kDa) was detected with antibody clone Y69. In wildtype ES cells murine c-MYC2 (mu. c-MYC, ca. 64 kDa) was detected. For loading control an antibody specific for glyceraldehyde-3-phosphat-dehydrogenase (GAPDH; ca. 36 kDa) was used. Western blot results were reproduced five times.</p

Mice transgenic for <i>hc-Myc</i>.

<p>(A) Example of a chimeric animal (chimerism of 60 to 70%) that was generated by injection of ES cell clone 14 into Balb/c blastocysts (day 3.5). (B) Chimeric animals were cross-bred to wildtype B6 mice yielding black progeny. Brother and sister matings of <i>hc-Myc</i> heterozygous mice (tested by PCR analysis) gave rise to <i>hc-Myc</i> homozygous offspring. The picture represents a PCR analysis of the genotypes of the offspring. For analysis genomic DNA was isolated from tail tissue. As controls genomic DNA of ES cell clones 1 and 14 was used. mu.c-Myc: PCR product of murine <i>c-Myc</i>. hc-Myc: PCR product of <i>hc-Myc</i>. (C) Detection of human c-MYC2 (hu. c-MYC, 62 kDa) in splenic cells of homozygous hc-Myc mice by Western blotting. In splenic cells of wildtype mice murine c-MYC2 was detected (mu. c-MYC, ca. 64 kDa). For positive control protein extracts from a human lymphoblastoid cell line (LCL 1.11) were used. Glyceraldehyde-3-phosphat-dehydrogenase (GAPDH, 36 kDa) was used as loading control.</p

hc-Myc mice have normal body and organ weights.

<p>Body weight (A) and organ weight of spleen (B), both kidneys (C) and liver (D) were analyzed of heterozygous (B6 hc-Myc^+/−, n = 5) and homozygous hc-Myc (B6 hc-Myc^+/+, n = 8) mice as well as of wildtype B6 mice (B6 wt, n = 8) at the age of 10 - 11 weeks. Each symbol represents one mouse. The mean weight is indicated in the graphs with a black line and shown at the top of the symbols. Where ever small differences were observed, they were not significant.</p