Biology subjects

Diallo, A. B.

Publications and source records attributed to Diallo, A. B..

12 recordsLinked to original sources

bioRxiv2026

Validation of behavioural tests for personality assessment in tie-stall dairy cows

The study of animal personality has gained increasing attention in recent years, as researchers recognize that non-human animals exhibit stable individual differences in behaviour. In dairy cattle, understanding personality traits holds potential for improving animal welfare, enhancing management practices, and supporting productivity outcomes. However, validating the behavioural tests used to assess these traits remains a significant challenge. The present study aimed to evaluate the consistency and validity of five commonly used behavioural tests in dairy cows: the Human Approach Test (HAT), Sudden Test (SUD), Novel Object Test (NOT), Open Field Test (OFT), and Novel Surface Test (NST). These tests were chosen for their potential to assess personality dimensions that parallel components of human personality, particularly Openness, Neuroticism, Extraversion, and Agreeableness. Repeated assessments were conducted across three time periods to evaluate both intra-test (temporal) and inter-test (contextual) consistency. Results revealed that only the SUD exhibited significant behavioural consistency across all periods, suggesting its potential as a reliable tool for personality assessment. Additionally, a moderate correlation between the HAT and SUD was observed, indicating that these tests may capture overlapping personality traits. In contrast, the remaining tests (NOT, OFT, NST) lacked consistent behavioural patterns over time and across contexts, raising questions about their reliability and the complexity of trait expression. These findings highlight the challenges of identifying stable personality traits in cattle and emphasize the need for more rigorous validation of behavioural tests. This research contributes to the growing field of animal personality by providing insights into trait stability, the limitations of current testing methods, and the potential application of personality assessment in future livestock management practices.

animal behavior and cognition↗

bioRxiv2026

Investigating cognitive enrichment for dairy calves through behavioral measures of participation and engagement: a pilot study

Introducing cognitive enrichment from an early age has the potential to enhance an animals capacity to learn both simple and complex tasks, promote neural plasticity, and support cognitive development. This is applicable for young cattle who are at a critical stage in their development and could benefit from the influence cognitive enrichment has on their behavioral expression. This study aims to explore the effects cognitive enrichment has on weaned dairy calves through analyzing behavioral measures of voluntary participation and short-term behavioral reactions to enrichment exposure. Our study involved a total of five pairs of weaned calves (n=8 treatment; n=2 control). The treatment groups were presented with three variations of a puzzle box, each equipped with unique challenges that offer different solutions (push, slide, pull). These boxes were provided to the calves twice daily over the span of nine days in an isolated corridor located behind their pen. We hypothesized that motivated calves would consistently engage with cognitive enrichment voluntarily over time and express directed natural behaviors, reflecting sustained participation across repeated trials. Results demonstrated that calves consistently visited the cognitive enrichment area across trials, with an average latency of 75.7 {+/-} 47.0s from the pen to the enrichment. Secondly, the calves spent a significant proportion of trial time within the enrichment area at 65% (870.1 {+/-} 21s). Lastly, all calves expressed a broad range of behaviors in line with their natural exploration within the enrichment area, while the puzzle box treatment groups expressed higher durations of behavioral expressions when compared to the control (F=11.7, p<0.0001). Combined, these results indicate the calves motivations to voluntarily participate in a cognitive challenge. While these are promising findings for cognitive enrichment and its applicability to dairy calves, further work is needed to understand broader parameters. Specifically, how can social dynamics influence enrichment interaction in groups, how can this type of enrichment be implemented on farms, and what are the long-term effects to providing cognitive enrichment in the early stages of development.

zoology↗

bioRxiv2026

Responses of dairy cows following a change in housing system and social group: a living lab experiment

