Novel primers for detection and quantification of Myxococcus species in situ

A nested polymerase chain reaction (PCR) protocol using unique primers was developed to detect and quantify Myxococcus species from environmental samples. The protocol amplified most species of Myxococcus when 10 pg of DNA representing 1000 cells was present, although over half were amplified with as little as 0.1 pg (10 cells). The protocol did not amplify other myxobacterial species, members of the δ‐proteobacteria or other unrelated organisms tested at significantly higher concentrations of DNA. The primers were also used in quantitative PCRs, which accurately estimated the population levels in soil.     

Microhabitat selection by two reptile ticks at their parapatric boundary

The parapatric boundary between the reptile ticks. Aponomma hydrosauri and Amblyomma limbatum, near Mt Mary, South Australia, coincides with a vegetational ecotone. Samples of litter from each side of the tick boundary showed considerable heterogeneity, but there were consistent differences in the composition and quantity of litter. North of the boundary, where Amb. limbatum is found, there is less litter and an absence of Eucalyptus leaves in the litter. Since the litter retards evaporative water loss, and Ap. hydrosauri is less tolerant of dehydration, reduced litter quantity may reduce the fitness of colonizing Ap. hydrosauri. In laboratory and field trials, larvae and nymphs of both tick species chose litter microhabitats in preference to bare soil, with the exception of fed Ap. hydrosauri larvae which, in trials with litter from north of the boundary, rarely moved from the bare soil. This behaviour may also reduce the fitness of colonizing Ap. hydrosauri. The two species adopted different positions in the litter. Ap. hydrosauri were predominantly found on the surface, at the interface between soil and litter as fed larvae, and on or under the surface as nymphs. Amb. limbatum larvae were more often buried under the surface, while nymphs were found mostly in the litter above the soil surface. Hypotheses to explain the maintenance of the parapatric boundary are discussed in the light of these results.     

Heterogeneity of resource utilization in a population of the Australian reptile tick, Aponomma hydrosauri (Denny)

Abstract. 1. The distribution of adult males, nymphs and larvae of the reptile tick Aponoma hydrosauri on their host, Trachydosaurus rugosus , in a study area near Tickera, South Australia, did not follow the Poisson distribution predicted if hosts were infested at random.
2. The non-random distribution of males can be accounted for by geographical heterogeneity in distribution. Adult females also showed geographical heterogeneity in their distribution pattern, but infested their hosts at random over all.
3. Larvae and nymphs show distribution patterns which change both with the time and the locality. However, when these biases are removed the distribution of larvae and nymphs on their hosts is still non-random.
4. Larger lizards tend to have larger numbers of ticks, but this cannot alone account for the clumped distribution.
5. A model is proposed relating the tick distribution pattern to the particular problems of a resource which is hard to find, but plentiful once found.     

Roadside connectivity does not increase reptile abundance or richness in a fragmented mallee landscape

The effect of isolation and the importance of dispersal in establishing and maintaining populations in fragments of remnant habitat remain poorly understood. Nevertheless, environmental connectivity is likely to be important for ensuring the long‐term preservation of biodiversity in extensively cleared landscapes. In this study, we compared reptile communities in large conservation parks with those in small woodland remnants 6.5–12 km from the parks, on the Eyre Peninsula, South Australia, Australia. We assessed the impact of fragmentation on the abundance, richness and habitat preferences of reptiles, and examined whether connection to linear roadside vegetation altered reptile communities in small woodland remnants. Of the 31 reptile species, 12 were restricted to conservation parks and six to habitat fragments in farmland. There was a substantial reduction in reptile species richness and abundance in farmland fragments. Direct connection of remnant vegetation to roadside corridors did not affect abundance of common species in the farmland fragments, although species richness was lower in isolated remnants in one of our two study regions. The habitat preference of the scincid lizard Menetia greyii differed between farmland fragments, where they were regularly found on dunes and roadsides, and conservation parks, where they were rare and not detected on dunes. We suggest that habitat fragmentation may have altered interspecific interactions, enabling an expansion of habitat use in the farming landscape. Significantly lower abundance of four common species in farmland settings compared with reserves indicated that existing corridors and small fragments provide inadequate connectivity over larger distances. To counter this effect, large reserves may need to be less than 10 km apart.     

Molecular and morphological evidence for a new grass genus,Dupontiopsis (Poaceae tribe Poeae subtribe Poinae s.l.), endemic to alpine Japan,and implications for the reticulate origin of Dupontia and Arctophila within Poinae s.l.

