The use of predator-exclusion fencing as a management tool improves the breeding success of waders on lowland wet grassland

Waders breeding on lowland wet grassland have undergone dramatic declines across Europe in recent decades. Few species now achieve the levels of breeding success required for population stability and recovery, with predation from large mammals acting as a key compounding factor limiting nest survival and productivity. Predator management through lethal control is often controversial, yet alternative non-lethal methods are little tested in the context of grassland breeding waders. Excluding predators through the use of electric fences has led to improvements in nest and chick survival in other habitats. To test the applicability of this method to lowland wet grassland we constructed predator-exclusion fences on sites across the UK and, with Lapwing Vanellus vanellus as a study species, used historical and contemporary data to test whether excluding large mammalian predators leads to an increase in wader nest survival and productivity, and whether effects differ between fence designs. Lapwing nest survival was significantly higher in the presence of any type of predator-exclusion fence, with significantly fewer nests predated each day. Overall productivity also improved, with significantly higher numbers of chicks fledged per pair in years when fences were operational. Different designs and methods of powering fences resulted in different levels of success, with combination design fences and those powered by mains electricity performing best. Excluding large mammalian predators from areas of lowland wet grassland with predator-exclusion fencing successfully improves Lapwing nest survival and productivity, allowing breeding success to exceed the levels required for population recovery. Other wader species breeding in the same habitat are also likely to benefit from the increased protection from predation provided by fences. Predator-exclusion fencing is therefore an effective management tool for protecting restricted and declining populations of breeding waders on lowland wet grassland.     

Contextualising the Last Survivors: Population Structure of Marine Turtles in the Dominican Republic

Nesting by three species of marine turtles persists in the Dominican Republic, despite historic threats and long-term population decline. We conducted a genetic survey of marine turtles in the Dominican Republic in order to link them with other rookeries around the Caribbean. We sequenced a 740_bp fragment of the control region of the mitochondrial DNA of 92 samples from three marine turtle species [hawksbill (n = 48), green (n = 2) and leatherback (n = 42)], and incorporated published data from other nesting populations and foraging grounds. The leatherback turtle (Dermochelys coriacea) in the Dominican Republic appeared to be isolated from Awala-Yalimapo, Cayenne, Trinidad and St. Croix but connected with other Caribbean populations. Two distinct nesting populations of hawksbill turtles (Eremochelys imbricata) were detected in the Dominican Republic and exhibited interesting patterns of connectivity with other nesting sites and juvenile and adult male foraging aggregations. The green sea turtle (Chelonia mydas) has almost been extirpated from the Dominican Republic and limited inference could be made from our samples. Finally, results were compared with Lagrangian drifting buoys and published Lagrangian virtual particles that travelled through the Dominican Republic and Caribbean waters. Conservation implications of sink-source effects or genetic isolation derived from these complex inter-connections are discussed for each species and population.     

Defining the Vulnerable Period for Re-Establishment of Clostridium difficile Colonization after Treatment of C. difficile Infection with Oral Vancomycin or Metronidazole

Background

Clostridium difficile is an anaerobic, spore-forming bacterium that is the most common cause of healthcare-associated diarrhea in developed countries. A significant proportion of patients receiving oral vancomycin or metronidazole for treatment of Clostridium difficile infection (CDI) develop recurrences. However, the period of vulnerability to re-establishment of colonization by C. difficile after therapy is not well defined.

Principal Findings

In a prospective study of CDI patients, we demonstrated that most vancomycin-treated patients maintained inhibitory concentrations of vancomycin in stool for 4 to 5 days after therapy, whereas metronidazole was only detectable during therapy. From the time of elimination of the antibiotics to 14 to 21 days after therapy, a majority of stool suspensions supported growth of C. difficile and deep 16S rRNA sequencing demonstrated persistent marked alteration of the indigenous microbiota. By 21 to 28 days after completion of CDI treatment, a majority of stool suspensions inhibited growth of C. difficile and there was evidence of some recovery of the microbiota.

Conclusions

These data demonstrate that there is a vulnerable period for re-establishment of C. difficile colonization after CDI treatment that begins within a few days after discontinuation of treatment and extends for about 3 weeks in most patients.     

