During routine vegetation health surveys in the southwest of Western Australia (SWWA), several Phytophthora isolates with affinity to Clade 6a have been recovered. In this study, all known taxa from ...Clade 6a, P. inundata, P. humicola, P. gemini, P.
'walnut' and P. 'personii', and the new isolates were compared based on morphology and DNA sequence data from three nuclear genes and two mitochondrial genes resulting in the description of five new species, P. balyanboodja, P. condilina, P. cooljarloo, P. kwongonina
and P. pseudorosacearum. With the exception of P. gemini and P. humicola, all species from Clade 6a have been recovered from natural ecosystems in SWWA. These species are morphologically similar, with predominantly ovoid sporangia and nested and extended internal
proliferation. If oospores are present, they tend to be aplerotic with paragynous antheridia mostly attached adjacent to the oogonial stalk. They can all grow at 35°C and have a fast growth rate on most agar media. These species have all been recovered from the rhizosphere soil and dead
and dying plants within dry kwongon heathlands, often from water gaining sites and frequently from very isolated areas. The radiation, origin and potential ecological role of these species are discussed.
Many obligate blood-sucking arthropods rely on symbiotic bacteria to provision essential B vitamins that are either missing or at sub-optimal levels in their nutritionally challenging blood diet. The ...poultry red mite
Dermanyssus gallinae
, an obligate blood-feeding ectoparasite, is a serious threat to the hen egg industry. Poultry red mite infestation has a major impact on hen health and welfare and causes a significant reduction in both egg quality and production. Thus far, the identity and biological role of nutrient provisioning bacterial mutualists from
D. gallinae
are little understood. Here, we demonstrate that an obligate intracellular bacterium of the
Rickettsiella
genus is detected in
D. gallinae
mites collected from 63 sites (from 15 countries) across Europe. In addition, we report the genome sequence of
Rickettsiella
from
D. gallinae
(
Rickettsiella – D. gallinae
endosymbiont;
Rickettsiella
DGE).
Rickettsiella
DGE has a circular 1.89Mbp genome that encodes 1,973 proteins. Phylogenetic analysis confirms the placement of
Rickettsiella
DGE within the
Rickettsiella
genus, related to a facultative endosymbiont from the pea aphid and
Coxiella
-like endosymbionts (CLEs) from blood feeding ticks. Analysis of the
Rickettsiella
DGE genome reveals that many protein-coding sequences are either pseudogenized or lost, but
Rickettsiella
DGE has retained several B vitamin biosynthesis pathways, suggesting the importance of these pathways in evolution of a nutritional symbiosis with
D. gallinae
.
In silico
metabolic pathway reconstruction revealed that
Rickettsiella
DGE is unable to synthesize protein amino acids and, therefore, amino acids are potentially provisioned by the host. In contrast,
Rickettsiella
DGE retains biosynthetic pathways for B vitamins: thiamine (vitamin B1)
via
the salvage pathway; riboflavin (vitamin B2) and pyridoxine (vitamin B6) and the cofactors: flavin adenine dinucleotide (FAD) and coenzyme A (CoA) that likely provision these nutrients to the host.
Current and future information systems require a better understanding of the interactions between users and systems in order to improve system use and, ultimately, success. The use of personas as ...design tools is becoming more widespread as researchers and practitioners discover its benefits. This paper presents an empirical study comparing the performance of existing qualitative and quantitative clustering techniques for the task of identifying personas and grouping system users into those personas. A method based on Factor (Principal Components) Analysis performs better than two other methods which use Latent Semantic Analysis and Cluster Analysis as measured by similarity to expert manually defined clusters.
The medial prefrontal cortex (MPFC) is a key brain area in depressive symptomatology; specifically, glutamate (Glu) has been reported to play a significant role in major depression (MD) in this area. ...MPFC Glu levels are sensitive to ovarian hormone fluctuations and pregnancy and the postpartum period are associated with the most substantial physiological alterations of female hormones. It is therefore logical to measure MPFC Glu levels in women with postpartum depression (PPD). Using in vivo magnetic resonance spectroscopy (MRS) at a field strength of 3 T, we acquired single-voxel spectra from the MPFC of 12 women with PPD and 12 healthy controls (HCs) matched for postpartum scan timing. Water-referenced MPFC Glu levels were measured using a MRS technique that allowed us to be specific for Glu with very little glutamine contamination. The concentrations of other water-quantified brain metabolites such as glycerophosphorylcholine plus phosphorylcholine, N-acetylaspartate (NAA), and creatine plus phosphocreatine were measured in the same MR spectra. MPFC Glu levels were higher in women with PPD (7.21±1.20) compared to matched HCs (6.04±1.21). There were no differences between groups for other brain metabolites measured. These findings suggest an association between Glu dysregulation in the MPFC and PPD. Whether the pathophysiology of PPD differs from the pathophysiology of MD remains to be determined. Further investigations are needed to determine the chronological associations between the occurrence of symptoms of PPD and the onset of changes in MPFC Glu levels.