Phylogenetic analyses within Poaceae tribe Poeae subtribes Puccinellinae (=Coleanthinae), Phleinae, Poinae s.l. (including Alopecurinae), and Miliinae (PPAM clade), revealed that one species formerly placed in Poa represents a new monotypic genus belonging to subtribe Poinae s.l., Dupontiopsis gen. nov., D. hayachinensis comb. nov. (based on Poa hayachinensis), endemic to wet, gravelly, serpentine, alpine habitats in northern Japan. This genus forms a strongly supported clade (DAD) with two circumarctic Poinae genera, Arctophila and Dupontia, in phylogenetic analyses of plastid and nuclear ribosomal DNA sequence data. Both morphology and DNA sequence analyses provide support for D. hayachinensis as a lineage distinct from either Arctophila or Dupontia, with moderate DNA support for a position as sister to these two genera. Dupontiopsis resembles these other monotypic genera in its several-flowered spikelets, lemmas usually 3-nerved, with frequently awned attenuate scarious apices (as in Dupontia) and calluses with a crown of hairs around the base of the lemma, but differs in its keeled lemmas, scabrous palea keels, glumes shorter than the first lemma. Our investigation suggests that the most recent shared ancestor of the DAD clade evolved from a single hybridization event, as a hexaploid, probably in western Beringia. The probable parentage of the ancestor is considered to be within the Poinae–Alopecurinae clade excluding Poa. We provide evidence for possible secondary hybridization and introgression of duodecaploid Dupontia fisheri with Puccinellia. A key to perennial genera of PPAM with hairy calluses, and a supplemental table of morphological characters in the genera accepted in PPAM are provided.     

Site localization of sialyl Lewis(x) antigen on alpha1-acid glycoprotein by high performance liquid chromatography-electrospray mass spectrometry

A simple, fast and sensitive method was developed to verify the presence of the sialyl Lewis(x) antigen on an N-linked glycoprotein. High performance liquid chromatography-electrospray mass spectrometry (HPLC-ESI/MS) was used to identify which of the five N-linked glycosylation sites of human plasma alpha1-acid-glycoprotein (orosomucoid, OMD) contain the sialyl Lewis(x) antigen. OMD was digested with proteolytic enzymes and analyzed by reversed phase chromatography coupled with on-line ESI/MS. A tandem mass spectrometry experiment was designed to detect the presence of the sialyl Lewis(x) antigen based on the observation of an 803 mass to charge ratio ( m/z ) ion produced in the intermediate pressure region of the ESI interface. The ESI/MS signal at m/z 803 is consistent with an oxonium ion for a glycan structure containing NeuAc, Gal, GlcNAc, and Fuc. The identity of the m/z 803 ion was confirmed by ESI/MS/MS analysis of the m/z 803 fragment ion and comparison with a sialyl Lewis(x) standard. The stereochemistry and linkage positions were assigned using previous NMR analysis but could be determined with permethylation analysis if necessary. The analysis of OMD gave a pattern showing signal for the sialyl Lewis(x) antigen coeluting with each of the five N-linked glycopeptides. The ability to monitor sialyl Lewis(x) expression at each of the five sites is of interest in the study of OMD's role in inflammatory diseases.      

Hydraulic properties of layered soils influence survival of Rhodes grass (<Emphasis Type="Italic">Chloris gayana</Emphasis> Kunth.) during water stress

Survival of vegetation on soil-capped mining wastes is often impaired during dry seasons due to the limited amount of water stored in the shallow soil capping. Growth and survival of Rhodes grass (Chloris gayana) during soil drying on various layered capping sequences constructed of combinations of topsoil, subsoil, seawater-neutralised residue sand and low grade bauxite was determined in a glasshouse. The aim was to describe the survival of Rhodes grass in terms of plant and soil water relationships. The soil water characteristic curve and soil texture analysis was a good predictor of plant survival. The combination of soil with a high water holding capacity and low soil water diffusivity (e.g. subsoil with high clay contents) with soil having a high water holding capacity and high diffusivity (e.g. residue sand) gave best survival during drying down (up to 88 days without water), whereas topsoil and low grade bauxite were unsuitable (plants died within 18–39 days). Clayey soil improved plant survival by triggering a water stress response during peak evaporative water demand once residue sand dried down and its diffusivity fell below a critical range. Thus, for revegetation in seasonally dry climates, soil capping should combine one soil with low diffusivity and one or more soils with high total water holding capacity and high diffusivity.