US Army basic combat training alters the relationship between body mass index and per cent body fat

INTRODUCTION/BACKGROUND

As a proxy for adiposity, body mass index (BMI) provides a practical public health metric to counter obesity-related disease trends. On an individual basis, BMI cannot distinguish fat and lean components of body composition. Further, the relationship between BMI and body composition may be altered in response to physical training. We investigated this dynamic relationship by examining the effect of US Army basic combat training (BCT) on the association between BMI and per cent body fat (%BF).

METHODS

BMI and %BF were measured at the beginning (week 1) and end (week 9) of BCT in female (n=504) and male (n=965) trainees. Height and weight were obtained for BMI, and body composition was obtained by dual X-ray absorptiometry. Sensitivity and specificity of BMI-based classification were determined at two BMI thresholds (25 kg/m2 and 27.5 kg/m2).

RESULTS

A progressive age-related increase in fat-free mass index (FFMI) was observed, with an inflection point at age 21 years. In soldiers aged 21+, BMI of 25.0 kg/m2 predicted 33% and 29% BF in women and 23% and 20% BF in men and BMI of 27.5 kg/m2 predicted 35% and 31% BF in women and 26% and 22% BF in men, at the start and end of BCT, respectively. Sensitivity and specificity of BMI-based classification of %BF were poor. Soldiers below BMI of 20 kg/m2 had normal instead of markedly reduced %BF, reflecting especially low FFMI.

CONCLUSIONS

BCT alters the BMI-%BF relationship, with lower %BF at a given BMI by the end of BCT compared with the beginning, highlighting the unreliability of BMI to try to estimate body composition. The specific BMI threshold of 25.0 kg/m2, defined as 'overweight', is an out-of-date metric for health and performance outcomes. To the extent that %BF reflects physical readiness, these data provide evidence of a fit and capable military force at BMI greater than 25.0 kg/m2.

Trabecular microstructure is influenced by race and sex in Black and White young adults

Lower fracture rates in Black men and women compared to their White counterparts are incompletely understood. High-resolution imaging specific to trabecular bone may provide insight. Black participants have enhanced trabecular morphology. These differences may contribute to the lower fracture risk in Black versus White individuals.

INTRODUCTION

Lower fracture rates in Black men and women compared to their White counterparts may be explained by favorable bone microstructure in Black individuals. Individual trabecular segmentation (ITS) analysis, which characterizes the alignment and plate- and rod-like nature of trabecular bone using high-resolution peripheral quantitative computed tomography (HR-pQCT), may provide insight into trabecular differences by race/ethnic origin.

PURPOSE

We determined differences in trabecular bone microarchitecture, connectivity, and alignment according to race/ethnic origin and sex in young adults.

METHODS

We analyzed HR-pQCT scans of 184 adult (24.2 ± 3.4 years) women (n = 51 Black, n = 50 White) and men (n = 34 Black, n = 49 White). We used ANCOVA to compare bone outcomes, and adjusted for age, height, and weight.

RESULTS

Overall, the effect of race on bone outcomes did not differ by sex, and the effect of sex on bone outcomes did not differ by race. After adjusting for covariates, Black participants and men of both races had greater trabecular plate volume fraction, plate thickness, plate number density, plate surface area, and greater axial alignment of trabeculae, leading to higher trabecular bone stiffness compared to White participants and women, respectively (p < 0.05 for all).

CONCLUSION

These findings demonstrate that more favorable bone microarchitecture in Black individuals compared to White individuals and in men compared to women is not unique to the cortical bone compartment. Enhanced plate-like morphology and greater trabecular axial alignment, established in young adulthood, may contribute to the improved bone strength and lower fracture risk in Black versus White individuals and in men compared to women.

Size, shape, and identity of surface crystals and their relationship to sensory perception of grittiness in soft smear-ripened cheeses

Soft smear-ripened cheeses undergo extensive surface crystallization and radial demineralization of calcium, magnesium, and phosphorus, which likely contributes to radial softening during ripening. Furthermore, anecdotal evidence suggests that grittiness is a common characteristic of smear-ripened cheeses. The primary aims of the present study were to evaluate the intensity of perceived grittiness while assessing other key sensory attributes in US artisanal and European protected designation of origin smear-ripened cheeses, and to relate perceived grittiness to the size, shape, and identity of crystals present in the cheese surface smears. Fully ripened wheels of 24 different varieties of smear-ripened cheeses, 16 produced in the United States and 8 in the European Union, were obtained from retail sources. A trained sensory panel (n = 12) was employed to evaluate intensity of grittiness. Crystals present in the cheese smears were identified by powder X-ray diffractometry and polarized light microscopy, and further evaluated in polarized light microscopy micrographs by image analysis for size and shape characteristics. Mean sensory scores for the 24 cheeses ranged from no perceived grittiness to easily identifiable grittiness. Surface crystals included ikaite, struvite, calcite, and brushite, and mean crystal length and area ranged among cheeses from 27 to 1,096 μm, and 533 to 213,969 μm², respectively. Panel threshold for grittiness occurred at a mean crystal length of about 66 μm and mean crystal area of about 2,913 μm². Cheeses with mean values at or below these thresholds displayed negligible perceived grittiness. In contrast, for cheeses with mean values above these thresholds, the mean sensory scores for grittiness were highly correlated with mean crystal length and crystal area (r = 0.93 and 0.96, respectively). Results suggest that surface crystals in soft smear-ripened cheeses influence sensory perception of texture in complex ways that likely include radial softening and grittiness development. A better understanding of factors that govern surface crystal formation may lead to improved control over crystallization and more consistent cheese texture.

Characterization and identification of surface crystals on smear-ripened cheese by polarized light microscopy

Surface crystallization and radial demineralization of Ca, P, and Mg occur in smear-ripened cheese. Furthermore, crystals of ikaite, struvite, calcite, and brushite have been identified in cheese smears by powder X-ray diffractometry (PXRD), and ikaite and struvite exist in smears as single crystals. Polarized light microscopy (PLM) is a simple, inexpensive, and well-established method in geology to detect and identify single crystals. However, use of PLM to identify cheese crystals has not been reported previously. The specific objectives of this research were (1) to identify crystals in cheese smears using selected PLM criteria; (2) to compare identification by PLM against PXRD; and (3) to develop and evaluate a novel treatment for smear material to improve crystal analyses by both PLM and PXRD. Duplicate wheels of 4 cheeses produced by different manufacturers were obtained from retail sources. Scrapings of surface smears were prepared and analyzed by PLM and PXRD by previously described methods. Crystals were categorized by PLM based on angle of extinction (AE), birefringence behavior under crossed polarizers and quartz filters, and size and shape (circularity) by image analysis. Crystals observed by PLM fell almost exclusively into 2 readily differentiated groups based on birefringence behavior and estimated angle of extinction. Group 1 (n = 18) were highly birefringent with AE = 88-92°, whereas group 2 (n = 28) had no birefringence with AE = 13-26°. Group 2 crystals were significantly larger and more circular than group 1 crystals. Group 1 and 2 were identified as struvite and ikaite, respectively, based on known birefringence and AE characteristics. Struvite was identified in all 4 cheeses by PLM but in only 3 cheeses by PXRD. Ikaite was identified in 3 cheeses by PLM but in only 2 cheeses by PXRD. These discrepancies occurred because the smear scrapings from 1 cheese contained excessive amorphous matter that caused extreme background noise, potentially obscuring diffractogram peaks that may have been present. To minimize noise, smear scrapings were dispersed in aqueous NaOH (pH 10) before analyses, which resulted in consistent results by PXRD and PLM. The method also rendered high-quality images by PLM. Data suggest that PLM may offer a simple and inexpensive means to identify struvite, ikaite, and possibly other single crystals in cheese smears.

