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Jacobs, L.

Publications and source records attributed to Jacobs, L..

9 recordsLinked to original sources

A Cell Viability and Utility Index (CVUI) for wildlife fibroblast biobanking: framework development and preliminary empirical validation

Wildlife biobanking depends on consistent, reproducible cell culture outcomes, yet no standardised framework exists for assessing culture quality across taxa or for integrating quality metrics into institutional collections management systems. Here, we present the Cell Viability and Utility Index (CVUI), a scored pipeline framework validated in a pilot study of 154 culture rounds from 46 species held in the Ian Potter Australian Wildlife Biobank at Museums Victoria Research Institute. The CVUI was adapted from the Wildlife Sperm Index (Jacobs et al., 2026) and assigns weighted scores encompassing four sequential culture stages -- establishment, first passage, expansion, and cryobanking -- with a continuous viability modifier applied at the cryobanking stage. Survival analysis identified individual animal identity as the primary source of variance in culture establishment, whereas taxon was the primary predictor of first-passage success. Beyond first passage, failure rates were too low to reliably assess either effect, with critical attrition concentrated at the earliest pipeline stages. These findings informed the differential weighting of CVUI components and have direct implications for workflow prioritisation and banking strategy. Monitoring can now be targeted at establishment and first passage, the stages where intervention has the greatest impact, with taxon-specific attention warranted at first passage and individual-level attention at establishment, while the robustness of the late-stage protocol means that banking yield is largely determined before a culture reaches P1. Integration of CVUI scores into collections management platforms such as Axiell EMu (Electronic Museum) would transform passive record-keeping into active decision support, enabling real-time quality tracking, early flagging of at-risk cultures, and longitudinal benchmarking of biobank performance across species, collectors, and tissue types. This framework provides a foundation for optimising wildlife fibroblast biobanking protocols, developing taxon-specific culture standards, and expanding standardised quality assessment across wildlife biobanks nationally and internationally.

zoology↗

Hormonal and Environmental Drivers of Spermiation in the Endangered Mountain Yellow-Legged Frog (Rana muscosa): Toward Biologically Informed Assisted Reproductive Technologies.

Amphibians are among the most threatened vertebrates, yet assisted reproductive technologies (ARTs) remain underutilised in their conservation. We developed and evaluated a biologically relevant, non-lethal sperm collection protocol for Rana muscosa, a critically endangered frog in a long-term conservation breeding program. Thirteen hormone treatments were tested across six post-injection time points, and sperm quality was assessed via concentration, motility, osmolality, and pH. Generalised linear mixed models revealed that gonadotropin-releasing hormone (GnRHa) alone significantly outperformed hCG-based regimens. The 3 {micro}g/g GnRHa dose yielded the highest sperm concentration and sustained motility from 3 to 24 hours post-injection. Motility was highest under moderately acidic (pH 6.5-7.0) and hypoosmotic (75-100 mOsm/kg) conditions. To support decision-making, we applied a refined Wildlife Sperm Index (WSI) that weights motility and concentration as primary functional-yield traits, with motility given greater relative weight given its direct role in fertilisation, and treats pH and osmolality as secondary environmental-compatibility traits. Under this revised composite score, 3 {micro}g/g GnRHa achieved the highest overall WSI score, outperforming 2 {micro}g/g and 4 {micro}g/g GnRHa, which ranked second and third, respectively, despite their more favourable pH and osmolality profiles. These findings provide the first evidence-based ART protocol for R. muscosa and offer a transferable framework for optimising gamete collection, IVF, and cryopreservation in line with other amphibian species, advancing both genetic management and species recovery goals.

zoology↗

One Number to Rule Them All: The Wildlife Sperm Index for Standardized Gamete Assessment

