Exploring the Gastrointestinal “Nemabiome”: Deep Amplicon Sequencing to Quantify the Species Composition of Parasitic Nematode Communities

Parasitic helminth infections have a considerable impact on global human health as well as animal welfare and production. Although co-infection with multiple parasite species within a host is common, there is a dearth of tools with which to study the composition of these complex parasite communities. Helminth species vary in their pathogenicity, epidemiology and drug sensitivity and the interactions that occur between co-infecting species and their hosts are poorly understood. We describe the first application of deep amplicon sequencing to study parasitic nematode communities as well as introduce the concept of the gastro-intestinal “nemabiome”. The approach is analogous to 16S rDNA deep sequencing used to explore microbial communities, but utilizes the nematode ITS-2 rDNA locus instead. Gastro-intestinal parasites of cattle were used to develop the concept, as this host has many well-defined gastro-intestinal nematode species that commonly occur as complex co-infections. Further, the availability of pure mono-parasite populations from experimentally infected cattle allowed us to prepare mock parasite communities to determine, and correct for, species representation biases in the sequence data. We demonstrate that, once these biases have been corrected, accurate relative quantitation of gastro-intestinal parasitic nematode communities in cattle fecal samples can be achieved. We have validated the accuracy of the method applied to field-samples by comparing the results of detailed morphological examination of L3 larvae populations with those of the sequencing assay. The results illustrate the insights that can be gained into the species composition of parasite communities, using grazing cattle in the mid-west USA as an example. However, both the technical approach and the concept of the ‘nemabiome’ have a wide range of potential applications in human and veterinary medicine. These include investigations of host-parasite and parasite-parasite interactions during co-infection, parasite epidemiology, parasite ecology and the response of parasite populations to both drug treatments and control programs.     

The Maleny ‘Fire Event’: Rehearsals Toward Neo-liminality

Although the anthropological literature on ritual is extensive, little theoretical attention has been paid to recent attempts to (re)create rituals among mainstream groups in post-industrial, secularised societies. The authors address this issue by examiuning the annual Fire Event, which is constructed as a ritual climax to the Maleny Folk Festival in southern Queensland, Australia. Using the work of Victor Turner and John MacAloon as a point of departure, we argue that at best such celebrations constitute a neo-liminal framework within which participants can achieve a consensus of belief and action. By showing that some Fire Events have been more successful ‘rituals’ than others, we also highlight the factors which tend to impede participation and ‘con-subjectivity’ in such settings. In the process we identify some of the cultural divisions at Maleny, such as those between artists and ‘folk’, feral hippies and ‘hoons’, Aboriginals and Anglos, and begin to reflect on how these may relate to more general patterns of interaction in Australian society at large.     

A comparison of blood gases and acid-base measurements in arterial, arterialized venous, and venous blood during short-term maximal exercise

The purpose of this study was to determine the relationship between blood gases and acid-base measurements in arterial, arterialized venous, and venous blood measured simultaneously during short-term maximal exercise. Ten well-trained male cyclists performed a graded maximal exercise test on a cycle ergometer to determine the power output corresponding to their peak oxygen consumption (test I), and a short-term maximal test on a cycle ergometer at peak power output (test II). During test II arterial, arterialized venous and venous blood were sampled simultaneously for determination of partial pressures of oxygen and carbon dioxide, pH, bicarbonate (HCO3-), base excess (BE), and lactate (La). Samples were taken at rest, the end of 1 min of exercise (1 ME), at the end of exercise (EE), and at 2 min of recovery (REC). During test II, subjects maintained a peak power output of 370.6 (62.1) W [mean (SD)] for 4.5, SD 1.6 min. Except at rest venous and arterialized venous measurements tended to be the same at all sampling intervals, but differed significantly from measurements in arterial blood (P less than 0.05). BE was the only variable that rendered consistently significant correlations between arterial and arterialized venous blood at each sampling interval. The pooled correlation coefficient between arterial and arterialized venous BE was r = 0.83 [regression equation: BEa = (0.84 BEav)-0.51]. Arterial La was significantly higher than venous La at 1 ME (2.8, 0.7 vs 0.8, 0.3 mmol.l-1) and higher than both venous and arterialized venous La at EE.(ABSTRACT TRUNCATED AT 250 WORDS)     

Seismic and auditory tuning curves from bullfrog saccular and amphibian papular axons

We present seismic and auditory frequency tuning curves of individual bullfrog, Rana catesbeiana, saccular and amphibian papilla axons that responded to both seismic and auditory stimuli. In this study we found: 1) most saccular axons respond well to auditory stimuli with moderate signal strength (50-70 dB SPL) as well as to seismic stimuli; 2) most amphibian papilla axons respond well to seismic stimuli as well as to auditory stimuli, and their seismic sensitivities are comparable to those of saccular axons (responding to sinusoidal stimuli with peak accelerations in the range 0.001 to 0.1 cm/S2); 3) the responses to both seismic and auditory stimuli from both saccule and amphibian papilla are tuned, i.e. the strength of the response varies with the frequency of the stimulus; and this tuning is clearly not the result of second order resonance; 4) in individual axons the tuning properties for seismic stimuli often are not the same as those for auditory stimuli, a fact that may provide clues about how the stimulus signal energy is transferred to the hair cells in each case.     

Characterisation of Pseudomonas rhamnolipids

The Gram negative organism, Pseudomonas aeruginosa, is often found in the lungs of patients with cystic fibrosis and other forms of severe bronchiectasis, where it secretes a number of extracellular toxins including the mono- and dirhamnolipids. The principal monorhamnolipid from P. aeruginosa has previously been identified as rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoate (Rh-C10.C10). A number of related mono- and dirhamnolipids have been purified from cultures of a clinical isolate of P. aeruginosa and identified by fast atom bombardment and electron impact mass spectrometry: these contain the 3-hydroxyoctanoyl-3-hydroxydecanoate (C8.C10) and 3-hydroxydecanoyl-3-hydroxydodecanoate (C10.C12) homologues. Structural isomers were also present where the order of the lipid linkage was transposed (Rh-C10.C8 and Rh-C12.C10). Unsaturated mono- and dirhamnolipids containing the 3-hydroxydecanoyl-3-hydroxydodec-5-enoate (C10.C12:1) lipid were also present.     

Getting Bigger,Quicker? Gendered Socioeconomic Trajectories in Body Mass Index across the Adult Lifecourse: A Longitudinal Study of 21,403 Australians

Do socioeconomic inequities in body mass index (BMI) widen across the adult lifecourse? BMI data for 29,104 male and 32,454 female person-years aged 15 years and older (21,403 persons in total) were extracted from the Household, Income and Labour Dynamics in Australia between 2006 and 2012. Multilevel linear regression was used to examine age and gender specific trajectories in BMI by quintiles of neighborhood socioeconomic circumstance. Models were adjusted for probable sources of confounding, including couple status, number of children resident, if somebody in the household had been pregnant in the last 12 months, the highest level of education achieved, the average household gross income, and the percentage of time in the last year spent unemployed. Approximately 9.6% of BMI variation was observed between neighborhoods. High neighborhood disadvantage was associated with 2.09 kg/m² heavier BMI (95%CI 1.82, 2.36). At age 15-24y, socioeconomic inequity in BMI was already evident among men and women especially (22.6 kg/m² among women in the most affluent areas compared with 25.4 kg/m² among the most disadvantaged). Among women only, the socioeconomic gap widened from 2.8 kg/m² at age 15-24y to 3.2 kg/m² by age 35-44y. Geographical factors may contribute to more rapid weight gain among women living in disadvantaged neighborhoods.