Molecular characterisation of bovine faecal Escherichia coli shows persistence of defined ampicillin resistant strains and the presence of class 1 integrons on an organic beef farm

Antimicrobial use is heavily restricted on organic farms; however, few studies have been conducted to investigate the impact this has on the epidemiology of resistance in pathogenic and commensal bacteria. We investigated the persistence of antimicrobial resistant Escherichia coli within an organic beef herd over a period of 28 months. Faecal samples collected monthly from three calf cohorts and annually from adult cattle and environmental samples, were screened for the presence of ampicillin, apramycin and nalidixic acid resistant E. coli. The prevalence of ampicillin resistance ranged from 27.3 to 40.7% in the annual herd and environmental samplings (n=22-55) and was greater in the calf cohorts, with a peak cohort prevalence of >47% in all 3 years (n=16-18). Apramycin and nalidixic acid resistant E. coli were rare. Pulsed-field gel electrophoresis (PFGE) identified 10 main genotype groups within the herd, with evidence of strain transmission between different livestock groups, animal species and years. Multiple resistance was found in >44% of isolates tested, with ampicillin, neomycin, sulphamethoxazole and tetracycline carriage the commonest phenotype identified. PCR detected the presence of class 1 integrons in <5% of resistant isolates, 6/7 of which were of cattle origin. These data demonstrate that ampicillin resistant E. coli was common on the farm despite restricted antimicrobial use, although strain diversity was low. Persistence of defined genotype groups was observed between years, together with the transmission of resistant strains between different animal species on the farm.     

The molecular identification and genetic diversity of economically important wireworm species (Coleoptera: Elateridae) in Canada

Click beetle larvae (wireworms) are significant crop pests in Europe and North America. In Canada, there are ~30 economically important species which are morphologically difficult to identify, but for which sequence data are lacking. Accurate knowledge of damage-causing species and the population genetics and phylogeography of elaterids will provide insight into their sustainable management. Here, we use interspecific variation in mitochondrial 16S rRNA as a robust method of identification, consider the intra- and interspecific genetic variation of some important Canadian wireworm pests and assess the genetic structure and isolation by distance for a re-emerging major pest species, Hypnoidus bicolor Eschscholtz. Wireworms were sampled from Canada and the USA, identified as morphospecies, and sequenced at the 16S rRNA region (294–442 bp). Within some species unusually high intraspecific genetic distances between samples suggested the possibility of cryptic wireworm species or misidentifications, though this was <1 % for most species. Phylogenetic analyses gave some indication of the likely identity of these ambiguous samples. There was a significant correlation between genetic and geographic distance and significant genetic structuring within and between H. bicolor populations, which appeared to be composed of two species comprising several haplotypes. These data provide a starting point for determining the distribution of damage-causing species throughout Canada. The inclusion of data from other nuclear and mitochondrial loci, and use of sequence data from known adult samples, would further aid identification and relationships of wireworm species.     

The theropod ancestry of birds: new evidence from the late cretaceous of madagascar

A partial skeleton of a primitive bird, Rahona ostromi, gen. et sp. nov., has been discovered from the Late Cretaceous of Madagascar. This specimen, although exhibiting avian features such as a reversed hallux and ulnar papillae, retains characteristics that indicate a theropod ancestry, including a pubic foot and hyposphene-hypantra vertebral articulations. Rahona has a robust, hyperextendible second digit on the hind foot that terminates in a sicklelike claw, a unique characteristic of the theropod groups Troodontidae and Dromaeosauridae. A phylogenetic analysis places Rahona with Archaeopteryx, making Rahona one of the most primitive birds yet discovered.     

A long-snouted predatory dinosaur from africa and the evolution of spinosaurids

Fossils discovered in Lower Cretaceous (Aptian) rocks in the Tenere Desert of central Niger provide new information about spinosaurids, a peculiar group of piscivorous theropod dinosaurs. The remains, which represent a new genus and species, reveal the extreme elongation and transverse compression of the spinosaurid snout. The postcranial bones include blade-shaped vertebral spines that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous.     

Unconditional quantum teleportation

Quantum teleportation of optical coherent states was demonstrated experimentally using squeezed-state entanglement. The quantum nature of the achieved teleportation was verified by the experimentally determined fidelity Fexp = 0.58 +/- 0.02, which describes the match between input and output states. A fidelity greater than 0.5 is not possible for coherent states without the use of entanglement. This is the first realization of unconditional quantum teleportation where every state entering the device is actually teleported.     

Thermodynamics of calcite growth: baseline for understanding biomineral formation

The complexity of biomineralized structures suggests the potential of organic constituents for controlling energetic factors during crystal synthesis. Atomic force microscopy was used to investigate the thermodynamic controls on carbonate growth and to measure the dependence of step speed on step length and the dependence of critical step length on supersaturation in precisely controlled solutions. These data were used to test the classic Gibbs-Thomson relationship and provided the step edge free energies and free energy barriers to one-dimension nucleation for calcite. Addition of aspartic acid, a common component in biomineralizing systems, dramatically affected growth morphology and altered the magnitude of the surface energy.     

Influence of pig substitution on milk yield, litter weights, and milk composition of machine milked sows.

This study was conducted to 1) determine milk yield of sows that were machine milked up to four times daily; 2) determine the effect of pig substitution on milk yield; 3) assess litter weight changes for sows that are milked; and 4) determine milk composition. Eight sows were milked four times daily to d 51 postpartum. Sows either maintained their own litter or had a week-old replacement litter to replace 25-d-old pigs. Individual gland milk yields were obtained on random days throughout lactation, and different diameter and weighted teat cups were rotated so that all glands received all combinations. Composite milk samples were analyzed for fat, protein, and somatic cells. Milk yields peaked at about 19 d postpartum and declined to 45 d postpartum in sows with their own litter, whereas milk yields peaked earlier and had a more dramatic decline after fostering of a younger litter. Litter weights were 17.1 +/- 1.0 kg at farrowing with 13.6 +/- .6 pigs born alive. Final litter weights were 34.4 +/- 11.7 kg for sows with replacement litters and 74.4 +/- 13.5 kg for sows with their own litters, and numbers of pigs weaned were 6.5 +/- 1.3 and 9.7 +/- 1.5, respectively. Milk fat was influenced by route of oxytocin administration (6.53 +/- .12 for i.v. vs 7.21 +/- .19% for i.m. administration; P < .05). Milk fat percentage was highest on d 2 and declined to 13 d postpartum. Milk protein was influenced by time of day of milking (lowest at the fourth milking, 5.57 +/- .11%) and followed a pattern similar to that for milk fat. Milk protein was affected in a linear manner by milk yield, with highest protein associated with lowest milk yields. Somatic cells in milk were influenced by litter replacement (P < .05) and oxytocin administration (P < .01). There was a linear increase in somatic cells from about 8 x 10(6) cells/mL milk at d 2 to more than 12 x 10(6) cells/mL milk at d 51 postpartum. These results show that pig replacement affects the amount of milk obtained. Moreover, milk composition changes throughout lactation. However, milk removal from sows has a severe impact on litter weight gains, and in systems where sow's milk is needed for commercial purposes, pig supplementation is necessary.