Temporal Changes Rather than Long-Term Repeated Burning Predominately Control the Shift in the Abundance of Soil Denitrifying Community in an Australian Sclerophyll Forest

To understand the temporal dynamics of soil bacterial denitrifying community in response to long-term prescribed burning and its resilience and recovery following a fire, a wet sclerophyll forest study site under two treatments (2 yearly burning (2YB) and no burning (NB)) and with 40-year-old burning history was used. Similar temporal patterns in the abundance of total (16S rRNA) and denitrifying (narG, nirK, nirS, nosZ) bacteria between two burning treatments revealed strong temporal influences. The magnitude of burning impacts on the abundance of 16S rRNA and denitrification genes was smaller compared with the impact of sampling time, but significant burning and temporal impacts were recorded for all (P < 0.001)-except for the nirS gene. Impacts of prescribed fire on the abundance of soil denitrifying community could be observed immediately after fire, and this impact diminished over a 24-month period prior to the next prescribed burning event. In conclusion, temporal changes govern the fluctuations of the abundance of soil denitrifying genes over the sampling period and the denitrifying community can recover after fire, suggesting that this community is resilient to the effects of prescribed burning. A combination of biotic and abiotic factors may account for the different temporal dynamics of denitrification gene abundance.

Crystal fingerprinting: elucidating the crystals of Cheddar, Parmigiano-Reggiano, Gouda, and soft washed-rind cheeses using powder x-ray diffractometry

Crystals in cheese may be considered defects or positive features, depending on the variety and mode of production (industrial, artisanal). Powder x-ray diffractometry (PXRD) offers a simple means to identify and resolve complex combinations of crystals that contribute to cheese characteristics. The objective of the present research was to demonstrate the application of PXRD to study crystals from a range of different cheese types, specifically Cheddar, Parmigiano-Reggiano, Gouda, and soft washed-rind (smear ripened) cheeses. In studies of Parmigiano-Reggiano and long-aged Gouda, PXRD has confirmed that hard (crunchy) crystals that form abundantly within these cheeses consist of tyrosine. Furthermore, PXRD has tentatively identified the presence of an unusual form of crystalline leucine in large (up to 6 mm in diameter) spherical entities, or “pearls”, that occur abundantly in 2-year-old Parmigiano Reggiano and long-aged Gouda cheeses, and on the surface of rindless hard Italian-type cheese. Ongoing investigations into the nature of these “pearls” are providing new insight into the roles that crystals play in the visual appearance and texture of long-aged cheeses. Crystals also sometimes develop profusely in the eyes of long-aged Gouda, which have been shown by PXRD to consist of tyrosine and the aforementioned presumptive form of crystalline leucine. Finally, crystals have been shown by PXRD to form in the smears of soft washed-rind cheeses. These crystals may be associated in some cheeses with gritty mouth feel and with zonal body softening that occurs during ripening. Heightened interest in artisanal cheeses highlights the need to better understand crystals and their contributions to cheese characteristics.

Beef longissimus eating quality increases up to 20 weeks of storage and is unrelated to meat colour at carcass grading

Optimal beef meat colour is associated with increased consumer acceptance, whereas dark or pale meat has a reduced desirability. Dark beef also has a variable eating quality and reduced shelf-life. We hypothesised that a poor meat colour at carcass grading would generate an unacceptable eating quality after vacuum-packed chilled storage for up to 20 weeks, due to the unfavourable pH conditions commonly associated with light and dark muscles. At three beef processing plants, beef longissimus muscles from 81 pasture- and grain-fed cattle (mix of Bos taurus and Bos indicus × Bos taurus) were graded at ~24 h post-slaughter for meat colour. The carcasses were allocated to light, medium and dark colour groups, with n = 27 carcasses per colour group. From the 81 carcasses, a total of 162 longissimus lumborum (LL) muscles was collected and half LLs were randomly allocated to three ageing times (2, 12, 20 weeks) within colour group and six half LLs were used per colour group within storage period and plant. Vacuum-packed muscles were stored at –1.0 ± 0.5°C for the designated period and sampled for biochemical and sensory assessments. The effects of colour group, storage week and carcass traits were analysed. Dark muscles had higher pH than the lighter ones (P < 0.05). The carcass trait dentition, feed type and fat depth did not influence the eating quality (P > 0.05). After 2, 12 and 20 weeks of vacuum-packed chilled storage; eating quality was similar for all 3 meat-colour groups (P > 0.05). With increasing storage time, all eating-quality attributes improved (P < 0.001 for all). Lipid oxidation increased with storage time and although values at 20 weeks were slightly above accepted levels for rancidity detection, MQ4 scores indicated that the meat would still be categorised as a three-star product, indicative of the opportunity to store the longissimus lumborum (LL) for this length of time, while maintaining an acceptable eating quality, regardless of meat colour at carcass grading.

CXCL1 is a negative regulator of mast cell chemotaxis to airway smooth muscle cell products in vitro

BACKGROUND

Activated mast cells (MC) numbers on airway smooth muscle (ASM) are increased in eosinophilic asthma. In vitro, asthmatic cytokine-stimulated ASM cell-conditioned medium (CM) induces more MC chemotaxis than CM from nonasthmatic ASM cells. Intriguingly the nonasthmatic ASM CM inhibits MC chemotaxis to the asthmatic ASM CM. However, the inhibitory factor(s) in the nonasthmatic ASM CM is still to be identified.

OBJECTIVE

To identify the factor(s) released by nonasthmatic ASM cells that inhibits MC chemotaxis.

METHODS

Confluent, serum-starved ASM cells from donors with and without asthma were stimulated with IL-1β and T-helper (Th)1 (TNFα and IFNγ) or Th2 (IL-4, IL-13) cytokines, or left unstimulated. CM samples were collected after 24 h, and a potential inhibitory factor identified using cytokine protein arrays. Its production was assessed using ELISA and RT-PCR and inhibitory role investigated in MC chemotaxis and Ca(2+) mobilization assays.

