Biology subjects

Logan, J.

Publications and source records attributed to Logan, J..

7 recordsLinked to original sources

bioRxiv2025

Motivational trade-offs in a cockroach: impact of conditions, injury, and development

The ability to flexibly trade off access between competing or antagonistic stimuli ("motivational trade-offs") is a key criterion for assessing whether animals can feel pain. However, in some commonly farmed, exterminated, and studied insect orders such as Blattodea (cockroaches and termites), the ability to make motivational trade-offs is unconfirmed, which makes it difficult to assess their welfare needs. Here we gave cockroaches (Blaptica dubia) a choice between access to shelter or to nutrition across a series of linked experiments to assess whether they are capable of motivational trade-offs and if they are flexibly adjusted due to external conditions and/or injury and develop across ontogeny. We found cockroaches avoided a food reward when it was exposed to light (a behavioural trade-off), but they did not adjust their preference flexibly in response to lighting intensity or increased hunger level (no motivational trade-off). We did find that injury reduces willingness to accept light exposure when accessing nutrition, which is consistent with the idea of the sensation of pain reducing risk-taking behaviour. Finally, we showed that juvenile cockroaches match adults in not making a motivational trade-off. All together our results provide much-needed evidence for criteria of whether insects feel pain and suggest upper limits to cognitive complexity and flexibility in Blattodea. These findings can be integrated with other neurological and behavioural measures to help us judge how we treat insects and other invertebrates in our care.

animal behavior and cognition↗

bioRxiv2025

Sensitive, non-invasive detection of chronic wasting disease in wild and captive white-tailed deer using fecal volatile profiling

Chronic Wasting Disease (CWD) is a universally fatal, transmissible prion disease affecting cervids. Primarily found among deer populations in North America, the disease has spread across the continent and made forays into Europe and Asia as well. Currently, accurate methods for detecting CWD infection require post-mortem dissection of the lymph nodes and brainstem of affected animals. New, high-sensitivity methods of detecting CWD in living animals are sorely needed to help curb spread of this devastating disease in farmed and wild deer. Here, we use two-dimensional gas chromatography-mass spectrometry (GCxGC-MS) to detect volatile organic compounds (VOCs) released from the feces of white-tailed deer (WTD) for differentiation of the feces of CWD-negative and CWD-positive animals. We report four discrete VOCs in captive WTD and ten discrete VOCs in wild WTD, with which we can discriminate CWD-positive and CWD-negative samples. Additionally, we evaluate the ability to detect CWD early during disease progression, by comparing samples from the early stage of infection with samples from late stage and uninfected WTD. Our data suggest that detection of VOCs from the feces of WTD -- both in captive and wild populations -- can serve as a highly sensitive and non-invasive technique for identifying CWD infection in living animals.

microbiology↗

bioRxiv2020

Chronic optogenetic stimulation of hippocampal engrams variably modulates social behaviors in mice

The hippocampus processes both spatial-temporal information and emotionally salient experiences. To test the functional properties of discrete sets of cells in the dorsal dentate gyrus (dDG), we examined whether chronic optogenetic reactivation of these ensembles was sufficient to modulate social behaviors in mice. We found that chronic reactivation of dDG cells in male mice was sufficient to enhance social behaviors in a female exposure task when compared to pre-stimulation levels. However, chronic reactivation of these cells was not sufficient to modulate group differences in a separate subset of social behaviors, and multi-region analysis of neural activity did not yield detectable differences in immediate-early gene expression or neurogenesis, suggesting a dissociation between our chronic stimulation-induced behavioral effects and underlying neural responses. Together, our results demonstrate that chronic optogenetic stimulation of cells processing valent experiences enduringly and unidirectionally modulates social interactions between male and female mice.

neuroscience↗

bioRxiv2020

A trans-eQTL network regulates osteoclast multinucleation and bone mass

Functional characterisation of cell-type specific regulatory networks is key to establish a causal link between genetic variation and phenotype. The osteoclast offers a unique model for interrogating the contribution of co-regulated genes to in vivo phenotype as its multinucleation and resorption activities determine quantifiable skeletal traits. Here we took advantage of a trans-regulated gene network (MMnet, macrophage multinucleation network) which we found to be significantly enriched for GWAS variants associated with bone-related phenotypes. We found that the network hub gene Bcat1 and seven other co-regulated MMnet genes out of 13, regulate bone function. Specifically, global (Pik3cb-/-, Atp8b2+/-, Igsf8-/-, Eml1-/-, Appl2-/-, Deptor-/-) and myeloid-specific Slc40a1{Delta}LysMCre knockout mice displayed abnormal bone phenotypes. We report antagonizing effects of MMnet genes on bone mass in mice and osteoclast multinucleation/resorption in humans with strong correlation between the two. These results identify MMnet as a functionally conserved network that regulates osteoclast fusion and bone mass. Impact statementWe took advantage of the osteoclast whose multinucleation properties correlate with bone mass. We show that a trans-regulated gene network (MMnet) controls skeletal homeostasis through osteoclast multinucleation and function.