Diseases caused by pathogens, alone or in combination with other stress factors, are a major threat to the future health of urban forests. Root diseases caused by
Phytophthora
species are frequently ...evident in urban environments due to conducive environments for these pathogens, and to conditions predisposing trees to attack. Urban environments are also an important pathway for the introduction of
Phytophthora
species into novel ecosystems. We have detected many different
Phytophthora
species from dying and declining trees in the urban and peri-urban environment, and for many of these species, little is known about their host range
.
Therefore, the aim of this study was to examine the host range of 19
Phytophthora
species, including many recently described species, against fifteen tree species commonly used in urban plantings in Perth, Western Australia. Excised branches of each tree species were under-bark inoculated with each
Phytophthora
species, incubated and lesions were measured after 8 days. Six
Phytophthora
species were pathogenic to all fifteen-tree species, with ~75% of the species each causing disease in ≥85% of plant hosts. All
Phytophthora
species formed lesions in
Eucalyptus marginata
and
Corymbia calophylla. Phytophthora cinnamomi, P. pseudocryptogea,
and
P. citrophthora
were the most pathogenic species causing the largest lesions in most of these trees species. It is likely many of these
Phytophthora
species have a negative impact on the health of urban forests where they are present.
Many studies over recent years have recognised
Phytophthora cryptogea
as a species complex, with several distinct lineages perhaps representing as yet undescribed species. Additionally, the taxonomic ...status of the related species
P. erythroseptica
is also a matter of controversy. In this study, phylogenetic relationships were clarified using nuclear (internal transcribed spacers, ß-tubulin, heat shock protein 90, elicitin) and mitochondrial (cytochrome c oxidase subunit I, NADH dehydrogenase subunit I) gene regions. Our results showed three distinct phylogenetic lineages within
P. cryptogea
in combined nuclear and mitochondrial gene trees. The molecular divergence observed among these three phylogenetic lineages justifies their re-description as separate species. The first group, including the type isolate, is
P. cryptogea
sensu stricto, the second group corresponds to the undescribed taxon
P
. sp.
kelmania
and the third group is described here as
P. pseudocryptogea
sp. nov. Although some morphological differences between
P. cryptogea
and
P. pseudocryptogea
were notable, they were not sufficient to reliably distinguish these species. Moreover, in all of our phylogenetic trees (with the exception of elicitin),
P. erythroseptica
isolates were in a strongly supported monophyletic clade. This clade shares a recent common ancestor with
P. cryptogea
sensu stricto, but is clearly distinct from
P. cryptogea
. Our results therefore confirmed the position of
P. erythroseptica
as a distinct species and a close relative to the
P. cryptogea
species complex.
Background: Achilles tendinopathy is a common condition amongst distance runners due to the cumulative repetitive overload of the tendon. Gastrocnemius weakness and inflexibility can predispose to ...this condition. Thesepredisposing functional deficits could have architectural underpinnings, but the gastrocnemius architecture of distance runners with Achilles tendinopathy has not been previously described or compared to the architecture of healthy distance runners.
Objectives: We aimed to investigate the differences in gastrocnemius architecture between distance runners withAchilles tendinopathy and uninjured counterparts.
Methods: Twenty distance runners (10 with Achilles tendinopathy; 10 uninjured) were recruited to this study. Ultrasound measurement of the gastrocnemius muscle architecture (pennation angle; fascicle length; muscle thickness; muscle belly length; muscle volume; physiological cross-sectional area) was performed.
