Biology subjects

Henry, D.

Publications and source records attributed to Henry, D..

6 recordsLinked to original sources

bioRxiv2025

Robust design and validation of LAMP assays for in-field detection of three major bacterial vascular diseases of banana

Bacterial diseases of banana are becoming increasingly significant worldwide, resulting in reduced yields and higher disease management costs. The most important bacterial diseases of banana include Moko and banana blood disease (BBD), caused by Ralstonia solanacearum and Ralstonia syzygii subsp. celebesensis, respectively, and banana Xanthomonas wilt (BXW) caused by Xanthomonas vasicola pv. musacearum. Effective surveillance and disease management require point-of-care diagnostics, such as loop-mediated isothermal amplification (LAMP), for on-site operation. In this study, three LAMP assays were developed to specifically detect the bacteria responsible for Moko, BBD and BXW, directly from banana tissues, using a simplified DNA extraction protocol. The BBD - and BXW-LAMP assays demonstrated 100% specificity, yielding negative results for a broad range of non-target bacteria, including closely related species as well as pathogenic and endophytic strains associated with banana, and positive results for all the tested target strains. For Moko disease, a duplex-LAMP assay was developed to detect all strains from the four globally most relevant sequevars: IIB-3, IIB-4, IIA-6, and IIA-24. The duplex-LAMP successfully detected all target strains, except one that was shown to be non-pathogenic to Cavendish bananas. All non-target strains tested negative, with the exception of a delayed signal for one strain belonging to Ralstonia thomasi, not associated with banana environment (hospital strain). These results were supported by an extensive in silico analysis conducted on 9,668 Burkholderiaceae and 7,483 Xanthomonadaceae genomes. Detection limits ranged from 0.1 pg/{micro}l to 1 pg/{micro}l DNA, and from 10 to 10 CFU/ml on banana tissues spiked with calibrated bacterial suspensions, depending on the assay. The LAMP assays prove highly effective for detecting target pathogens in both artificially inoculated banana plants and field samples, offering a promising tool for improving disease management strategies.

molecular biology↗

bioRxiv2025

A dual mechanism of sensitivity to PLK4 inhibition by RP-1664 in neuroblastoma

A novel therapeutic strategy was recently proposed for high-risk neuroblastoma carrying copy number gain of the TRIM37 gene: centriole loss upon inhibition of polo-like kinase 4 (PLK4), while tolerated by normal cells, induces aberrant mitotic spindle formation and p53-dependent cell death in TRIM37-overexpressing cells. Interestingly, while full PLK4 inhibition causes centriole loss, partial inhibition is known to elevate centriole numbers. Here we show using a novel selective PLK4 inhibitor RP-1664 that both centriole loss and amplification contribute to hypersensitivity of neuroblastoma cells. Whereas inactivation of TRIM37 and TP53 rescues neuroblastoma cell death at higher concentrations of RP-1664, at lower doses cell death is TRIM37/TP53-independent. With CRISPR screens and live cell imaging we demonstrate that upon centriole amplification, neuroblastoma cells succumb to multipolar mitoses due to inability to cluster or inactivate supernumerary centrosomes. In vivo, RP-1664 shows robust efficacy in neuroblastoma xenografts at doses consistent with centriole amplification. STATEMENT OF SIGNIFICANCEHigh-risk neuroblastoma is associated with poor outcomes in pediatric patients and novel therapies need to be developed. We show that neuroblastoma cells are remarkably sensitive to PLK4 inhibitors due to a combination of two complementary mechanisms, supporting the evaluation of PLK4 inhibitors in clinical trials of high-risk neuroblastoma.

cancer biology↗

bioRxiv2023

Role of Ribeye PXDLS/T-binding cleft in normal synaptic ribbon function

Non-spiking sensory hair cells of the auditory and vestibular systems encode a dynamic range of graded signals with high fidelity by vesicle exocytosis at ribbon synapses. Ribeye, the most abundant protein in the synaptic ribbon, is composed of a unique A domain specific for ribbons and a B-domain nearly identical to the transcriptional corepressor CtBP2. CTBP2 and the B-domain of Ribeye contain a surface cleft that binds to proteins harboring a PXDLS/T peptide motif. Little is known about the importance of this binding site in synaptic function. Piccolo has a well-conserved PVDLT motif and we find that overexpressed Ribeye exhibits striking co-localization with Piccolo in INS-cells, while two separate mutants containing mutations in PXDLS/T-binding region, fail to co-localize with Piccolo. Similarly, co-transfected Ribeye and a piccolo fragment containing the PVDLT region co-localize in HEK cells. Expression of wild-type Ribeye-YFP in zebrafish neuromast hair cells returns electron densities to ribbon structures and mostly rescued normal synaptic transmission and morphological phenotypes in a mutant zebrafish lacking most Ribeye. By contrast, Ribeye-YFP harboring a mutation in the PXDLS/T-binding cleft resulted in ectopic electron dense aggregates that did not collect vesicles and the persistence of ribbons lacking electron densities. Furthermore, overexpression failed to return capacitance responses to normal levels. These results point toward a role for the PXDLS/T-binding cleft in the recruitment of Ribeye to ribbons and in normal synaptic function. Significance statementHair cell synaptic ribbons are evolutionarily conserved structures that appear dense in electron micrographs, extend from the release site into the cytoplasm and tether synaptic vesicles for release. Here, we show that Ribeye, the major component of the synaptic ribbon electron density is directed to ribbons via its PXDLS/T-binding site and that mutant isoforms of Ribeye with point mutations disrupting these interactions fail to rescue normal function in mutant zebrafish lacking most Ribeye.