To investigate how the disturbances associated with a relocation to a bedded-pack barn, such as a housing system change, a milking system change and a social regrouping, impacts the behavior of lactating dairy cows, 38 cows from a total of 9 tie-stall or free-stall commercial farms were moved to a newly built bedded-pack barn on an enrollment basis, with a social regrouping occurring after 2 weeks. Scan sampling of video data was done to assess behavior expression in the pen, and live data was collected to assess milking reactivity and animal handling procedures. Results indicate that the cows adapted quickly to the relocation to the new housing system as there were no changes in the locations in the pen, the body positions or the behaviors of cows in time between arrival and regrouping. The social regrouping had a bigger impact with a decrease in 16% of the observed time spent lying and an increase of 9.7% of the observed time spent feeding. Cows also adapted quickly to the milking procedures with a rapid decrease in the occurrence of negative social interactions between cows at the parlor, and in needing less human-animal manipulations and less time to be brought to the parlor. The housing system of origin had a slight effect on behaviors with cows from tie-stalls spending 1.7 times more of the observed time lying than free-stall cows, and free-stall cows spending 1.6 times more of the observed time feeding than tie-stall cows. This study provides a better understanding of how dairy cows respond to disturbances and is encouraging for producers that need to make changes to their current housing system as cows were shown to be quickly adaptable to the challenges presented to them. SummaryDairy cows from cubicle systems were shown to adapt quickly after a relocation to a bedded pack barn, the first use of a milking parlor, and a social regrouping. This was supported by limited changes observed in their behaviors after the disturbances, and observed deviations were temporary and short-lived. Animal handling procedures also observed a quick improvement in time with the trips to the milking parlor needing 2x less time and 3.5x fewer physical contacts from handlers after 5 days. These results are encouraging to producers needing to make changes to their barns.

zoology↗

bioRxiv2026

Discovering subclinical effects of limited outdoor access on gait and hoof health of cows housed in movement-restricted environments

Most common housing systems for dairy cows restrict their movement, which can influence welfare, gait, and hoof health of dairy cows. Outdoor access has been proposed as a management practice to offset these restrictions, but reported effects on cows locomotion vary and may not always be captured by traditional clinical assessments. In this study, we investigated gait and hoof through clinical (i.e., visual locomotion scoring and hoof lesion assessment) and subclinical (3D motion analysis, kinetic assessment, hoof infrared thermography and measuring claw conformation) methods to assess how limited provision of outdoor access affects non-lame cows housed in movement restricted environment. Thirty-six Holstein tie-stall cows were either given 1day/week (EX1) or 3days/week (EX3) of outdoor access (1h/day) during 5 consecutive weeks. Clinical and subclinical assessments of gait and hoof were performed before (Pre-trial), after 5 weeks of outing (Post-trial) and 8 weeks after outing (Follow-up). The results of this study revealed no clinical effect of outdoor access on cows locomotion score and hoof lesion prevalence. However, for subclinical assessment, both groups showed an increase in stride and stance time at Post-trial, with an increase in pressure applied by cows while standing in EX3 group and a reduction in coronary band temperature in both groups at Post-trial and Follow-up. Contact area and claw conformation changed after provision of outdoor access in both groups. This study illustrates that with the use of subclinical methods; we can reveal effects of outdoor access on gait and hoof health that might not be visible using the traditional methods.

zoology↗

bioRxiv2025

High-Resolution Characterization of rAAV Genomes for Vector Quality Using Long-Read Sequencing

Recombinant adeno-associated virus (rAAV)-mediated gene therapy has been applied for human diseases. However, the rAAV capsids contain heterogeneous mixtures of full-length and truncated genomes and, depending on the manufacturing process, residual host cell and plasmid DNA. Therefore, a method is needed to characterize the encapsidated DNA of rAAV in order to support process development and batch release. The emerging long-read sequencing (LRS) has achieved AAV single-genome resolution. Here we propose a Python-based LRS profiling framework to classify and quantitate residual DNA species in rAAV products. We designed a reference that contains universal genetic components that are commonly used in rAAV production, including AmpR, KanR, Rep and Cap genes along with HPV18, Ad5 and hg38 genomes. We accessed the impurities of rAAV production from public and in-house LRS datasets. Analyzing the lambda fragments supplemented in these datasets showed that sequencing introduced size biases, which couldnt be fully corrected by regression but is improvable within library preparation. Functional potential of impurities were assessed through indicators derived from long-read alignments, which enabled us to quantitatively compare impurities between manufacturing batches. We demonstrated that LRS provides informative metrics for rAAV production and can facilitate process development to ensure therapeutic product safety and quality.