RESULTS

Only CXCL1 was produced in greater amounts by nonasthmatic than asthmatic ASM cells following Th1 and Th2 cytokine stimulation. CXCL1 mRNA expression was also increased. Exogenous rh-CXCL1 significantly inhibited MC intracellular Ca(2+) mobilization and chemotaxis to either CXCL10, CXCL8 or CM collected from asthmatic ASM cells following Th1 or Th2 cytokine stimulation. Neutralizing CXCL1 in nonasthmatic ASM CM or blocking its receptor significantly promoted MC chemotaxis.

CONCLUSIONS

CXCL1 was a major factor regulating MC chemotaxis in vitro. Its differential release by ASM cells may explain the differences observed in MC localization to the ASM of people with and without asthma.

CLINICAL RELEVANCE

CXCL1 inhibition of MC recruitment to the ASM may lead to new targets to limit asthma pathophysiology.

A structural approach to understanding the interactions between colour, water-holding capacity and tenderness

The colour, water-holding capacity (WHC) and tenderness of meat are primary determinants of visual and sensory appeal. Although there are many factors which influence these quality traits, the end-results of their influence is often through key changes to the structure of muscle proteins and their spatial arrangement. Water acts as a plasticiser of muscle proteins and water is lost from the myofibrillar lattice structure as a result of protein denaturation and consequent reductions in the muscle fibre volume with increasing cooking temperature. Changes in the myofilament lattice arrangement also impact the light scattering properties and the perceived paleness of the meat. Causes of variation in the quality traits of raw meat do not generally correspond to variations in cooked meat and the differences observed between the raw muscle and cooked or further processed meat are discussed. The review will also identify the gaps in our knowledge and where further investigation would beneficial.

Improving beef meat colour scores at carcass grading

Unacceptable meat colour scores at the time of carcass grading are associated with reduced meat quality and consumer rejection. We hypothesised that the meat colour at carcass grading would be influenced by the pH and temperature decline post slaughter, as these would be determined by animal and processing factors. Beef carcasses (n = 1512) at seven Australian processing plants were assessed, at grading, for the meat colour of the M. longissimus thoracis. Statistical modelling determined the animal, carcass and processing factors contributing to the meat colour score at carcass grading. The occurrence of unacceptably dark meat dropped from 8 to 3% when the time of grading was increased from 14 to 31 h post slaughter (P < 0.01). A high temperature at pH 6 (rigor temperature), high final pH (pHF), pasture feeding and older animals were associated with dark M. longissimus thoracis at carcass grading (P < 0.05 for all). Less than 30% of carcasses with non-compliant pHF displayed a dark non-compliant meat colour >3, indicative of an opportunity to determine the mechanism behind this pH-induced colour development and thus reduce the incidence of non-compliance. It is recommended that when there is a high occurrence of carcasses with a dark meat colour >3 that the time from slaughter to grading is checked to ensure carcasses are in full rigor at the grading point. This will assist in minimising economic penalties due to dark-coloured carcasses. Finally, animal factors, such as maturity and feeding regime also had a considerable impact on the meat colour at carcass grading.

The O-linked glycans of human von Willebrand factor modulate its interaction with ADAMTS-13

BACKGROUND

O-linked glycans (OLGs) are clustered on either side of the von Willebrand factor (VWF) A1 domain and modulate its interaction with platelets; however, their influence on the VWF interaction with ADAMTS-13 is unknown.

OBJECTIVES

To assess the role of the OLGs in VWF susceptibility to ADAMTS-13 proteolysis, which would help to explain their specific distribution.

METHODS

OLG sites were mutated individually and as clusters on either and both sides of the A1 domain, and expressed in HEK293T cells. First, their proteolysis by ADAMTS-13 was assayed in the presence of urea. Next, a parallel-flow chamber was used to analyze VWF-mediated platelet capture on collagen in the presence and absence of ADAMTS-13 under a shear stress of 1500 s(-1) . The decrease in platelet capture in the presence ADAMTS-13 was used as a measure of VWF proteolysis.

RESULTS

Initially, we found that, under denaturing conditions, the C-terminal S1486A and Cluster 2 and double cluster (DC) variants were less susceptible to ADAMTS-13 proteolysis than wild-type VWF. Next, we showed that addition of ADAMTS-13 diminished VWF-mediated platelet capture on collagen under flow; surprisingly, this was more pronounced with the S1486A, Cluster 2 and DC variants than with wild-type VWF, indicating that these are proteolyzed more rapidly under shear flow.

CONCLUSIONS

OLGs provide rigidity to peptide backbones, and our findings suggest that OLG in the A1-A2 linker region regulates VWF conformational changes under shear. Importantly, the impact of OLGs on ADAMTS-13 cleavage under shear stress is the opposite of that under denaturing conditions, highlighting the non-physiologic nature of in vitro cleavage assays.

Airway smooth muscle CXCR3 ligand production: regulation by JAK-STAT1 and intracellular Ca²⁺

In asthma, airway smooth muscle (ASM) chemokine (C-X-C motif) receptor 3 (CXCR3) ligand production may attract mast cells or T lymphocytes to the ASM, where they can modulate ASM functions. In ASM cells (ASMCs) from people with or without asthma, we aimed to investigate JAK-STAT1, JNK, and Ca²⁺ involvement in chemokine (C-X-C motif) ligand (CXCL)10 and CXCL11 production stimulated by interferon-γ, IL-1β, and TNF-α combined (cytomix). Confluent, growth-arrested ASMC were treated with inhibitors for pan-JAK (pyridone-6), JAK2 (AG-490), JNK (SP-600125), or the sarco(endo)plasmic reticulum Ca²⁺ATPase (SERCA) pump (thapsigargin), Ca²⁺ chelator (BAPTA-AM), or vehicle before and during cytomix stimulation for up to 24 h. Signaling protein activation as well as CXCL10/CXCL11 mRNA and protein production were examined using immunoblot analysis, real-time PCR, and ELISA, respectively. Cytomix-induced STAT1 activation was lower and CXCR3 ligand mRNA production was more sensitive to pyridone-6 and AG-490 in asthmatic than nonasthmatic ASMCs, but CXCL10/CXCL11 release was inhibited by the same proportion. Neither agent caused additional inhibition of release when used in combination with the JNK inhibitor SP-600125. Conversely, p65 NF-κB activation was higher in asthmatic than nonasthmatic ASMCs. BAPTA-AM abolished early CXCL10/CXCL11 mRNA production, whereas thapsigargin reduced it in asthmatic cells and inhibited CXCL10/CXCL11 release by both ASMC types. Despite these inhibitory effects, neither Ca²⁺ agent affected early activation of STAT1, JNK, or p65 NF-κB. In conclusion, intracellular Ca²⁺ regulated CXCL10/CXCL11 production but not early activation of the signaling molecules involved. In asthma, reduced ASM STAT1-JNK activation, increased NF-κB activation, and altered Ca²⁺ handling may contribute to rapid CXCR3 ligand production and enhanced inflammatory cell recruitment.