Golgi Enrichment and Proteomic Analysis of Developing Pinus radiata Xylem by Free-Flow Electrophoresis

Our understanding of the contribution of Golgi proteins to cell wall and wood formation in any woody plant species is limited. Currently, little Golgi proteomics data exists for wood-forming tissues. In this study, we attempted to address this issue by generating and analyzing Golgi-enriched membrane preparations from developing xylem of compression wood from the conifer Pinus radiata. Developing xylem samples from 3-year-old pine trees were harvested for this purpose at a time of active growth and subjected to a combination of density centrifugation followed by free flow electrophoresis, a surface charge separation technique used in the enrichment of Golgi membranes. This combination of techniques was successful in achieving an approximately 200-fold increase in the activity of the Golgi marker galactan synthase and represents a significant improvement for proteomic analyses of the Golgi from conifers. A total of thirty known Golgi proteins were identified by mass spectrometry including glycosyltransferases from gene families involved in glucomannan and glucuronoxylan biosynthesis. The free flow electrophoresis fractions of enriched Golgi were highly abundant in structural proteins (actin and tubulin) indicating a role for the cytoskeleton during compression wood formation. The mass spectrometry proteomics data associated with this study have been deposited to the ProteomeXchange with identifier PXD000557.     

Reproductive success of Woodlarks Lullula arborea in traditional and recently colonized habitats

Capsule Set-aside schemes have allowed breeding Woodlarks to colonize farmland, but heathland and forestry habitats remain the stronghold.

Aims To determine which habitats provide the best conditions for breeding Woodlarks and whether a buffer effect is operating, with density increasing faster in the poorer quality habitat as the population grows.

Methods Habitat colonization was examined and breeding success compared among heathland, clear-felled and young conifer plantations, and farmland set-aside.

Results Woodlarks on heathland and forestry habitats had similar clutch sizes and nesting success, but clutch sizes may be lower on farmland. Heathland was recolonized when population density was low in forest habitats, while farmland was colonized when density was increasing, and areas close to forest were preferentially occupied. Woodlarks breeding on farmland preferred set-aside stubbles to other field types.

Conclusion Forestry and heathland habitats are similar in quality for breeding Woodlarks, with no evidence for a buffer effect. Farmland set-aside may be suboptimal but the area available is much greater than the area of forest or heathland, and could therefore make a significant contribution to the conservation of the Woodlark population. However, set-aside should not be seen as an alternative to the conservation of forest and heathland.     

Cysteine Scanning Mutagenesis of Transmembrane Helix 3 of a Brain Glutamate Transporter Reveals Two Conformationally Sensitive Positions

Glutamate transporters in the brain remove the neurotransmitter from the synapse by cotransport with three sodium ions into the surrounding cells. Recent structural work on an archaeal homolog suggests that, during substrate translocation, the transport domain, including the peripheral transmembrane helix 3 (TM3), moves relative to the trimerization domain in an elevator-like process. Moreover, two TM3 residues have been proposed to form part of a transient Na3′ site, and another, Tyr-124, appears close to both Na3′ and Na1. To obtain independent evidence for the role of TM3 in glutamate transport, each of its 31 amino acid residues from the glial GLT-1 transporter was individually mutated to cysteine. Except for six mutants, substantial transport activity was detected. Aqueous accessibility of the introduced cysteines was probed with membrane-permeant and membrane-impermeant sulfhydryl reagents under a variety of conditions. Transport of six single cysteine mutants, all located on the intracellular side of TM3, was affected by membrane-permeant sulfhydryl reagents. However, only at two positions could ligands modulate the reactivity. A120C reactivity was diminished under conditions expected to favor the outward-facing conformation of the transporter. Sulfhydryl modification of Y124C by 2-aminoethyl methanethiosulfonate, but not by N-ethylmaleimide, was fully protected in the presence of sodium. Our data are consistent with the idea that TM3 moves during transport. Moreover, computational modeling indicated that electrostatic repulsion between the positive charge introduced at position 124 and the sodium ions bound at Na3′ and Na1 underlies the protection by sodium.     

Mutations in B3GALNT2 Cause Congenital Muscular Dystrophy and Hypoglycosylation of α-Dystroglycan

