Biology subjects

Pitcher, T. L.

Publications and source records attributed to Pitcher, T. L..

3 recordsLinked to original sources

bioRxiv2026

Magnetic sensitivity of cryptochrome 4a in domesticated quail with migratory origins

Magnetoreception, the ability of animals to sense the Earths magnetic field, is a fascinating biological phenomenon. Cryptochromes, in particular cryptochrome 4a (CRY4a), have emerged as potential key players in mediating magnetic sensing in various bird species. Building on an earlier investigation of magnetic field effects on European robin (Erithacus rubecula) CRY4a, we focus here on CRY4a from the common/Japanese quail (Coturnix coturnix/japonica). Japanese quail is one of the very small number of domesticated bird species whose wild forms are migratory. A detailed spectroscopic study of purified quail CRY4a shows that it has magnetic properties similar to robin CRY4a, suggesting that the quail could be a promising additional experimental model with which to unravel the intricacies of magnetoreception in migratory birds.

biophysics↗

bioRxiv2020

Cognitive tests that identify high risk of conversion to dementia in Parkinson's disease.

BackgroundPeople with Parkinsons disease who meet criteria for mild cognitive impairment are at increased risk of dementia. It is not known which tests are more effective than others for identifying the risk of dementia. MethodsAt baseline, we assessed performance on 21 neuropsychological test measures spanning five cognitive domains in a prospective longitudinal study of 196 non-demented people with Parkinsons. Elastic net logistic regression was used to identify a pair of tests from each cognitive domain that best predicted conversion to dementia over a four year period. The optimal tests most predictive of dementia were also determined when mild cognitive impairment was derived from a logistic-regression classifier that used all 21 measures simultaneously. ResultsWith two tests per domain, the resulting mild cognitive impairment group (N=87/196) captured 44 of 51 individuals who converted to PDD; the out-of-sample relative risk of PDD was 8.0 (95% CI [4.3, 24]), similar to that achieved with the full battery (N=102/196, capturing 45/51, relative risk = 6.9). When selecting tests regardless of domain, there was strong evidence for three tests: Trail Making part B (Executive), Map Search (Attention), and CVLT-II word list acquisition (Episodic Memory). The logistic-regression classifier achieved an out-of-sample AUC of 0.90 [0.84, 0.96] and a relative risk of 12 [6, 39]. ConclusionsAn abbreviated selection of neuropsychological tests can identify non-demented patients who have a high relative risk of progression to PDD.

neuroscience↗

bioRxiv2019

Nanopore sequencing of the glucocerebrosidase (GBA) gene in a New Zealand Parkinsons disease cohort

IntroductionBi-allelic mutations in the gene for glucocerebrosidase (GBA) cause Gaucher disease, an autosomal recessive lysosomal storage disorder. Gaucher disease causing GBA mutations in the heterozygous state are also high risk factors for Parkinsons disease (PD). GBA analysis is challenging due to a related pseudogene and structural variations (SVs) that can occur at this locus. We have applied and refined a recently developed nanopore DNA sequencing method to analyze GBA variants in a clinically assessed New Zealand longitudinal cohort of PD. MethodWe examined amplicons encompassing the coding region of GBA (8.9kb) from 229 PD cases and 50 healthy controls using the GridION nanopore sequencing platform, and Sanger validation. ResultsWe detected 23 variants in 21 PD cases (9.2% of patients). We detected modest PD risk variant p.N409S (rs76763715) in one case, p.E365K (rs2230288) in 12 cases, and p.T408M (rs75548401) in seven cases, one of whom also had p.E365K. We additionally detected the possible risk variants p.R78C (rs146774384) in one case, p.D179H (rs147138516) in one case which occurred on the same haplotype as p.E365K, and one novel variant c.335C>T or p.(L335=), that potentially impacts splicing of GBA transcripts. Additionally, we found a higher prevalence of dementia among patients with GBA variants. ConclusionThis work confirmed the utility of nanopore sequencing as a high-throughput method to identify known and novel GBA variants, and to assign precise haplotypes. Our observations may contribute to improved understanding of the effects of variants on disease pathogenesis, and to the development of more targeted treatments.

genetics↗