Search

INTRODUCTION: Overlooking the heterogeneity in Alzheimer's disease (AD) may lead to diagnostic delays and failures. Neuroanatomical normative modeling captures individual brain variation and may inform our understanding of individual differences in AD‐related atrophy. METHODS: We applied neuroanatomical normative modeling to magnetic resonance imaging from a real‐world clinical cohort with confirmed AD (n = 86). Regional cortical thickness was compared to a healthy reference cohort (n = 33,072) and the number of outlying regions was summed (total outlier count) and mapped at individual‐ and group‐levels. RESULTS: The superior temporal sulcus contained the highest proportion of outliers (60%). Elsewhere, overlap between patient atrophy patterns was low. Mean total outlier count was higher in patients who were non‐amnestic, at more advanced disease stages, and without depressive symptoms. Amyloid burden was negatively associated with outlier count. DISCUSSION: Brain atrophy in AD is highly heterogeneous and neuroanatomical normative modeling can be used to explore anatomo‐clinical correlations in individual patients. [ABSTRACT FROM AUTHOR]

The current theoretical framework suggests that tripartite positive feedback relationships between soil biodiversity, fertility and plant productivity are universal. However, empirical evidence for these relationships at the continental scale and across different soil depths is lacking., We investigate the continental-scale relationships between the diversity of microbial and invertebrate-based soil food webs, fertility and above-ground plant productivity at 289 sites and two soil depths, that is 0-10 and 20-30 cm, across Australia., Soil biodiversity, fertility and plant productivity are strongly positively related in surface soils. Conversely, in the deeper soil layer, the relationships between soil biodiversity, fertility and plant productivity weaken considerably, probably as a result of a reduction in biodiversity and fertility with depth. Further modeling suggested that strong positive associations among soil biodiversity-fertility and fertility-plant productivity are limited to the upper soil layer (0-10 cm), after accounting for key factors, such as distance from the equator, altitude, climate and physicochemical soil properties., These findings highlight the importance of surface soil biodiversity for soil fertility, and suggest that any loss of surface soil could potentially break the links between soil biodiversity-fertility and/or fertility-plant productivity, which can negatively impact nutrient cycling and food production, upon which future generations depend. [ABSTRACT FROM AUTHOR]

The large and complex genome of wheat makes genetic and genomic analysis in this important species both expensive and resource intensive. The application of next-generation sequencing technologies is particularly resource intensive, with at least 17 Gbp of sequence data required to obtain minimal (1×) coverage of the genome. A similar volume of data would represent almost 40× coverage of the rice genome. Progress can be made through the establishment of consortia to produce shared genomic resources. Australian wheat genome researchers, working with Bioplatforms Australia, have collaborated in a national initiative to establish a genetic diversity dataset representing Australian wheat germplasm based on whole genome next-generation sequencing data. Here, we describe the establishment and validation of this resource which can provide a model for broader international initiatives for the analysis of large and complex genomes. [ABSTRACT FROM AUTHOR]

The hemi-biotrophic fungus Venturia inaequalis infects members of the Maloideae, causing the economically important apple disease, scab. The plant–pathogen interaction of Malus and V. inaequalis follows the gene-for-gene model. cDNA libraries were constructed, and bioinformatic analysis of the resulting expressed sequence tags (ESTs) was used to characterize potential effector genes. Effectors are small proteins, secreted in planta, that are assumed to facilitate infection. Therefore, a cDNA library was constructed from a compatible interaction. To distinguish pathogen from plant sequences, the library was probed with genomic DNA from V. inaequalis to enrich for pathogen genes, and cDNA libraries were constructed from in vitro-grown material. A suppression subtractive hybridization library enriched for cellophane-induced genes was included, as growth on cellophane may mimic that in planta, with the differentiation of structures resembling those formed during plant colonization. Clustering of ESTs from the in planta and in vitro libraries indicated a fungal origin of the resulting non-redundant sequence. A total of 937 ESTs was classified as putatively fungal, which could be assembled into 633 non-redundant sequences. Sixteen new candidate effector genes were identified from V. inaequalis based on features common to characterized effector genes from filamentous fungi, i.e. they encode a small, novel, cysteine-rich protein, with a putative signal peptide. Three of the 16 candidates, in particular, conformed to most of the protein structural characteristics expected of fungal effectors and showed significant levels of transcriptional up-regulation during in planta growth. In addition to candidate effector genes, this collection of ESTs represents a valuable genomic resource for V. inaequalis. [ABSTRACT FROM AUTHOR]

Background: The clinical use of amyloid‐PET imaging (API) is guided by a set of published appropriate use criteria (Johnson et al., 2013). Patients meeting these criteria have suspected Alzheimer's Disease (AD) accompanied by an atypical clinical presentation leading to substantial diagnostic uncertainty. Previous large‐cohort studies have investigated this clinical population from a diagnostic standpoint, looking at the impact of using amyloid‐PET to elucidate the aetiology of impairment. However, data concerning their clinical phenotypes is lacking. In this study, we investigated the prevalence of depression and its association with Alzheimer's pathology in Memory Clinic patients who received clinical API. Method: We reviewed the clinical records of 185 older adults (mean age 67.09±9.35, 49% females) who were assessed in our Clinic between January 2017 and June 2019 and received API. Referral to amyloid‐PET followed a multidisciplinary meeting and was in line with appropriate use criteria. Patients were categorised as 'D+', with history of depression, if they had received a previous depression diagnosis and/or if they had a history of depressive symptoms. Overall depression prevalence was compared with published cohort data. Amyloid‐PET results (positive versus negative) were compared between the D+ and the D‐ (without history of depression) groups. In D+ patients, we determined the onset and status of depressive symptoms. Result: Of 185 patients, 98 (53%) had a history of depression. Of these, 89 individuals had ongoing symptoms at the time of referral to our Clinic and 59 of them were on antidepressants. The mean age of depression onset was 58.25(±12.25) years. Depression prevalence in this cohort was considerably higher than that generally seen in memory clinics (20%; Knapskog et al., 2014) and in healthy older adults (19%; McDougall et al.,2017). Depression history was not associated with amyloid‐PET results (%positive: D+ 39.8%, D‐ 50.6%, χ2(1)=2.16 p=.14), age (mean±SD: D+ 66.47±9.03 years, D‐ 67.79±9.71 years, t(183)=‐.95 p=.342), or sex (%female: D+ 44.9%, D‐ 52.9%, χ2(1)=.1.17 p=.304). Conclusion: Depression prevalence is high in patients referred for clinical amyloid‐PET imaging and is independent of the presence or absence of Alzheimer's pathology. Depression may be one of the key contributors to diagnostic uncertainty in this group. [ABSTRACT FROM AUTHOR]