Development of a scalable image formation pipeline for multiscale gigapixel photography

We report on the image formation pipeline developed to efficiently form gigapixel-scale imagery generated by the AWARE-2 multiscale camera. The AWARE-2 camera consists of 98 "microcameras" imaging through a shared spherical objective, covering a 120° x 50° field of view with approximately 40 microradian instantaneous field of view (the angular extent of a pixel). The pipeline is scalable, capable of producing imagery ranging in scope from "live" one megapixel views to full resolution gigapixel images. Architectural choices that enable trivially parallelizable algorithms for rapid image formation and on-the-fly microcamera alignment compensation are discussed.

Evidence for multiple historical colonizations of an endoreic drainage basin by an Australian freshwater fish

The contemporary and historical colonization capacity of an Australian freshwater fish, north-west glassfish Ambassis sp., was tested using mtDNA sequence data and six newly developed microsatellite loci in an endoreic basin in central Australia. Overall, Ambassis sp. exhibited weak genetic structure within catchments, suggesting some capacity to recolonize extirpated waterholes after disturbance. Genetic structure revealed that the historical pattern of connectivity among catchments in the Lake Eyre Basin was dramatically different from other species studied in this region. Two highly divergent clades were detected in separate catchments in the basin. mtDNA from individuals sampled in catchments north of the Lake Eyre Basin suggest that Ambassis sp. has colonized on two separate occasions from catchments in northern Australia, subsequently generating two highly divergent lineages.

Human lung mast cells modulate the functions of airway smooth muscle cells in asthma

BACKGROUND

Activated mast cell densities are increased on the airway smooth muscle in asthma where they may modulate muscle functions and thus contribute to airway inflammation, remodelling and airflow obstruction.

OBJECTIVES

To determine the effects of human lung mast cells on the secretory and proliferative functions of airway smooth muscle cells from donors with and without asthma.

METHODS

Freshly isolated human lung mast cells were stimulated with IgE/anti-IgE. Culture supernatants were collected after 2 and 24 h and the mast cells lysed. The supernatants/lysates were added to serum-deprived, subconfluent airway smooth muscle cells for up to 48 h. Released chemokines and extracellular matrix were measured by ELISA, proliferation was quantified by [(3) H]-thymidine incorporation and cell counting, and intracellular signalling by phospho-arrays.

RESULTS

Mast cell 2-h supernatants reduced CCL11 and increased CXCL8 and fibronectin production from both asthmatic and nonasthmatic muscle cells. Leupeptin reversed these effects. Mast cell 24-h supernatants and lysates reduced CCL11 release from both muscle cell types but increased CXCL8 release by nonasthmatic cells. The 24-h supernatants also reduced asthmatic, but not nonasthmatic, muscle cell DNA synthesis and asthmatic cell numbers over 5 days through inhibiting extracellular signal-regulated kinase (ERK) and phosphatidylinositol (PI3)-kinase pathways. However, prostaglandins, thromboxanes, IL-4 and IL-13 were not involved in reducing the proliferation.

CONCLUSIONS

Mast cell proteases and newly synthesized products differentially modulated the secretory and proliferative functions of airway smooth muscle cells from donors with and without asthma. Thus, mast cells may modulate their own recruitment and airway smooth muscle functions locally in asthma.

Failure of orally administered zinc to prevent experimentally induced footrot in sheep

Two groups of adult Merino sheep, initially grazed on pasture, were dosed daily with zinc sulphate (1 mg Zn/kg LW) or zinc oxide (15 mg Zn/kg LW) for six and seven weeks, respectively. On the 18th day, both groups were transferred to indoor pens together with unmedicated control sheep, and five days later the feet of all animals were infected artificially with a virulent strain of Bacteroides nodosus. By the fourth week after challenge, 85% or more of the feet challenged had developed advanced footrot, and no significant differences in the incidence and severity of lesions between dosed and un-dosed groups were recorded. Plasma zinc concentrations, monitored throughout the experiment, remained at similar levels in sheep receiving the lower dose rate and in the controls. At the higher dose rate, plasma zinc levels increased till Day 23, but thereafter declined to values comparable to those of undosed animals. At post mortem, no evidence of zinc toxicosis was found, and only the kidneys of sheep receiving the higher dosage showed a significant accumulation of zinc compared with the controls.

Comparison of footbathing treatments for ovine footrot using formalin or zinc sulphate

A field trial was carried out to compare 3 topical treatments for ovine footrot. They were preliminary hoof paring with weekly footbathing either in 10% formalin, or in 10% zinc sulphate + 0.2% anionic surfactant ('Teepol'), or twice-weekly footbathing in the same zinc sulphate-surfactant mixture without hoof paring. Control sheep were not treated. Within 21 days, the number and severity of active lesions of footscald and footrot among treated sheep were substantially reduced by comparison with the controls; no significant differences were observed between treatments. Treatment effects were also comparable against mild footrot infection of the sole or heel region, hut in the more advanced lesions the healing response to paring and zinc footbathing was superior to that from paring and formalin footbathing (P<0.01). Twice-weekly footbathing in zinc-surfactant solution was effective in preventing new footrot infection. No chronic toxic effects attributable to zinc sulphate at a concentration of 10% were demonstrable in the hoof integument either clinically or histologically.

Genetic analysis of threatened Australian grayling Prototroctes maraena suggests recruitment to coastal rivers from an unstructured marine larval source population

Population genetic variation of Australian grayling Prototroctes maraena was examined to determine whether the dispersal strategy of this amphidromous species favours retention of larvae and juveniles in close proximity to their natal river, or mixing of populations via marine dispersal. Variation in microsatellite and mitochondrial DNA markers was unstructured and differentiation was indistinguishable from zero across four coastal rivers spanning approximately one-quarter of the continental range of the species. This result indicates that the marine larval and juvenile phase probably facilitates extensive gene flow among coastal rivers and agrees with a previous analysis of otolith chemistry that suggested larvae probably move into the sea rather than remain in estuaries. It appears likely that the dispersal strategy of P. maraena would enable recolonization of rivers that experience localized extinction provided that connectivity between freshwater habitats and the sea is sufficient to permit migration and that enough source populations remain intact to support viability of the wider population.