neuroscience↗

bioRxiv2022

Automated detection of sow posture changes with millimeter-wave radars and deep learning

Automated behavioural monitoring is increasingly required for animal welfare and precision agriculture. In pig farming, detailed analyses of sow activity are essential to identify and reduce the risks of piglets being crushed during postural changes of their mothers. Here we introduce a new, non-invasive, fast and accurate method for monitoring sow behaviour based on millimeter-wave radars and deep learning analysis. We used our method to predict postural changes in crated sows and distinguish the dangerous one that lie down abruptly from those that lie down carefully using transient postures. Two radars were placed on a metal backing above the head and the upper part of the back of each of ten sows to monitor their activity during 5 hours. We analysed the radar data with a convolutional neural network and identified five postures. The average sensitivity was 96.9% for standing, 90.8% for lying, 91.4% for nursing, 87.6% for sitting, but only 11.9% for kneeling. However, the average specificity and accuracy were greater than 92% for the five postures. Interestingly, two of the ten sows occasionally moved directly from standing to lying, without using the transient postures sitting and kneeling, thereby displaying risky behaviours for their piglets. Our radar-based classifier is more accurate, faster and require less memory than current computer vision approaches. Using more sows will improve the algorithm performance and facilitate future applications for large scale deployment in animal farming. HighlightsO_LIAutomated behavioural analysis is a major challenge for precision farming. C_LIO_LIWe developed automated detection of lactating sow postures with radars and deep learning. C_LIO_LIWe identified five postures, including transitions risky for the piglets. C_LIO_LIOur method is accurate, fast and requires less memory than computer vision. C_LIO_LIRadars thus hold considerable promises for high through-put recording of livestock activity. C_LI

animal behavior and cognition↗

bioRxiv2020

A non-invasive radar system for automated behavioural tracking: application to sheep

Automated quantification of the behaviour of freely moving animals is increasingly needed in ethology, ecology, genetics and evolution. State-of-the-art approaches often require tags to identify animals, high computational power for data collection and processing, and are sensitive to environmental conditions, which limits their large-scale utilisation. Here we introduce a new automated tracking system based on millimetre-wave radars for real time robust and high precision monitoring of untagged animals. To validate our system, we tracked 64 sheep in a standard indoor behavioural test used for genetic selection. First, we show that the proposed radar application is faster and more accurate than conventional video and infrared tracking systems. Next, we illustrate how new behavioural estimators can be derived from the radar data to assess personality traits in sheep for behavioural phenotyping. Finally, we demonstrate that radars can be used for movement tracking at larger spatial scales, in the field, by adjusting operating frequency and radiated electromagnetic power. Millimetre-wave radars thus hold considerable promises for high-throughput recording of the behaviour of animals with various sizes and locomotor modes, in different types of environments.

animal behavior and cognition↗

bioRxiv2020

Expression and distribution of synaptotagmin isoforms in the zebrafish retina

Synaptotagmins belong to a large family of proteins. While various synaptotagmins have been implicated as Ca2+ sensors for vesicle replenishment and release at conventional synapses, their roles at retinal ribbon synapses remain incompletely understood. Zebrafish is a widely used experimental model for retinal research. We therefore investigated the homology between human, rat, mouse, and zebrafish synaptotagmins 1 to 10 using a bioinformatics approach. We also characterized the expression and distribution of various synaptotagmin (syt) genes in the zebrafish retina, using RT-PCR and in situ hybridization, focusing on the family members whose products likely underlie Ca2+-dependent exocytosis in the central nervous system (synaptotagmins 1, 2, 5 and 7). We find that most zebrafish synaptotagmins are well conserved and can be grouped in the same classes as mammalian synaptotagmins, based on crucial amino acid residues needed for coordinating Ca2+ binding and determining phospholipid binding affinity. The only exception is synaptotagmin 1b, which lacks 34 amino acid residues in the C2B domain and is therefore unlikely to bind Ca2+ there. Additionally, the products of zebrafish syt5a and syt5b genes share identity with mammalian class 1 and class 5 synaptotagmins. Zebrafish syt1, syt2, syt5 and syt7 paralogues are found in the zebrafish brain, eye, and retina, excepting syt1b, which is only present in the brain. The complementary expression pattern of the remaining paralogues in the retina suggests that syt1a and syt5a may underlie synchronous release and syt7a and syt7b may mediate asynchronous release or other Ca2+ dependent processes in different types of retinal neurons.

neuroscience↗