genomics↗

bioRxiv2021

Integration of Diverse Transcriptomics Datasets using Random Forest to Predict Universal Functional Pathways in Tfr Cells

MotivationT follicular regulatory (Tfr) cells are a specialized cell subset that controls humoral immunity. Despite a number of individual transcriptomic studies on these cells, core functional pathways have been difficult to uncover due to the substantial transcriptional overlap of these cells with other effector cell types, as well as transcriptional changes occurring due to disease settings. Developing a core transcriptional module for Tfr cells that integrates multiple cell type comparisons as well as diverse disease settings will allow a more accurate prediction of functional pathways. Researchers studying allergic reactions, immune responses to vaccines, autoimmunity and cancer could use this gene set to better understand the roles of Tfr cells in controlling disease progression. Additional cell types beyond Tfr cells that have similar features of transcriptomic complexity within diverse disease settings may also be studied using similar approaches. High-throughput sequencing technologies allow the generation of large datasets that require specific tools to best interpret the data. The development of a core transcriptional module for Tfr cells will allow investigators to determine if Tfr cells may have functional roles within their biological systems with little knowledge of Tfr biology. With this work, we have addressed the need of core gene modules to define specific subsets of immune cells. ResultsWe introduce an integrated "core Tfr cell gene module" that can be incorporated into GSEA analysis using various input sizes. The integrated core Tfr gene module was built using transcriptomic studies in Tfr cells from several different tissues, disease settings, and cell type comparisons. Random forest was used to integrate the transcriptomic studies to generate the core gene module. A GSEA gene set was formulated from the integrated core Tfr gene module for incorporation into end-user friendly GSEA. The gene sets are presented along with random genes taken from the GTEX data set and are presented as GMT files. The user can upload the gene set to the GSEA website or any gene set tool which takes GMT files. We also present the full results of the model including p-values calculated by random forest. This provides users with more flexibility in choosing a p-value cutoff that is most appropriate for the experimental setting. AvailabilityThe core Tfr gene sets are freely available at: https://github.com/alosdiallo/TFR_Model. We have also included all of the code and data used in developing these gene sets. The code and results are released under an MIT license. Supplementary informationSupplementary data are available at Bioinformatics online.

bioinformatics↗

bioRxiv2020

Monocytes and macrophages, targets of SARS-CoV-2: the clue for Covid-19 immunoparalysis

To date, the Covid-19 pandemic affected more than 18 million individuals and caused more than 690, 000 deaths. Its clinical expression is pleiomorphic and severity is related to age and comorbidities such as diabetes and hypertension. The pathophysiology of the disease relies on aberrant activation of immune system and lymphopenia that has been recognized as a prognosis marker. We wondered if the myeloid compartment was affected in Covid-19 and if monocytes and macrophages could be infected by SARS-CoV-2. We show here that SARS-CoV-2 efficiently infects monocytes and macrophages without any cytopathic effect. Infection was associated with the secretion of immunoregulatory cytokines (IL-6, IL-10, TGF-{beta}) and the induction of a macrophagic specific transcriptional program characterized by the upregulation of M2-type molecules. In addition, we found that in vitro macrophage polarization did not account for the permissivity to SARS-CoV-2, since M1-and M2-type macrophages were similarly infected. Finally, in a cohort of 76 Covid-19 patients ranging from mild to severe clinical expression, all circulating monocyte subsets were decreased, likely related to massive emigration into tissues. Monocytes from Covid-19 patients exhibited decreased expression of HLA-DR and increased expression of CD163, irrespective of the clinical status. Hence, SARS-CoV-2 drives circulating monocytes and macrophages inducing immunoparalysis of the host for the benefit of Covid-19 disease progression.