In wildlife conservation, breeding programs focused on reintroduction are critical to recovering endangered species. Assisted reproductive technologies (ARTs) and biobanking play pivotal roles in these efforts but depend on high-quality gametes. Spermatozoa, due to their structural simplicity and well documented quality assessments are often considered the preferred cell type for cryopreservation and ARTs, especially in rare or exotic species. However, inconsistent retrieval of sperm samples with sufficient volume and concentration, especially for critically endangered species, can pose major limitations to assessing overall sperm quality. To address this information gap, we have developed the Wildlife Sperm Index (WSI), a standardized scoring system that integrates key sperm quality metrics--such as motility, viability, and DNA integrity--into a weighted composite score. While this study applies the WSI to sperm, the framework is adaptable to other cell types used in biobanking and reproductive technologies, broadening its potential utility. Unlike traditional sperm assessments that rely solely on microscopy, the WSI provides a scalable and quantitative framework for evaluating samples across species, including those that yield low-volume or concentration sperm samples. We validated the WSI against traditional means of sperm quality assessments, demonstrating its reliability as both a quality assessment and decision-making tool, enabling users to evaluate sample suitability for cryopreservation, ARTs, or downstream applications. By enabling standardized quality tracking, the WSI provides a foundation for more informed reproductive decisions to support global conservation efforts. Summary sentenceWe present the Wildlife Sperm Index (WSI), a standardized, composite scoring system that integrates key sperm quality metrics to improve gamete assessment and supports assisted reproduction and biobanking in wildlife conservation.

cell biology↗

Redox-dependent synaptic clustering of gephyrin

Reactive oxygen species (ROS) play a central role in enhancing inhibitory signal transmission, thus extending their role beyond oxidative stress in disease and aging. However, the underlying molecular mechanisms mediating these functions have remained elusive. At inhibitory synapses, the scaffolding protein gephyrin clusters glycine and GABA type A receptors. Since gephyrin harbors multiple surface-exposed cysteines, we investigated the regulatory influence of ROS on gephyrin. We show that H2O2-induced oxidation of gephyrin cysteines triggered reversible, synaptic multimerization through disulfide bridge formation, which provided more receptor binding sites, lead to proteolytic protection and enhanced liquid-liquid phase separation. We identified mitochondria-derived ROS as a physiological source and observed oxidized gephyrin multimers in vivo, indicating that gephyrin can be regulated by the redox environment. Collectively, our findings suggest that cysteines in gephyrin modulate synaptic localization and clustering as regulatory redox-switches thereby establishing a link between neuronal and mitochondrial activity.

neuroscience↗

The NAPstar family of NADP redox state sensors highlights glutathione as the primary mediator of anti-oxidative electron flux

The NADPH/NADP+ redox couple is central to metabolism and redox signalling. NADP redox state is differentially regulated by distinct enzymatic machineries at the subcellular compartment level. Nonetheless, a detailed understanding of subcellular NADP redox dynamics is limited by the availability of appropriate tools. Here, we introduce NAPstars, a family of genetically encoded, fluorescent protein-based NADP redox state biosensors. NAPstars offer real-time, specific, pH-resistant measurements, across a broad-range of NADP redox states, with subcellular resolution. We establish NAPstar measurements in yeast, plants and mammalian cell models, revealing a conserved robustness of cytosolic NADP redox homeostasis. NAPstars uncovered NADP redox oscillations linked to the cell cycle in yeast and illumination- and hypoxia-dependent NADP redox changes in plant leaves. By selectively impairing the glutathione and thioredoxin anti-oxidative pathways under acute oxidative challenge, NAPstars demonstrated an unexpected role for the glutathione system as the primary mediator of anti-oxidative electron flux that is conserved across eukaryotic kingdoms.

biochemistry↗

Pharmacological validation of an attention bias test for conventional broiler chickens

Fear and anxiety are considered concerns for animal welfare as they are associated with negative affective states. This study aimed to pharmacologically validate an attention bias test (ABT) for broiler chickens (Gallus gallus domesticus) as a cognitive bias test to determine anxiety. Two-hundred-and-four male Ross 708 broiler chickens were arbitrarily allocated to either the anxiogenic or control treatment at day 25 of age, resulting in 102 birds per treatment. Birds from the anxiogenic group were administered with 2.5 mg/kg of {beta}-CCM ({beta}-carboline-3-carboxylic acid-N-methylamide [FG 7142]) through an intraperitoneal injection at a volume of 0.1 ml/100 g of body weight. Birds from the control group were administered with 9 mg/kg of a saline solution. During ABT, birds were tested in groups of three (n = 34 groups of three birds/treatment) with commercial feed and mealworms as positive stimuli and a conspecific alarm call as a negative stimulus. Control birds were 45 s faster to begin feeding than anxiogenic birds. Birds from the control group vocalized 40 s later and stepped 57 s later than birds from the anxiogenic group. The occurrence of vigilance behaviors did not differ between treatments. This study was successful in pharmacologically validating an attention bias test for fast-growing broiler chickens, testing three birds simultaneously. Our findings showed that latencies to begin feeding, first vocalization, and first step were valid measures to quantify anxiety.

