Accurate MS-based Rab10 Phosphorylation Stoichiometry Determination as Readout for LRRK2 Activity in Parkinson's Disease

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Highlights

• •MS-based clinical assay that accurately determines phospho Rab10 occupancy.
• •Stable isotope labeled phosphopeptide injected as a standard with endogenous tryptic phospho Rab peptide for accurate ratio determination.
• •Determination of pRab levels in neutrophils of Parkinson disease patients.
• •Relevance of pRab levels as marker of PD.

     

Discovery of Species-unique Peptide Biomarkers of Bacterial Pathogens by Tandem Mass Spectrometry-based Proteotyping

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Highlights

• •Discovery of peptide biomarker candidates of respiratory tract pathogens S. pneumoniae, H. influenzae, M. catarrhalis and S. aureus as target pathogens.
• •Peptide biomarker candidates were experimentally verified in clinical samples.
• •Targeted MS using promising peptide biomarker candidates shown as proof-of-concept.

     

Increased Production of Paired Helical Filament Epitopes in a Cell Culture System Reduces the Turnover of τ

Abstract: To investigate the regulation of posttranslational modifications of τ that might be pertinent to the production of the paired helical filament (PHF) of Alzheimer's disease, we incubated human neuroblastoma cells with the protein phosphatase inhibitor okadaic acid. This treatment results in increased immunoreactivity of τ with the monoclonal antibodies Alz-50, PHF-1, T3P, and NP8, a reduction in Tau-1 immunoreactivity, and an elevation in apparent molecular weight of τ. Moreover, our data demonstrate that accumulation of phosphates in τ leads to a decrease in the turnover rate of τ in the neuroblastoma cells. It is suggested that similar build-up of hyperphosphorylated τ in the neuronal perikarya may represent an early event in PHF formation. The present system facilitates the investigation of regulatory mechanisms governing the occurrence of PHF epitopes, their effects on neuronal cell metabolism, and possible pharmacological intervention.     

Shifts in bacterial communities of two caribbean reef-building coral species affected by white plague disease

Coral reefs are deteriorating at an alarming rate mainly as a consequence of the emergence of coral diseases. The white plague disease (WPD) is the most prevalent coral disease in the southwestern Caribbean, affecting dozens of coral species. However, the identification of a single causal agent has proved problematic. This suggests more complex etiological scenarios involving alterations in the dynamic interaction between environmental factors, the coral immune system and the symbiotic microbial communities. Here we compare the microbiome of healthy and WPD-affected corals from the two reef-building species Diploria strigosa and Siderastrea siderea collected at the Tayrona National Park in the Caribbean of Colombia. Microbiomes were analyzed by combining culture-dependent methods and pyrosequencing of 16S ribosomal DNA (rDNA) V5-V6 hypervariable regions. A total of 20 410 classifiable 16S rDNA sequences reads were obtained including all samples. No significant differences in operational taxonomic unit diversity were found between healthy and affected tissues; however, a significant increase of Alphaproteobacteria and a concomitant decrease in the Beta- and Gammaproteobacteria was observed in WPD-affected corals of both species. Significant shifts were also observed in the orders Rhizobiales, Caulobacteriales, Burkholderiales, Rhodobacterales, Aleteromonadales and Xanthomonadales, although they were not consistent between the two coral species. These shifts in the microbiome structure of WPD-affected corals suggest a loss of community-mediated growth control mechanisms on bacterial populations specific for each holobiont system.     

Monitoring the early aggregatory behaviour and size of Aβ1-42 in the absence & presence of metal ions using dynamic light scattering

Background and aimAβ₁₋₄₂ is an amyloidogenic peptide found within senile plaques extracted from those who died with a diagnosis of Alzheimer’s disease. The potent neurotoxicity of this peptide is related to its propensity to form aggregated conformations in vivo, a process that is influenced by the species and concentration of metal ions present within the local environment. This study examines the impact of different metals upon the early aggregatory behaviour and size of Aβ₁₋₄₂ under simulated physiological conditions.MethodsThe size and aggregatory behaviour of Aβ₁₋₄₂ in the presence and absence of metal ions was monitored during the initial 30 min of fibril formation in real-time using dynamic light scattering.ResultsIntensity scattering measurements showed a clear tendency towards aggregation with regards to Aβ₁₋₄₂ only solutions (10 μM). Both equimolar Al³⁺ & Cu²⁺ lowered and stabilised the dimensions of Aβ₁₋₄₂ aggregates; however, a diminutive but significant increase in size was still observed over a 30-min period. While excess Al³⁺ continued to supress the size of Aβ_1−42, a 10-fold increase in the concentration of Cu²⁺ accelerated peptide aggregation relative to that observed for equimolar metal but not compared to Aβ₁₋₄₂ alone.ConclusionThese results infer that Al³⁺ ions stabilise and aid in the maintenance of smaller, toxic intermediates while excess Cu²⁺ facilitates the formation of larger, more inert, amorphous species exceeding 1 μm in size. Furthermore, we propose that metal-induced toxicity of Aβ₁₋₄₂ is reflective of their ability to preserve smaller oligomeric species in vitro.     

Dysregulation of neural calcium signaling in Alzheimer disease,bipolar disorder and schizophrenia

Neurons have highly developed Ca²⁺ signaling systems responsible for regulating a large number of neural functions such as the control of brain rhythms, information processing and the changes in synaptic plasticity that underpin learning and memory. The tonic excitatory drive, which is activated by the ascending arousal system, is particularly important for processes such as sensory perception, cognition and consciousness. The Ca²⁺ signaling pathway is a key component of this arousal system that regulates the neuronal excitability responsible for controlling the neural brain rhythms required for information processing and cognition. Dysregulation of the Ca²⁺ signaling pathway responsible for many of these neuronal processes has been implicated in the development of some of the major neural diseases in man such as Alzheimer disease, bipolar disorder and schizophrenia. Various treatments, which are known to act by reducing the activity of Ca²⁺ signaling, have proved successful in alleviating the symptoms of some of these neural diseases.     

Burden of disease due to cancer in a Southern Brazilian state

Background: Despite the considerable epidemiological relevance of cancer in developing countries, there are very few studies of the burden related to cancer. The aim of this study was to present and discuss data from a burden-of-cancer study performed in a Southern Brazilian state. Methods: An epidemiological study of ecological design was performed to calculate the disability-adjusted life year (DALY) index. The study was based on records of individuals admitted and treated for cancer in the Brazilian National Health System Hospitals, or individuals who had died of cancer while residing in the state of Santa Catarina in 2008. Results: A total of 73,872.9 DALYs were estimated, which generated a rate of 1220.5 DALYs/100,000 inhabitants. The highest DALYs were those for cancer of the trachea, bronchus and lung with 179.0/100,000 inhabitants, gastric cancer with 101.7/100,000 inhabitants, and breast cancer with 99.7/100,000 inhabitants. The percentage contribution of the DALY component varied according to cancer type; however, mortality was the major component in all types. The highest rates were observed in 60–69-year-olds with 6071.3/100,000 inhabitants, in 70–79-year-olds with 5095.4/100,000 inhabitants, and in 45–59-year-olds with 3189.0 DALY/100,000 inhabitants; 53.7% of DALYs occurred in males. Conclusions: The greatest burden of disease due to cancer in Santa Catarina was attributed to cancer of the trachea, bronchus and lung, followed by gastric and breast cancers. The mortality component was responsible for the greatest burden.