Genetic structure and phylogeography of two freshwater fishes, Rhadinocentrus ornatus and Hypseleotris compressa, in southern Queensland, Australia, inferred from allozymes and mitochondrial DNA

This study used allozyme and mtDNA variation to examine genetic structure in Rhadinocentrus ornatus and Hypseleotris compressa in southern Queensland. The aim of this study was to test the hypothesis that dispersal between coastal streams was greater in R. ornatus than in H. compressa and to test whether R. ornatus would reflect a similar pattern seen in another obligate freshwater fish in the same region, that is, R. ornatus will show genetic homogeneity among streams of the Sunshine Coast but significant differentiation among all other streams. Evidence from the current study suggests that, in R. ornatus, there was significant genetic differentiation among populations within regions, which explains why this species has very restricted dispersal abilities between streams, even between those very close to one another. On the other hand, H. compressa showed very low levels of genetic differentiation suggesting some gene flow among regions by virtue of dispersal. High levels of genetic differentiation were identified between all coastal streams in the area, including those hypothesized to have been recently connected in the Sunshine Coast area in the case of R. ornatus.

Comparing the performance of multiple mitochondrial genes in the analysis of Australian freshwater fishes

In this study, four mitochondrial genes (cytochrome oxidase I, ATPase, cytochrome b and control region) were amplified from most of the fish species found in the fresh waters of south-eastern Queensland, Australia. The performance of these different gene regions was compared in terms of their ability to cluster fish families together in a neighbour-joining tree, both individually by gene and in all combinations. The relative divergence rates of each of these genes were also calculated. The three coding genes (cytochrome oxidase I, ATPase and cytochrome b) recovered similar number of families and had broadly similar divergence rates. ATPase diverged a little more quickly than cytochrome oxidase I and cytochrome b slightly more slowly than cytochrome oxidase I. All two-gene combinations recovered the same number of families. Results from the control region were much more variable, and, although generally possessing more diversity than the other regions, were sometimes less variable.

Multilocus analysis of honeyeaters (Aves: Meliphagidae) highlights spatio-temporal heterogeneity in the influence of biogeographic barriers in the Australian monsoonal zone

Multilocus studies in phylogenetics and comparative phylogeography have the power to explore a broader spectrum of evolutionary questions than either discipline has alone. To examine the origins of sympatry in a group of closely related birds of mostly mesic eucalypt woodlands in Australia, we reconstructed the relationships among species of Entomyzon and Melithreptus honeyeaters (Aves: Passeriformes: Meliphagidae) using a mitochondrial marker, ND2, and six non-coding nuclear loci (total 4719 base pairs). By sampling across the geographical range of each species, we studied not only their phylogenetic relationships to each other but also the spatial distribution of their genetic diversity. We tested several biogeographic hypotheses concerning the role of Pleistocene environmental change in Australia. Phylogenetic gene trees support the current understanding of E. cyanotis as the sister to Melithreptus. Non-monophyly of M. lunatus in Australia's southern temperate woodlands highlights the need for a revision of systematics within Melithreptus. Phylogeographic analysis of the three northern species in Australia's monsoon tropics, M. gularis, M. albogularis and E. cyanotis, suggests that the roles of the Carpentarian and Torresian Barriers in shaping geographic structure in each of the species have been more complex and temporally dynamic than earlier morphology-based arguments of vicariance had suggested. We discuss their roles as ecological filters as well as barriers.

Biological underpinnings of Frost's mechanostat thresholds: the important role of osteocytes

Harold Frost first proposed the existence of several mechanical thresholds in bone, two of which determine whether bone is added to, or lost from, the skeleton. Recent evidence from bone biology helps elucidate the role of osteocytes in determining these mechanical thresholds. Specifically, when mechanical stimuli fall below the resorption threshold, osteocyte apoptosis occurs, followed by bone resorption. Conversely, mechanical loading maintains osteocytes viability, and consequently, no bone is lost. With a greater than customary mechanical stimulus, osteocytes perturbation from pulsatile fluid flow results in release of anabolic factors and subsequent bone formation. Osteocytes also play a pivotal role in bone remodeling in response to alterations in the mechanical environment. In particular, osteocyte apoptosis results in bone turnover in disuse as well as in response to greater than customary mechanical stimuli due to microdamage accumulation. Given the important role of osteocytes in bone modeling and remodeling, these cells provide an ideal target for both drug therapies and exercise to prevent bone fragility.

Alimentary tract bacteria isolated and identified with API-20E and molecular cloning techniques from Australian tropical fruit flies, Bactrocera cacuminata and B. tryoni

Bacteria were isolated from the crop and midgut of field collected Bactrocera cacuminata (Hering) and Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). Two methods were used, firstly isolation onto two types of bacteriological culture media (PYEA and TSA) and identification using the API-20E diagnostic kit, and secondly, analysis of samples using the 16S rRNA gene molecular diagnostic method. Using the API-20E method, 10 genera and 17 species of bacteria in the family Enterobacteriaceae were identified from cultures growing on the nutrient agar. The dominant species in both the crop and midgut were Citrobacter freundii, Enterobacter cloacae and Klebsiella oxytoca. Providencia rettgeri, Klebsiella pneumoniae ssp ozaenae and Serratia marcescens were isolated from B. tryoni only. Using the molecular cloning technique that is based on 16S rRNA gene sequences, five bacteria classes were dignosed — Alpha-, Beta-, Gamma- and Delta- Proteobacteria and Firmicutes — including five families, Leuconostocaceae, Enterococcaceae, Acetobacteriaceae, Comamonadaceae and Enterobacteriaceae. The bacteria affiliated with Firmicutes were found mainly in the crop while the Gammaproteobacteria, especially the family Enterobacteriaceae, was dominant in the midgut. This paper presents results from the first known application of molecular cloning techniques to study bacteria within tephritid species and the first record of Firmicutes bacteria in these flies.

CD40 and OX40 ligand are differentially regulated on asthmatic airway smooth muscle

BACKGROUND

CD40 and OX40 Ligand (OX40L) are cell-surface molecules expressed on airway smooth muscle (ASM) that can enhance inflammatory cell activation and survival. The aim of this study was to examine the effect of tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) on ASM CD40 and OX40L expression.

METHODS

CD40 and OX40L expression on human ASM cells from asthmatic and nonasthmatic donors following stimulation with TNF-alpha and/or IFN-gamma was measured using cell-surface enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Involvement of signalling pathway was investigated with pharmacological inhibitors. Soluble TNF receptor levels were quantified by ELISA.

RESULTS

Interferon-gamma and TNF-alpha synergistically increased CD40 expression to a greater extent on asthmatic than on nonasthmatic ASM. In contrast, IFN-gamma reduced TNF-alpha-induced OX40L expression to a similar extent in both cell types. TNF-alpha and IFN-gamma induced CD40 via nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription-3 in both cell types and modulated OX40L via NF-kappaB and c-Jun N terminal kinase in nonasthmatic cells. Similar effects on the induction of OX40L in asthmatic cells were seen with NF-kappaB, but these were not statistically significant. The reduced OX40L expression with TNF-alpha and IFN-gamma involved extracellular regulated kinase 1/2 activation.

CONCLUSION

Asthmatic ASM may modulate airway inflammation locally by increasing CD40 and OX40L expression in response to cytokines. IFN-gamma may regulate ASM pro-inflammatory actions by differentially modulating ASM CD40 and OX40L expression.