cell biology↗

bioRxiv2019

Peculiar cases of a \"sleeping\" brain in alert cancer patients

Cognitive and constitutional symptomatology is common in cancer patients but the causes are not well understood. To investigate whether cancers cause these symptoms by changing cerebral metabolism, we measured the cerebral rate of glucose consumption (CMRglc) in patients diagnosed with a lung lesion.\n\nMethodsThe CMRglc was quantified in 20 patients undergoing 18F-FDG PET for lesion staging. The cognitive status was assessed by neuropsychological testing.\n\nResultsParadoxically, despite being alert three of the patients had CMRglc typical of people who are in deep sleep or anesthetized. All three had cancers, two died within 2 months of scanning. Remaining patients including four with early stage cancer had CMRglc within normal range.\n\nConclusionsWe speculate that the low CMRglc reflects a switch to an alternative energy source that is mediated by cancers remotely. Identifying the underlying mechanism and the alternative energy sources may help to understand how cancers can change body metabolism.

cancer biology↗

bioRxiv2019

Perceptions, attitudes and practices towards scabies in communities on the Bijagos Islands, Guinea-Bissau

IntroductionScabies is highly endemic among impoverished populations and has been recently included in the WHOs list of neglected tropical diseases (NTDs). Community support and behavioural changes are essential for the success of control interventions. This study aimed to explore beliefs, prevention attitudes and health care-seeking behaviours towards scabies in the Bijagos Archipelago of Guinea-Bissau. MethodsData were collected through two methods. Community key informants (community members, community health workers, healthcare workers and traditional healers) were interviewed using snowball sampling. A questionnaire covering perceptions, attitudes and practices was administered to community members using random cluster sampling. Thematic analysis of qualitative data was applied to identify themes. Descriptive statistics were used for quantitative data analysis. ResultsThere was a satisfactory awareness about scabies, but perceptions about disease causation and transmission were imprecise. Misconceptions about personal hygiene as the primary measure for scabies prevention were recurrent. Some participants recognised the importance of early treatment to interrupt transmission. Treatment of close contacts was not considered important. Costs were the main determining factor for treatment choice between traditional healer and the local health centre. Late presentation and delayed treatment were common and associated with poverty and stigmatisation. Scabies impaired quality of life by affecting social interactions, health, fitness to work and school attendance. ConclusionsThere is a need to improve education, recognition, management and affordable access to treatment. Community education, healthcare workers training and skin NTDs integrated control programmes should address the challenges highlighted in this study. Authors SummaryScabies is a common skin infection in low income settings. We conducted a study in Guinea-Bissau to explore the knowledge, attitudes and practices about scabies. We conducted interviews with healthcare workers, traditional healers and community members and additionally used an oral-administered questionnaire with a larger sample of community residents. Most individuals had knowledge of scabies and were aware that person to person transmission occurred. However personal and environmental hygiene were both incorrectly identified as particularly important in the transmission of scabies. Cost played a major role in determining where individuals sought care and both poverty and disease associated stigma resulted in delays seeking care. There is a need to improve community and health care worker education about scabies and improve affordable access to treatment.

epidemiology↗

bioRxiv2018

Comprehensive analysis of human hookworm secreted proteins using a proteogenomic approach

The human hookworm Necator americanus infects more than 400 million people worldwide, contributing substantially to the poverty in these regions. Adult stage N. americanus live in the small intestine of the human host where they inject excretory/secretory (ES) products into the mucosa. ES products have been characterized at the proteome level for a number of animal hookworm species, but until now, the difficulty in obtaining sufficient live N. americanus has been an obstacle in characterizing the secretome of this important human pathogen. Herein we describe the ES proteome of N. americanus and utilize this information to conduct the first proteogenomic analysis of a parasitic helminth, significantly improving the available genome and thereby generating a robust description of the parasite secretome. The genome annotation resulted in a a revised prediction of 3,425 fewer genes than initially reported, accompanied by a significant increase in the number of exons and introns, total gene length and the percentage of the genome covered by genes. Almost 200 ES proteins were identified by LC-MS/MS with SCP/TAPS proteins, hypothetical proteins and proteases among the most abundant families. These proteins were compared to commonly used model species of human parasitic infections, including Ancylostoma caninum, Nippostrongylus brasiliensis and Heligmosomoides polygyrus. Our findings provide valuable information on important families of proteins with both known and unknown functions that could be instrumental in host-parasite interactions, including protein families that might be key for parasite survival in the onslaught of robust immune responses, as well as vaccine and drug targets.

microbiology↗