Biology subjects

Johnson, B. S.

Publications and source records attributed to Johnson, B. S..

4 recordsLinked to original sources

bioRxiv2026

Defective Hippocampus-Dependent Spatial Memory in Mouse Model of Polycystic ovary syndrome.

Polyendocrine metabolic ovarian syndrome (PMOS), formerly called as Polycystic Ovarian Syndrome (PCOS), is a complex endocrine disorder characterised by hyperandrogenism, oligo-or anovulation, and polycystic ovaries. Endocrine dysfunction in PMOS disrupts both hormonal and neurotransmitter balance, contributing to the psychological distress frequently reported by affected individuals. Although hormonal imbalances have been associated with memory impairments, their specific contribution to cognitive dysfunction in PMOS remains incompletely understood. In this study, we investigated the impact of PMOS on the hippocampus, a brain region critical for memory formation and highly sensitive to sex steroid modulation. A dehydroepiandrosterone (DHEA)-induced PMOS mouse model was employed to assess anxiety-like behaviour, locomotion, and memory. In the open field test (OFT), DHEA-treated mice spent significantly less time in the central zones and travelled a shorter total distance compared with controls, indicating increased anxiety-like behaviour. DHEA treatment also resulted in significantly impaired performance in both the object location test (OLT) and novel object recognition test (NORT), as reflected by a reduced discrimination index. Analysis of hippocampal immediate early gene expression using qRT-PCR revealed altered transcription of memory-related markers, including downregulation of Npas4 and Grin2a, and upregulation of Grin1, Arc, Egr1, and Egr2. Collectively, these findings suggest that elevated androgen levels induce anxiety- and depression-like behaviours and impair cognitive function, including spatial, recognition, and motor learning abilities, in PMOS. Our results further indicate that disrupted cortex-hippocampus communication may underlie these cognitive deficits, underscoring the importance of evaluating memory and cognitive health in women with PMOS to support brain health and overall well-being. Graphical summaryCartoon representation of the impact of hyperandrogenism on anxiety, spatial memory, and cognition in PMOS pathology. O_FIG O_LINKSMALLFIG WIDTH=132 HEIGHT=200 SRC="FIGDIR/small/721991v2_ufig1.gif" ALT="Figure 1"> View larger version (51K): org.highwire.dtl.DTLVardef@1d0125eorg.highwire.dtl.DTLVardef@1660d8aorg.highwire.dtl.DTLVardef@102ff8aorg.highwire.dtl.DTLVardef@1d6e06b_HPS_FORMAT_FIGEXP M_FIG C_FIG

animal behavior and cognition↗

bioRxiv2023

Triacylglycerol stability limits futile cycles and inhibition of carbon capture in oil-accumulating tobacco leaves

Engineering plant vegetative tissue to accumulate triacylglycerols (TAG, e.g., oil) can increase the amount of oil harvested per acre to levels that exceed current oilseed crops. Engineered Nicotiana tabacum (tobacco) lines that accumulate 15% to 30% oil of leaf dry weight resulted in starkly different metabolic phenotypes. In-depth analysis of the leaf lipid accumulation and 14CO2 metabolic tracing mechanistically described metabolic adaptations to the leaf oil engineering. An oil-for-membrane lipid tradeoff in the 15% oil line (referred to as HO) was surprisingly not further exacerbated when lipid production was enhanced to 30% (LEC2 line). The HO line exhibited a futile cycle that limited TAG yield through exchange with starch, altered carbon flux into various metabolite pools and end products, and suggested overlapping pathways of the glyoxylate cycle and photorespiration that limited CO2 assimilation by 50%. In contrast, inclusion of the LEC2 transcription factor in tobacco improved TAG stability, alleviated the TAG-to-starch futile cycle, and recovered CO2 assimilation and plant growth comparable to wild type but with much higher lipid levels in the leaves. Thus, the unstable production of storage reserves and futile cycling limit vegetative oil engineering approaches. The capacity to overcome futile cycles and maintain enhanced stable TAG levels in LEC2 demonstrated the importance of considering unanticipated metabolic adaptations while engineering vegetative oil crops.

plant biology↗

bioRxiv2020

No evidence for whole-chromosome dosage compensation or global transcriptomic expression differences in spontaneously-aneuploid mutation accumulation lines of Saccharomyces cerevisiae

Aneuploidy, the state in which an organisms genome contains one or more missing or additional chromosomes, often causes widespread genotypic and phenotypic effects. Most often, aneuploidies are deleterious; the most common examples in humans being Downs syndrome (Trisomy 21) and Turners syndrome (monosomy X). However, aneuploidy is surprisingly common in wild yeast populations. In recent years, there has been debate as to whether yeast contain an innate dosage compensation response that operates at the gene, chromosome, or the whole-genome level, or if natural isolates are robust to aneuploidy without such a mechanism. In this study, we tested for differential gene expression in 20 aneuploid and 16 euploid lines of yeast from two previous mutation accumulation experiments, where selection was minimized and therefore aneuploidies arose spontaneously. We found no evidence for whole-chromosome dosage compensation in aneuploid yeast but did find some evidence for attenuation of expression on a gene-by-gene basis. We additionally found that aneuploidy has no effect on the expression of the rest of the genome (i.e. "trans" genes), and that very few mutually exclusive aneuploid lines shared differentially expressed genes. However, we found there was a small set of genes that exhibited a shared expression response in the euploid lines, suggesting an effect of mutation accumulation on gene expression. Our findings contribute to our understanding of aneuploidy in yeast and support the hypothesis that there is no innate dosage compensation mechanism at the whole-chromosome level.

genetics↗

bioRxiv2019

Evaluation of Reproducibility in Urology Publications

Take Home MessageMany components of transparency and reproducibility are lacking in urology publications, making study replication, at best, difficult.\n\nIntroductionReproducibility is essential for the integrity of scientific research. Reproducibility is measured by the ability of investigators to replicate the outcomes of an original publication by using the same materials and procedures.\n\nMethodsWe sampled 300 publications in the field of urology for assessment of multiple indicators of reproducibility, including material availability, raw data availability, analysis script availability, pre-registration information, links to protocols, and whether the publication was freely available to the public. Publications were also assessed for statements about conflicts of interest and funding sources.\n\nResultsOf the 300 sample publications, 171 contained empirical data and could be analyzed for reproducibility. Of the analyzed articles, 0.58% (1/171) provided links to protocols, and none of the studies provided analysis scripts. Additionally, 95.91% (164/171) did not provide accessible raw data, 97.53% (158/162) did not provide accessible materials, and 95.32% (163/171) did not state they were pre-registered.\n\nConclusionCurrent urology research does not consistently provide the components needed to reproduce original studies. Collaborative efforts from investigators and journal editors are needed to improve research quality, while minimizing waste and patient risk.

scientific communication and education↗