animal behavior and cognition↗

Harnessing Bilayer Biomaterial Delivery of FTY720 as an Immunotherapy to Accelerate Oral Wound Healing

Orofacial clefts are the most common craniofacial congenital anomaly. Following cleft palate repair, up to 60% of surgeries have wound healing complications leading to oronasal fistula (ONF), a persistent connection between the roof of the mouth and the nasal cavity. The current gold standard methods for ONF repair use human allograft tissues; however, these procedures have risks of graft infection and/or rejection, requiring surgical revisions. Immunoregenerative therapies present a novel alternative approach to harness the bodys immune response and enhance the wound healing environment. We utilized a repurposed FDA-approved immunomodulatory drug, FTY720, to reduce the egress of lymphocytes and induce immune cell fate switching toward pro-regenerative phenotypes. Here, we engineered a bilayer biomaterial system using Tegaderm, a liquid-impermeable wound dressing, to secure and control the delivery of FTY720- nanofiber scaffolds (FTY720-NF). We optimized release kinetics of the bilayer FTY720-NF to sustain drug release for up to 7d with safe, efficacious transdermal absorption and tissue biodistribution. Through comprehensive immunophenotyping, our results illustrate a pseudotime pro-regenerative state transition in recruited hybrid immune cells to the wound site. Additional histological assessments established a significant difference in full thickness ONF closure in mice on Day 7 following treatment with bilayer FTY720-NF, compared to controls. These findings demonstrate the utility of immunomodulatory strategies for oral wound healing, better positing the field to develop more efficacious treatment options for pediatric patients. One Sentence SummaryLocal delivery of bilayer FTY720-nanofiber scaffolds in an ONF mouse model promotes complete wound closure through modulation of pro-regenerative immune and stromal cells.

bioengineering↗

A yeast-based system to study SARS-CoV-2 Mpro structure and to identify nirmatrelvir resistant mutations

The SARS-CoV-2 main protease (Mpro) is a major therapeutic target. The Mpro inhibitor, nirmatrelvir, is the antiviral component of Paxlovid, an orally available treatment for COVID-19. As Mpro inhibitor use increases, drug resistant mutations will likely emerge. We have established a non-pathogenic system, in which yeast growth serves as a proxy for Mpro activity, enabling rapid identification of mutants with altered enzymatic activity and drug sensitivity. The E166 residue is known to be a potential hot spot for drug resistance and yeast assays showed that an E166R substitution conferred strong nirmatrelvir resistance while an E166N mutation compromised activity. On the other hand, N142A and P132H mutations caused little to no change in drug response and activity. Standard enzymatic assays confirmed the yeast results. In turn, we solved the structures of Mpro E166R, and Mpro E166N, providing insights into how arginine may drive drug resistance while asparagine leads to reduced activity. The work presented here will help characterize novel resistant variants of Mpro that may arise as Mpro antivirals become more widely used.

microbiology↗

SARS-CoV-2 surveillance in Norway rats (Rattus norvergicus) from Antwerp sewer system, Belgium

BackgroundSARS-CoV-2 human-to-animal transmission can lead to the establishment of novel reservoirs and the evolution of new variants with the potential to start new outbreaks in humans. AimWe tested Norway rats inhabiting the sewer system of Antwerp, Belgium, for the presence of SARS-CoV-2 following a local COVID-19 epidemic peak. In addition, we discuss the use and interpretation of SARS-CoV-2 serological tests on non-human samples. MethodsBetween November and December 2020, Norway rat oral swabs, feces and tissues from the sewer system of Antwerp were collected to be tested by RT-qPCR for the presence of SARS-CoV-2. Serum samples were screened for the presence of anti-SARS-CoV-2 IgG antibodies using a Luminex microsphere immunoassay (MIA). Samples considered positive were then checked for neutralizing antibodies using a conventional viral neutralization test (cVNT). ResultsThe serum of 35 rats was tested by MIA showing 3 potentially positive sera that were later shown to be negative by cVNT. All tissue samples of 39 rats analyzed tested negative for SARS-CoV-2 RNA. ConclusionThis is the first study that evaluates SARS-CoV-2 infection in urban rats. We can conclude that the sample of 39 rats had never been infected with SARS-CoV-2. We show that diagnostic serology tests can give misleading results when applied on non-human samples. SARS-CoV-2 monitoring activities should continue due to the emergence of new variants prone to infect Muridae rodents.

ecology↗