Results: Gastrocnemius Medial Head (GM) fascicle length was significantly greater (p = 0.02), whilst the physiological cross-sectional area (PCSA) was significantly less (p = 0.01) in the case group. Gastrocnemius Lateral Head (GL) pennation angle (p = 0.01) and PCSA (p = 0.01) were significantly lower, whilst fascicle length was significantly greater (p = 0.01) in the case group. There were no significant between-group differences in GM and GL muscle thickness, muscle belly length, or muscle volume.
Conclusion: Components of gastrocnemius architecture differ significantly between distance runners with Achillestendinopathy and uninjured controls in our study sample. This study cannot infer whether these results are secondary or predisposing to the condition. Further longitudinal investigation is required to explore these relationships further.
Scabies is one of the most common and widespread parasitic skin infections globally, affecting a large range of mammals including humans, yet the molecular biology of Sarcoptes scabiei is ...astonishingly understudied. Research has been hampered primarily due to the difficulty of sampling or culturing these obligatory parasitic mites. A further and major impediment to identify and functionally analyse potential therapeutic targets from the recently emerging molecular databases is the lack of appropriate molecular tools.
We performed standard BLAST based searches of the existing S. scabiei genome databases using sequences of genes described to be involved in RNA interference in Drosophila and the mite model organism Tetranychus urticae. Experimenting with the S. scabiei mu-class glutathione S-transferase (SsGST-mu1) as a candidate gene we explored the feasibility of gene knockdown in S. scabiei by double-stranded RNA-interference (dsRNAi).
We provide here an analysis of the existing S. scabiei draft genomes, confirming the presence of a double stranded RNA (dsRNA) - mediated silencing machinery. We report for the first time experimental gene silencing by RNA interference (RNAi) in S. scabiei. Non-invasive immersion of S. scabiei in dsRNA encoding an S. scabiei glutathione S-transferase mu-class 1 enzyme (SsGST-mu1) resulted in a 35% reduction in the transcription of the target gene compared to controls.
A series of experiments identified the optimal conditions allowing systemic experimental RNAi without detrimental side effects on mite viability. This technique can now be used to address the key questions on the fundamental aspects of mite biology and pathogenesis, and to assess the potential therapeutic benefits of silencing S. scabiei target genes.
Invasive mammals represent a critical threat to island biodiversity; eradications can result in ecological restoration yet may fail in the absence of key population parameters. Over-browsing by ...invasive Sitka black-tailed deer (Odocoileus hemionus sitkensis) is causing severe ecological and cultural impacts across the Haida Gwaii archipelago (Canada). Previous eradication attempts demonstrate forest regeneration upon deer removal, but reinvasion reverses conservation gains. Here we use restriction-site associated DNA sequencing (12,947 SNPs) to investigate connectivity and gene flow of invasive deer (n = 181) across 15 islands, revealing little structure throughout Haida Gwaii and identifying the large, central island of Moresby (>2600 km
) as the greatest source of migrants. As a result, the archipelago itself should be considered the primary eradication unit, with the exception of geographically isolated islands like SGang Gwaay. Thus, limiting eradications to isolated islands combined with controlled culling and enhanced biosecurity may be the most effective strategies for achieving ecological restoration goals.
Rubus anglocandicans is the most widespread and abundant blackberry species within the European blackberry (Rubus fruticosus) aggregate in Western Australia (WA). European blackberry is also one of ...the 32 Weeds of National Significance in Australia. A disease recorded as ‘blackberry decline’ was first observed in some blackberry sites in WA in 2006. A disease survey was conducted in the Manjimup‐Pemberton region along the Warren and Donnelly River catchments in WA between 2010 and 2012. Phytophthora amnicola, P. bilorbang, P. cryptogea, P. inundata, P. litoralis, P. multivora, P. taxon personii, P. thermophila and a P. thermophila × amnicola hybrid were recovered from declining and adjacent decline‐free sites, as well as from streams and rivers. Phytophthora cinnamomi was isolated from dying Banksia and Eucalyptus species from two non‐decline sites. Of these species, P. bilorbang and P. cryptogea were more pathogenic than the others in under‐bark inoculations using excised stems (primocanes), in planta primocane inoculations in blackberry growing wild in native forest stands, and in glasshouse pot trials. It was concluded that blackberry decline is a complex syndrome and Phytophthora species, in particular P. bilorbang and P. cryptogea, together with temporary inundation, are major biotic and abiotic factors contributing to blackberry decline.
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