Dimethylfumarate inhibits NF-{kappa}B function at multiple levels to limit airway smooth muscle cell cytokine secretion

The antipsoriatic dimethylfumarate (DMF) has been anecdotically reported to reduce asthma symptoms and to improve quality of life of asthma patients. DMF decreases the expression of proinflammatory mediators by inhibiting the transcription factor NF-kappaB and might therefore be of interest for the therapy of inflammatory lung diseases. In this study, we determined the effect of DMF on platelet-derived growth factor (PDGF)-BB- and TNFalpha-induced asthma-relevant cytokines and NF-kappaB activation by primary human asthmatic and nonasthmatic airway smooth muscle cells (ASMC). Confluent nonasthmatic and asthmatic ASMC were incubated with DMF (0.1-100 microM) and/or dexamethasone (0.0001-0.1 microM), NF-kappaB p65 siRNA (100 nM), the NF-kappaB inhibitor helenalin (1 microM) before stimulation with PDGF-BB or TNFalpha (10 ng/ml). Cytokine release was measured by ELISA. NF-kappaB, mitogen and stress-activated kinase (MSK-1), and CREB activation was determined by immunoblotting and EMSA. TNFalpha-induced eotaxin, RANTES, and IL-6 as well as PDGF-BB-induced IL-6 expression was inhibited by DMF and by dexamethasone from asthmatic and nonasthmatic ASMC, but the combination of both drugs showed no glucocorticoid sparing effect in either of the two groups. NF-kappaB p65 siRNA and/or the NF-kappaB inhibitor helenalin reduced PDGF-BB- and TNFalpha-induced cytokine expression, suggesting the involvement of NF-kappaB signaling. DMF inhibited TNFalpha-induced NF-kappaB p65 phosphorylation, NF-kappaB nuclear entry, and NF-kappaB-DNA complex formation, whereas PDGF-BB appeared not to activate NF-kappaB within 60 min. Both stimuli induced the phosphorylation of MSK-1, NF-kappaB p65 at Ser276, and CREB, and all were inhibited by DMF. These data suggest that DMF downregulates cytokine secretion not only by inhibiting NF-kappaB but a wider range of NF-kappaB-linked signaling proteins, which may explain its potential beneficial effect in asthma.

Ethnic differences in bone geometry and strength are apparent in childhood

PURPOSE

Ethnic differences in bone strength and structure likely contribute to the disparity in fracture rates, however few studies have assessed bone structure in multiethnic cohorts of children. The purpose of this study was to investigate ethnic differences in bone strength in childhood and to characterize the structural bases for these differences.

METHODS

Peripheral quantitative computed tomography (pQCT 3000, Orthometrix) was used to assess bone parameters at the radius and tibia in Caucasian (CA, n=21), African American (AA, n=23), and Hispanic (HI, n=29) children (10.9+/-0.1 yrs). At the distal site (8%), we measured compressive bone strength (BSI), trabecular and total bone density, and total bone area. Polar strength-strain index, total and cortical bone area, and cortical density were assessed at the midshaft (50%). Muscle cross-sectional area (CSA) and fat CSA were measured at the tibia (66%) and the radius (50%). Physical activity and calcium intake were assessed by questionnaire. Analysis of covariance was used to compare bone outcomes among ethnic groups adjusting for age, sex, limb length and muscle CSA.

RESULTS

Age, BMI, and body composition were similar among the 3 groups, however AA children were taller and had longer bone length. At all sites, AA and HI children had higher bone strength (SSIp and BSI +10-37%) than CA children due mainly to greater bone tissue density (2-18%>CA) at the distal sites of the radius and tibia. The greater bone strength at the midshaft was due to both a higher bone density (2-5%) and greater bone area than CA (7-18%).

CONCLUSION

AA and HI children have significantly higher bone strength than CA children, due to greater bone volumetric density and greater cortical area. AA and HI children also have higher bone strength relative to load. These observations suggest that ethnic differences in bone strength manifest in childhood.

Does vertical transmission contribute to the prevalence of toxoplasmosis?

Toxoplasma gondii is a ubiquitous parasite with a widespread distribution both in terms of geographical and host range. Although the definitive host is the cat, it is also a major health hazard to domestic animals and humans. Three routes of transmission are recognised (infection from the cat, carnivory and congenital transmission). We aimed to assess the relative importance of congenital transmission, using sheep as a model system, due to the lack of carnivory. We report, using PCR as a diagnostic tool, that congenital transmission occurs with high frequency (69%). If transmission from oocysts was important in sheep, we would expect sheep reared under the same environmental conditions (i.e. a single farm) to have a random distribution of Toxoplasma infection. Using breeding records in conjunction with PCR, some families were found to have high Toxoplasma prevalence and abortion while others were free of Toxoplasma infection and abortion (P < 0.01). This supports the notion that Toxoplasma may be transmitted vertically. In humans, we conducted a similar study and showed that Toxoplasma was transmitted from mother to baby in 19.8% of cases. Vertical transmission in Toxoplasma may be more important than previously thought and this knowledge should be considered in any eradication strategies.

Histamine and tryptase modulate asthmatic airway smooth muscle GM-CSF and RANTES release

Degranulating mast cells are increased in the airway smooth muscle (ASM) of asthmatics, where they may influence ASM function. The aim of the present study was to determine whether histamine and tryptase modulate ASM cell granulocyte-macrophage colony-stimulating factor (GM-CSF) and RANTES (regulated on activation, normal T-cell expressed and secreted) release and also to examine which receptors are involved in this release. Confluent, quiescent ASM cells from asthmatic and nonasthmatic donors were treated with histamine (1 microM-100 microM) with and without histamine receptor antagonist pre-treatment, or the protease-activated receptor (PAR)-2 agonists tryptase (0.5-5 nM) and SLIGKV (100 and 400 microM). The cells were then stimulated with interleukin (IL)-1beta and/or tumour necrosis factor (TNF)-alpha (10 ng.mL(-1)) or left unstimulated for 24 h. Release of GM-CSF and RANTES was determined by ELISA and prostaglandin (PG)E(2) measured by enzyme immunoassay. Neither histamine nor tryptase induced ASM GM-CSF or RANTES secretion. However, histamine increased IL-1beta-induced GM-CSF release and markedly reduced TNF-alpha-induced RANTES release by both asthmatic and nonasthmatic cells to a similar extent, but did not modulate PGE(2) release. All changes involved activation of the histamine H1 receptor as they were partially or fully blocked by chlorpheniramine, but not ranitidine. Tryptase, via its proteolytic activity, also potentiated GM-CSF, but not RANTES, release from asthmatic and nonasthmatic ASM cells induced by both cytokines. PAR-2 involvement in the tryptase potentiation was unlikely because SLIGKV had no effect. In conclusion, mast cells, through histamine and tryptase, may locally modulate airway smooth muscle-induced inflammation in asthma.