Mutations in several known or putative glycosyltransferases cause glycosylation defects in α-dystroglycan (α-DG), an integral component of the dystrophin glycoprotein complex. The hypoglycosylation reduces the ability of α-DG to bind laminin and other extracellular matrix ligands and is responsible for the pathogenesis of an inherited subset of muscular dystrophies known as the dystroglycanopathies. By exome and Sanger sequencing we identified two individuals affected by a dystroglycanopathy with mutations in β-1,3-N-acetylgalactosaminyltransferase 2 (B3GALNT2). B3GALNT2 transfers N-acetyl galactosamine (GalNAc) in a β-1,3 linkage to N-acetyl glucosamine (GlcNAc). A subsequent study of a separate cohort of individuals identified recessive mutations in four additional cases that were all affected by dystroglycanopathy with structural brain involvement. We show that functional dystroglycan glycosylation was reduced in the fibroblasts and muscle (when available) of these individuals via flow cytometry, immunoblotting, and immunocytochemistry. B3GALNT2 localized to the endoplasmic reticulum, and this localization was perturbed by some of the missense mutations identified. Moreover, knockdown of b3galnt2 in zebrafish recapitulated the human congenital muscular dystrophy phenotype with reduced motility, brain abnormalities, and disordered muscle fibers with evidence of damage to both the myosepta and the sarcolemma. Functional dystroglycan glycosylation was also reduced in the b3galnt2 knockdown zebrafish embryos. Together these results demonstrate a role for B3GALNT2 in the glycosylation of α-DG and show that B3GALNT2 mutations can cause dystroglycanopathy with muscle and brain involvement.     

Mobility histories of 7th–9th century AD people buried at early medieval Bamburgh,Northumberland, England

Early Medieval England is described historically as a time when people migrated from the Continent to English shores. This study tests the hypothesis that those buried in the Bowl Hole cemetery, Bamburgh, Northumberland were nonlocally born, because of its royal status. Ninety‐one male and female adult, and nonadult, skeletons were studied. Isotope ratios of strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (δ¹⁸O) were generated for 78 individuals (28 females, 27 males, five “adults,” 18 nonadults). The mean Sr value for human enamel was 0.71044, standard deviation (sd) 0.001, and the mean O (δw) value is ?5.9‰, sd 1.6‰. Additionally, animal tooth enamel (mean Sr value 0.710587, sd 0.001; mean O value ?6.5‰, sd 1.5‰), local soil (mean Sr value 0.709184, sd 0.0006), snail shells (mean Sr value 0.708888, sd 0.0001), and soil samples from a 5 km transect heading inland (mean Sr value 0.709121, sd 0.0003), were analyzed for an indication of the isotopic composition of bioavailable Sr in the modern environment and to assess the impact of sea‐spray; water samples from a well, local rivers, and standing water were analyzed for local δ¹⁸O values (mean O value ?6.4‰, relative to VSMOW, sd 2.8‰). Over 50% of those buried at Bamburgh were nonlocal. All ages and both sexes produced “nonlocal” signatures; some suggested childhood origins in Scandinavia, the southern Mediterranean or North Africa. Stature and other indicators of health status indicated differences in quality of life between local and migrant groups. These differences did not extend to burial practices. Am J Phys Anthropol 151:462–476, 2013.© 2013 Wiley Periodicals, Inc.     

High-density genetic maps for loci involved in nuclear male sterility (NMS1) and sporophytic self-incompatibility (S-locus) in chicory (Cichorium intybus L., Asteraceae)

High-density genetic maps were constructed for loci involved in nuclear male sterility (NMS1-locus) and sporophytic self-incompatibility (S-locus) in chicory (Cichorium intybus L.). The mapping population consisted of 389 F1′ individuals derived from a cross between two plants, K28 (male-sterile) and K59 (pollen-fertile), both heterozygous at the S-locus. This F1′ mapping population segregated for both male sterility (MS) and strong self-incompatibility (SI) phenotypes. Phenotyping F1′ individuals for MS allowed us to map the NMS1-locus to linkage group (LG) 5, while controlled diallel and factorial crosses to identify compatible/incompatible phenotypes mapped the S-locus to LG2. To increase the density of markers around these loci, bulked segregant analysis was used. Bulks and parental plants K28 and K59 were screened using amplified fragment length polymorphism (AFLP) analysis, with a complete set of 256 primer combinations of EcoRI-ANN and MseI-CNN. A total of 31,000 fragments were generated, of which 2,350 showed polymorphism between K59 and K28. Thirteen AFLP markers were identified close to the NMS1-locus and six in the vicinity of the S-locus. From these AFLP markers, eight were transformed into sequence-characterized amplified region (SCAR) markers and of these five showed co-dominant polymorphism. The chromosomal regions containing the NMS1-locus and the S-locus were each confined to a region of 0.8 cM. In addition, we mapped genes encoding proteins similar to S-receptor kinase, the female determinant of sporophytic SI in the Brasicaceae, and also markers in the vicinity of the putative S-locus of sunflower, but none of these genes or markers mapped close to the chicory S-locus.