immunology↗

bioRxiv2020

Daytime variation in SARS-CoV-2 infection and cytokine production

S. Ray and A. Reddy recently anticipated the implication of circadian rhythm in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of the coronavirus disease (Covid-19). In addition to its key role in the regulation of biological functions, the circadian rhythm has been suggested as a regulator of viral infections. Specifically, the time of day of infection was found critical for illness progression, as has been reported for influenza, respiratory syncytial and parainfluenza type 3 viruses. We analyzed circadian rhythm implication in SARS-CoV-2 virus infection of isolated human monocytes, key actor cells in Covid-19 disease, from healthy subjects. The circadian gene expression of Bmal1 and Clock genes was investigated with q-RTPCR. Monocytes were infected with SARS-CoV-2 virus strain and viral infection was investigated by One-Step qRT-PCR and immunofluorescence. Interleukin (IL)-6, IL-1{beta} and IL-10 levels were also measured in supernatants of infected monocytes. Using Cosinor analysis, we showed that Bmal1 and Clock transcripts exhibited circadian rhythm in monocytes with an acrophase and a bathyphase at Zeitgeber Time (ZT)6 and ZT17. After forty-eight hours, the amount of SARS-CoV-2 virus increased in the monocyte infected at ZT6 compared to ZT17. The high virus amount at ZT6 was associated with significant increased release in IL-6, IL-1{beta} and IL-10 compared to ZT17. Our results suggest that time day of SARS-CoV-2 infection affects viral infection and host immune response. They support consideration of circadian rhythm in SARS-CoV-2 disease progression and we propose circadian rhythm as a novel target for managing viral progression. ImportanceThe implication of circadian rhythm (CR) in pathogenesis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been recently anticipated. The time of day of infection is critical for illness progression as reported for influenza, respiratory syncytial and parainfluenza type 3 viruses. In this study, we wondered if SARS-CoV-2 infection and cytokine production by human monocytes, innate immune cells affected by Covid-19, were regulated by CR. Our results suggest that time day of SARS-CoV-2 infection affects viral infection and host immune response. They support consideration of circadian rhythm in SARS-CoV-2 disease progression and we propose circadian rhythm as a novel target for managing viral progression.

immunology↗

bioRxiv2019

Revisiting the landscape of evolutionary breakpoints across human genome using multi-way comparison

Genome rearrangement is one of the major forces driving the processes of the evolution and disease development. The chromosomal position affected by these rearrangements are called breakpoints. The breakpoints occurring during the evolution of species are known to be non randomly distributed. Detecting their landscape and mapping them to genomic features constitute an important features in both comparative and functional genomics. Several studies have attempted to provide such mapping based on pairwise comparison of genes as conservation anchors. With the availability of more accurate multi-way alignments, we design an approach to identify synteny blocks and evolutionary breakpoints based on UCSC 45-way conservation sequence alignments with 12 selected species. The multi-way designed approach with the mild flexibility of presence of selected species, helped to have a better determination of human lineage-specific evolutionary breakpoints. We identified 261,391 human lineage-specific evolutionary breakpoints across the genome and 2,564 dense regions enriched with biological processes involved in adaptive traits such as response to DNA damage stimulus, cellular response to stress and metabolic process. Moreover, we found 230 regions refractory to evolutionary breakpoints that carry genes associated with crucial developmental process such as organ morphogenesis, skeletal system development, chordate embryonic development, nerve development and regulation of biological process. This initial map of the human genome will help to gain better insight into several studies including developmental studies and cancer rearrangement processes.