Feasibility study of capecitabine (cap) and cisplatin (cis) with radiation therapy (RT) in the management of patients with locally advanced unresectable squamous cell carcinoma of the head and neck (HNSCC)

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Background: Concurrent chemoradiation has become the standard of care for locally advanced unresectable HNSCC. The most commonly used chemotherapy is cis and 5-fluorouracil (5-FU). We evaluated the feasibility of using cap and cis during RT in this population. Cap is an oral pro-drug of 5-FU that can be given daily with RT in order to enhance the activity of RT. Methods: Between Oct, 2003 and Sept, 2005, 12 male patients aged 46–83 were treated at the VA Medical Center. Patients received cis 100 mg/m2 on days 1 and 29 and cap 450 mg/m2 bid (2 hours prior to RT and 12 hours later) for 5 days of each week concurrent with RT to a total dose of 70 Gy in 35 fractions over 7 weeks. Primary endpoint of the study was toxicity. Results: All 12 patients were able to complete therapy. Treatment delays and/or dose modifications were needed in 7 patients. Treatment related toxicities included 6 patients with grade 3 mucositis and 5 patients with grade 3 dysphagia. Other grade 3 toxicities included 3 patients with dehydration and 1 patient each with leucopenia, constipation, nausea and vomiting, and odynophagia. Percutaneous gastrostomy (PEG) tubes were required in 5 patients. Complete response to chemoradiation was seen in 9 patients, 2 patients obtained partial response, and 1 patient progressed. Median progression free and overall survivals have not been reached with a median follow-up of 21 months. Conclusions: Cis and cap administered concurrently with RT has manageable toxicities and is active in patients with locally advanced unresectable HNSCC.

No significant financial relationships to disclose.

Advanced glycation end products cause increased CCN family and extracellular matrix gene expression in the diabetic rodent retina

AIMS/HYPOTHESIS

Referred to as CCN, the family of growth factors consisting of cystein-rich protein 61 (CYR61, also known as CCN1), connective tissue growth factor (CTGF, also known as CCN2), nephroblastoma overexpressed gene (NOV, also known as CCN3) and WNT1-inducible signalling pathway proteins 1, 2 and 3 (WISP1, -2 and -3; also known as CCN4, -5 and -6) affects cellular growth, differentiation, adhesion and locomotion in wound repair, fibrotic disorders, inflammation and angiogenesis. AGEs formed in the diabetic milieu affect the same processes, leading to diabetic complications including diabetic retinopathy. We hypothesised that pathological effects of AGEs in the diabetic retina are a consequence of AGE-induced alterations in CCN family expression.

MATERIALS AND METHODS

CCN gene expression levels were studied at the mRNA and protein level in retinas of control and diabetic rats using real-time quantitative PCR, western blotting and immunohistochemistry at 6 and 12 weeks of streptozotocin-induced diabetes in the presence or absence of aminoguanidine, an AGE inhibitor. In addition, C57BL/6 mice were repeatedly injected with exogenously formed AGE to establish whether AGE modulate retinal CCN growth factors in vivo.

RESULTS

After 6 weeks of diabetes, Cyr61 expression levels were increased more than threefold. At 12 weeks of diabetes, Ctgf expression levels were increased twofold. Treatment with aminoguanidine inhibited Cyr61 and Ctgf expression in diabetic rats, with reductions of 31 and 36%, respectively, compared with untreated animals. Western blotting showed a twofold increase in CTGF production, which was prevented by aminoguanidine treatment. In mice infused with exogenous AGE, Cyr61 expression increased fourfold and Ctgf expression increased twofold in the retina.

CONCLUSIONS/INTERPRETATION

CTGF and CYR61 are downstream effectors of AGE in the diabetic retina, implicating them as possible targets for future intervention strategies against the development of diabetic retinopathy.

Phylogeographic structure in an Australian freshwater shrimp largely pre-dates the geological origins of its landscape

The phylogeographic structure of cryptic lineages within the freshwater shrimp Caridina indistincta Calman, 1926 (Decapoda: Atyidae) was investigated in an attempt to unravel any potential genetic influences of Quaternary sea-level oscillations. The study was based on mitochondrial DNA sequences from specimens from lakes and creeks in the sand dune areas of southeast Queensland, eastern Australia. Four divergent lineages were identified, two of which were from Moreton and North (N.) Stradbroke Islands. Lineage 'C1' has been found only on Moreton Island and the western part of N. Stradbroke Island, whereas 'C2' was found on the eastern side of N. Stradbroke Island and a few locations on the mainland. These diverged from each other during the Late Miocene/Pliocene and so are older than the current landscape in which they are found. Small-scale phylogeographic analysis of C1 identified four separate geographic areas, within the two islands, whose divergences date to the Pleistocene (approximately 100-300 thousand years ago ('kya')). The N. Stradbroke Island population of C2 also diverged from the mainland during the Pleistocene, as did a sympatric freshwater fish Rhadinocentrus ornatus Regan, 1914 (Melanotaeniidae). This implies that the ice-age sea-level changes may have structured these populations, although there is little observable influence of the last glacial maximum (approximately 18 kya). Most estimates for the age of the landscape (dunes, lakes) also fall within the Pleistocene and so the effect of sea-level change may be seen both in biology and geology.

The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations

Neospora caninum and Toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. Little is known about the extent of Neospora/Toxoplasma co-infection in naturally infected populations of animals. Using nested PCR techniques, based on primers from the Nc5 region of N. caninum and SAG1 for T. gondii, the prevalence of N. caninum and its co-infection with T. gondii were investigated in populations of Mus domesticus, Rattus norvegicus and aborted lambs (Ovis aries). A low frequency of infection with N. caninum was detected in the Mus domesticus (3%) and Rattus norvegicus (4.4%) populations. A relatively high frequency of infection with N. caninum was detected in the brains of aborted lambs (18.9%). There was no significant relationship between N. caninum and T. gondii co-infection. Investigation of the tissue distribution of Neospora, in aborted lambs, showed that Neospora could not be detected in tissues other than brain and this was in contrast to Toxoplasma where the parasite could be frequently detected in a range of tissues.

Mast cell migration to Th2 stimulated airway smooth muscle from asthmatics

BACKGROUND

Mast cell microlocalisation within the airway smooth muscle (ASM) bundle is an important determinant of the asthmatic phenotype. We hypothesised that mast cells migrate towards ASM in response to ASM derived chemokines.

METHODS

Primary ASM cultures from subjects with and without asthma were stimulated with interleukin (IL)-1beta, IL-4, and IL-13 alone and in combination. Mast cell chemotaxis towards these ASM supernatants was investigated, and the chemotaxins mediating migration by using specific blocking antibodies for stem cell factor (SCF) and the chemokine receptors CCR3, CXCR1, 3 and 4 as well as the Gi inhibitor pertussis toxin and the tyrosine kinase inhibitor genistein were defined. The concentrations of CCL11, CXCL8, CXCL10, TGF-beta, and SCF in the supernatants were measured and the effect of non-asthmatic ASM supernatants on the mast cell chemotactic activity of asthmatic ASM was examined.

