Biology subjects

Acacio, M.

Publications and source records attributed to Acacio, M..

4 recordsLinked to original sources

bioRxiv2024

Factors affecting the individual probability of infection with a prevalent pathogen (Mycoplasma) and the effect on Griffon vultures' movement behavior

Mycoplasmas are known as commensals and pathogenic bacteria of various raptor species causing clinical or subclinical infections. However, little is known about the prevalence of mycoplasma in captive and wild raptors and its significance to their health. In Israel, the Griffon vulture (Gyps fulvus; hereafter Griffons) is considered critically endangered, and its intensive management program includes population monitoring and restocking (captive-born or imported rehabilitated wild Spanish Griffons). Here we survey the prevalence of Mycoplasma species in both the wild and captive populations. During 2019-2020, we collected 244 tracheal swab samples from 167 unique individuals. We used PCR analysis to identify Mycoplasma species. First, we identified nine spp., including species not yet described in Israel or for Griffon vultures. Second, imported Griffons showed a higher prevalence and a different diversity of species in comparison to the local ones, suggesting that at least one Mycoplasma species (Sp 18b) was introduced into the native population. Third, juvenile Griffons had a higher prevalence, different species composition, and stronger reduction in movement compared to adults, confirming the susceptibility of this group to mycoplasma infections. GPS-tracking of 60 free-ranging individuals showed that even in the absence of apparent clinical signs, Griffons infected with mycoplasma, and especially sub-adults flew less (shorter distances and periods). These findings underscore the importance of considering potential pathogen introductions in population reinforcement and reintroduction initiatives, providing valuable insights for similar conservation programs globally. Further, they demonstrate the potential of long-term tracking for detecting subclinical effects that are unnoticeable in clinical examination.

ecology↗

bioRxiv2024

Ovarian support cell in vitro maturation (OSC-IVM) results in healthy murine live births with no evidence of reprotoxicology in a multigenerational study

Study questionDoes application of human stem cell-derived ovarian support cells (OSCs) for in vitro maturation (IVM) have a safe reproductive toxicity profile? Summary answerThe use of OSC-IVM co-culture improves blastocyst formation in a mouse model and results in healthy live births with no evidence of reprotoxicity. What is known alreadyAbbreviated stimulation to obtain immature oocytes combined with a successful IVM offers a promising alternative to traditional in vitro fertilization, reducing hormonal doses and making IVF shorter and safer. Recently, we developed an OSC platform derived from human induced pluripotent stem cells (hiPSCs) that replicate dynamic ovarian function in vitro, enhancing human oocyte maturation and yielding an improved blastocyst formation rate compared to commercial IVM options. However, the reproductive toxicity profile, commonly assessed via murine multigenerational models, for OSC-IVM remains unknown. Study design, size, durationA total of 70 B6/CBA 6-8-week-old stimulated female mice were used in this study to collect immature mouse oocytes (n=2,025) at the germinal vesicle (GV) stage. Half of these oocytes were retrieved denuded (denuded oocytes condition, n= 930), while the remaining oocytes were kept with the cumulus cells (COCs condition, n= 1,095) to simulate the two possible dispositions of oocytes during clinical practice. Oocytes from each condition, denuded oocytes and COCs, were randomly assigned to either commercially available traditional IVM media (MediCult-IVMTM, Origio) group (control group) or the same traditional IVM media supplemented with human OSCs (FertiloTM, Gameto Inc.) to form the OSC-IVM group (test group). Participants/materials, setting, methodsOocytes from each condition, denuded oocytes and COCs, were subjected to in vitro culture for 18-20 hours. After IVM, metaphase II (M2) oocytes were inseminated by intracytoplasmic sperm injection (ICSI) and cultured to assess blastocyst formation in vitro. Embryos that reached the blastocyst stage on day five were vitrified using Kitazatos protocol in preparation for embryo transfers. A group of M2 oocytes and blastocyst embryos were employed for quality analyses by immunofluorescence. Vitrified blastocysts were warmed and transferred to pseudopregnant females (4-5 embryos per uterine horn), evaluating the F1 offspring. Pup characteristics were tracked, including weight, length, sex ratio, and physiology. Weekly monitoring assessed mouse behavior and development. At reproductive age, select F1 mice were outbred to wildtype mice to produce the F2 generation, analyzing live births, sex ratio, morphology, and behavior across groups. Moreover, hormonal and organ histological analyses were performed in F1 mice to further explore the overall health of the progeny. Main results and the role of chanceIn contrast to findings in humans, in mice OSC-IVM generally led to a decreased maturation rate compared to Traditional-IVM (68.6% {+/-} 14.1% versus 80.9% {+/-} 5.9%, p=0.0101). Subsequent embryo culture yielded significantly different fertilization rates between the four groups (p=0.0055). Specifically, OSC-IVM with COCs significantly differed from Traditional-IVM with denuded oocytes (89.5 {+/-} 10.5 versus 96.5 {+/-} 4.8, p=0.0098). There were no differences in the cleavage rates (p=0.7547). However, there was a significant distinction in the blastocyst formation (p=0.0068), wherein OSC-IVM with COCs showed a greater formation rate compared to Traditional-IVM for both denuded oocytes and COCs (56.1% {+/-} 19.2% versus 41.5% {+/-} 15.9% and 38.0% {+/-} 16.2%; p=0.0408, and p=0.0063). Spindle morphology analysis demonstrated normal spindle morphology in denuded oocytes and COCs under both Traditional-IVM and OSC-IVM. Moreover, embryo analysis showed no significant difference in inner cell mass count (p=0.1550). Following embryo transfers, analysis of live births showed no significant distinctions between groups regarding delivery, sex ratio, pup length, developmental and behavioral abnormalities, hormonal values or histopathological anomalies in the F1 generation. Evaluation of the F2 generation also showed no significant differences in live births, sex ratio, or developmental/behavioral abnormalities between groups, further validating the absence of long-term implications and transgenerational effects derived from OSC-IVM culture. Limitations, reasons for cautionAlthough this study was conducted in compliance with European Medicines Agency (EMA) ICH E6 (R2) Good clinical practice scientific guidelines to demonstrate the OSC safety, human clinical studies evaluating in vivo and live birth outcomes are necessary to corroborate the findings of this study. Wider implications of the findingsThis study provides evidence of the safety of using the OSC-IVM system, as evidenced by the lack of adverse effects on in vitro embryo development post OSC-IVM and on the health and fertility of offspring across successive generations in vivo. Trial registration numberN/A