genomics↗

bioRxiv2016

CASTOR: A machine learning platform for reproducible viral genome classification

MotivationAdvances in cloning and sequencing technology yielded a massive number of genome of virus strains. The classification and annotation of these genomes constitute important assets in the discovery of genomic variability, taxonomic characteristics and disease mechanisms. Existing classification methods are often designed for a well-studied virus. Thus, the viral comparative genomic studies could benefit from more generic, fast and accurate tools for classifying and typing newly sequenced strains of diverse virus families.\n\nResultsHere, we introduce a fast, accurate and generic virus classification platform, CASTOR, based on a machine learning approach. CASTOR is inspired by a well-known technique in molecular biology: Restriction Fragment Length Polymorphism (RFLP). It simulates the restriction digestion of genomic material by different enzymes into fragments in-silico. It uses two metrics to construct feature vectors for machine learning algorithms in the classification step. We benchmark CASTOR for the classification of distinct datasets of Human Papillomaviruses (HPV), Hepatitis B Viruses (HBV) and Human Immunodeficiency viruses (HIV). Results reveal true positive rates of 99%, 99% and 98% for HPV Alpha species, HBV genotyping and HIV M group subtyping respectively. Furthermore, CASTOR shows a competitive performance compare to well-known HIV-specific classifier REGA and COMET on whole genome and pol fragments. With such prediction rates, genericity and robustness, as well as rapidity, such approach could constitute a reference in large-scale virus studies. Finally, we developed the CASTOR web platform for open access and reproducible viral machine learning classifiers.\n\nAvailabilityhttp://castor.bioinfo.uqam.ca\n\nContactdiallo.abdoulaye@uqam.ca

bioinformatics↗

bioRxiv2016

Towards an ontology-based recommender system for relevant bioinformatics workflows

BackgroundWith the large and diverse type of biological data, bioinformatic solutions are being more complex and computationally intensive. New specialized data skills need to be acquired by researchers in order to follow this development. Workflow Management Systems rise as an efficient way to automate tasks through abstract models in order to assist users during their problem solving tasks. However, current solutions could have several problems in reusing the developed models for given tasks. The large amount of heterogenous data and the lack of knowledge in using bioinformatics tools could mislead the users during their analyses. To tackle this issue, we propose an ontology-based workflow-mining framework generating semantic models of bioinformatic best practices in order to assist scientists. To this end, concrete workflows are extracted from scientific articles and then mined using a rich domain ontology.\n\nResultsIn this study, we explore the specific topics of phylogenetic analyses. We annotated more than 300 recent articles using different ontological concepts and relations. Relative supports (frequencies) of discovered workflow components in texts show interesting results of relevant resources currently used in the different phylogenetic analysis steps. Mining concrete workflows from texts lead us to discover abstract but relevant patterns of the best combinations of tools, parameters and input data for specific phylogenetic problems.\n\nConclusionsExtracted patterns would make workflows more intuitive and easy to be reused in similar situations. This could provide a stepping-stone into the identification of best practices and pave the road to a recommender system.

bioinformatics↗

bioRxiv2016

Ontology-based workflow extraction from texts using word sense disambiguation

This paper introduces a method for automatic workflow extraction from texts using Process-Oriented Case-Based Reasoning (POCBR). While the current workflow management systems implement mostly different complicated graphical tasks based on advanced distributed solutions (e.g. cloud computing and grid computation), workflow knowledge acquisition from texts using case-based reasoning represents more expressive and semantic cases representations. We propose in this context, an ontology-based workflow extraction framework to acquire processual knowledge from texts. Our methodology extends classic NLP techniques to extract and disambiguate tasks in texts. Using a graph-based representation of workflows and a domain ontology, our extraction process uses a context-based approach to recognize workflow components : data and control flows. We applied our framework in a technical domain in bioinformatics : i.e. phylogenetic analyses. An evaluation based on workflow semantic similarities on a gold standard proves that our approach provides promising results in the process extraction domain. Both data and implementation of our framework are available in : http://labo.bioinfo.uqam.ca/tgrowler.

bioinformatics↗