RESULTS

Human lung mast cells and HMC-1 cells migrated towards Th2 stimulated ASM from asthmatics but not non-asthmatics. Mast cell migration was mediated through the combined activation of CCR3 and CXCR1. CCL11 and CXCL8 expression by ASM increased markedly after stimulation, but was similar in those with and without asthma. ASM supernatants from non-asthmatics inhibited mast cell migration towards the asthmatic ASM supernatant.

CONCLUSION

Th2 stimulated ASM from asthmatics is chemotactic for mast cells. Non-asthmatic ASM releases a mediator or mediators that inhibit mast cell migration towards stimulated asthmatic ASM. Specifically targeting mast cell migration into the ASM bundle may provide a novel treatment for asthma.

Biogeographic history of an Australian freshwater shrimp, Paratya australiensis (Atyidae): the role life history transition in phylogeographic diversification

The widespread distribution of the freshwater shrimp Paratya australiensis in eastern Australia suggests that populations of this species have been connected in the past. Amphidromy is ancestral in these shrimps, although many extant populations are known to be restricted to freshwater habitats. In this study, we used a fragment of the cytochrome c oxidase I mitochondrial DNA (mtDNA) gene to examine diversity within P. australiensis and to assess the relative importance of amphidromy in its evolutionary history. We hypothesized that if transitions from an amphidromous to a freshwater life history were important, then we would find a number of divergent lineages restricted to single or groups of nearby drainages. Alternatively, if amphidromy was maintained within the species historically, we expected to find lineages distributed over many drainages. We assumed that the only way for divergence to occur within amphidromous lineages was if dispersal was limited to between nearby estuaries, which, during arid periods in the earth's history, became isolated from one another. We found nine highly divergent mtDNA lineages, estimated to have diverged from one another in the late Miocene/early Pliocene, when the climate was more arid than at present. Despite this, the geographic distribution of lineages and haplotypes within lineages did not support the notion of a stepping-stone model of dispersal between estuaries. We conclude that the extensive divergence has most likely arisen through a number of independent amphidromy-freshwater life history transitions, rather than via historical isolation of amphidromy populations. We also found evidence for extensive movement between coastal and inland drainages, supporting the notion that secondary contact between lineages may have occurred as a result of drainage rearrangements. Finally, our data indicate that P. australiensis is likely a complex of cryptic species, some of which are widely distributed, and others geographically restricted.

Genetic affinities among subspecies of a widespread Australian lycaenid butterfly, Ogyris amaryllis (Hewitson)

Genetic relationships among nominal subspecies of the lycaenid butterfly Ogyris amaryllis were investigated in eastern Australia. High levels of variation and population differentiation observed for allozyme markers were not consistent with subspecies boundaries. Partitioning of allozyme variation was explained better by arranging populations according to their larval host plant. Mitochondrial sequence data recovered a polyphyletic inland subspecies, with several peripheral subspecies showing reduced variation within this topology. Non-parametric topology tests rejected monophyly of the nominal subspecies and suggested that allopatric divergence is unlikely to account for the evolution of this complex. Genetic data, combined with information on distribution and ecology, are more consistent with a pattern of peripheral isolation associated with host-plant specialisation of coastal populations.

New partnerships between animal health services and public health agencies

As Veterinary Services and animal health organisations attempt to respond to a new era of emerging and re-emerging zoonotic diseases, their ability and skill in forming new strategic partnerships will be paramount. While these new partnerships are likely to include many relationships outside traditional Veterinary Services and animal agriculture, none will become more important than the formation of new animal health and public health partnerships. Episodes of emerging zoonoses are being increasingly recognised around the world and the confluence of people, animals and animal products today is unprecedented. Concurrently, a wide array of complex factors are also converging that will not only ensure the continuous emergence of zoonoses, but are also likely to drive the further increase and expansion of these diseases. This article discusses the need for the creation of more effective and co-operative partnerships in the face of new microbial threats, the complexity of both the formation and expansion of zoonoses, and the collective abilities of both human and animal health services to respond to them. Lessons learned from recent zoonotic epidemics supportthe need for co-ordinated research, interdisciplinary centres, integrated surveillance systems, response systems and infrastructures, and workforce development strategies. While there are some excellent examples of collaborative animal and public health relationships, there is no question that more and stronger partnerships among national and international organisations, both academic and private, will be necessary to meet the future challenges of emerging zoonoses and to manage their profound implications.

The head and body lice of humans are genetically distinct (Insecta: Phthiraptera, Pediculidae): evidence from double infestations

Little is known about the population genetics of the louse infestations of humans. We used microsatellite DNA to study 11 double infestations, that is, hosts infested with head lice and body lice simultaneously. We tested for population structure on a host, and for population structure among seven hosts that shared sleeping quarters. We also sought evidence of migration among louse populations. Our results showed that: (i) the head and body lice on these individual hosts were two genetically distinct populations; (ii) each host had their own populations of head and body lice that were genetically distinct to those on other hosts; and (iii) lice had migrated from head to head, and from body to body, but not between heads and bodies. Our results indicate that head and body lice are separate species.

Significant familial differences in the frequency of abortion and Toxoplasma gondii infection within a flock of Charollais sheep

A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27 families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since 1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. A total of 155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000–2003. Significant differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging between 0% and 48% (P<0·01). Significantly different infection frequencies with T. gondii were also observed for different families and ranged between 0% and 100% (P<0·01). Although the actual cause of each abortion was not verified, a highly significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection in the same families (P<0·01). The data presented here raise further questions regarding the significance of congenital transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods in the future.

High levels of congenital transmission of Toxoplasma gondii in longitudinal and cross-sectional studies on sheep farms provides evidence of vertical transmission in ovine hosts

Recent research suggests that vertical transmission may play an important role in sustaining Toxoplasma gondii infection in some species. We report here that congenital transmission occurs at consistently high levels in pedigree Charollais and outbred sheep flocks sampled over a 3-year period. Overall rates of transmission per pregnancy determined by PCR based diagnosis, were consistent over time in a commercial sheep flock (69%) and in sympatric (60%) and allopatric (41%) populations of Charollais sheep. The result of this was that 53.7 % of lambs were acquiring an infection prior to birth: 46.4% of live lambs and 90.0% of dead lambs (in agreement with the association made between T. gondii and abortion). No significant differences were observed between lamb sexes. Although we cannot distinguish between congenital transmission occurring due to primary infection at pregnancy or reactivation of chronic infection during pregnancy, our observations of consistently high levels of congenital transmission over successive lambings favour the latter.