pharmacology and toxicology↗

bioRxiv2024

Extreme temperatures impede the release success of captive-bred avian scavengers

Conservation translocations (reinforcements and reintroductions) are central for managing various endangered species, yet, their implementation is logistically and financially challenging. Because many translocations fail due to the mortality of released individuals, identifying and preventing these factors is crucial. Here we examine risk factors affecting the post-release survival of the Griffon vulture (Gyps fulvus). The Israeli population is facing extinction, and the recovery efforts by the local Nature and Parks Authority include supplemental releases of individuals from captive-breeding or rehabilitated birds (mostly imported from Spain). We use GPS tracking and thermometers to compare movement, behavior, and weather conditions experienced by released and wild-born individuals active in the same area and time. Our results show that the Judean Desert release site had a significantly lower survival rate than other release sites included in the program. After excluding several possible factors (e.g. known pathogens) with pathological examinations, we found that released individuals at this area were exposed to higher temperatures preceding their death (compared to wild-born griffons nearby), suggesting heat stress as the cause of death. Arguably, they failed to avoid the harsh environmental conditions, resulting in overheating due to their inexperience and undeveloped flight ability, as reflected by their lower probabilities of flying and shorter travel distances per day compared to wild-born vultures. These findings have led to adjustments of the local release protocol, (namely winter releases) resulting in a significant improvement in the early survival of translocated Griffons in the Judean Desert. Accounting for the harmful effects of extreme weather conditions is particularly important in a world facing climate change. More broadly, this sequence of scientific investigation with data integration from ecological, clinical, and biotelemetry sources, leading to improvement in translocation success demonstrates how conservation practices can be optimized by supporting studies to ensure the survival of endangered species in the wild.

ecology↗

bioRxiv2024

Mechanisms underlying the loss of migratory behaviour in a long-lived bird

Human-induced environmental changes are shifting the migration patterns of birds worldwide. Species are adjusting migration timings, shortening and diversifying migratory routes, or even completely disrupting migration and transitioning towards residency. Whilst the ultimate causes driving changes in migratory patterns are well established, the underlying mechanisms by which migratory species adapt to environmental change remain unclear. Here, we studied the mechanisms driving the recent and rapid loss of migratory behaviour in Iberian white storks Ciconia ciconia, a long-lived and previously fully migratory species through the African-Eurasian flyway. We combined 25 years of census data, GPS-tracking data from 213 individuals (80 adults and 133 first-year juveniles) followed for multiple years, and whole-genome sequencing, to disentangle whether within- (phenotypic flexibility) or between- (developmental plasticity or microevolution, through selection) individual shifts in migratory behaviour over time can explain the observed population-level changes towards residency. Between 1995 and 2020, the proportion of individuals no longer migrating and remaining in Southern Europe year-round increased dramatically, from 18% to 68-83%. We demonstrate that this behavioural shift is likely explained by developmental plasticity. Within first-year birds, 98% crossed the Strait of Gibraltar towards their African wintering grounds, in Morocco or Sub-Saharan Africa. However, the majority shifted towards a non-migratory strategy as they aged - the proportion of migrants decreased to 67% and 33%, on their second and third year of life, respectively - suggesting that migratory behaviour is determined during ontogeny. Supporting these findings, only 19% of GPS-tracked adults migrated. Moreover, we did not find evidence of phenotypic flexibility, as adults were highly consistent in migratory behaviour over multiple years (only 3 individuals changed strategy between years, out of 113 yearly transitions), nor of selection acting on genetic variation, since genomes of migrants and residents are essentially undifferentiated. Our results suggest that through developmental plasticity, traits that are plastic during specific windows of development, become fixed during adulthood. Thus, inter-generational shifts in the frequency of migratory and non-migratory young individuals could drive population changes in migratory behaviour. This can provide a fast mechanism for long-lived migratory birds to respond to rapid human-driven environmental changes.

evolutionary biology↗