Spermatogonia Stem Cell Dynamics Following Hormonal Induction, Ischemic Disturbance \u3cem\u3eIn Vivo\u3c/em\u3e or Proliferation under \u3cem\u3eIn Vitro\u3c/em\u3e Culture in Pre- and Postpubertal Bulls

The overall aim of the studies described herein was to evaluate bovine spermatogonial cell dynamics under various conditions. Results from these experiments will provide the basis for potential production of offspring following spermatogonial stem cell transfer. Experiment 1 evaluated gonadotropin administration effects at initiation of inhibin passive immunization in Jersey bull calves on testicular morphology and development. Primary treatments consisted of control (KLH) or immunization (INH) plus a combination of saline, FSH, or GnRH. Administration of FSH at the time of initial immunization against inhibin significantly increased number of germ cells (92.2 ± 9 x 106 cells) compared to INH-Saline bulls (54.9 ± 10 x 106 cells) with INH-GnRH bulls being intermediate (64.5 ± 9 x 106 cells; P \u3c 0.05). These results suggested that gonadotropin administration at time of inhibin immunization increases number of germ cells in the testis. Experiment 2 evaluated transiently induced ischemia in testes of Jersey calves on morphology and development. Treatments consisted of control or banding for 2 h, 4 h, and 8 h periods. Transiently induced ischemia significantly decreased number of germ cells in 8 h (12.6 ± 5 x 106 cells) compared to 0 (38.1 ± 6 x 106 cells), 2 (31.9 ± 6 x 106 cells), and 4 h (33.4 ± 5 x 106 cells; P \u3c 0.05). These results suggested that transiently-induced ischemia significantly decreases number of germ, Sertoli and Leydig cells in the testis. Experiment 3 evaluated spermatogonial stem cells (SSC) proliferation, isolated from prepubertal and adult bulls, during short term in vitro culture. Spermatogonia were cultured in the presence or absence of a feeder monolayer (FL or NF), FBS type (FBS-S or FBS-SF), and media type (ELSC or RSC) treatment combinations. Viable type A spermatogonia survived under in vitro conditions and were able to proliferate and form different types of colonies. Furthermore, co-culture spermatogonial cells with a feeder monolayer plus FBS-S enhanced colony number (may be due to increasing cell viability). At 15 days of culture, colonies from both types of bulls were positive to AP. Therefore, these finding provide the basis for potential production of offspring through in vitro genetic manipulation such as intracytoplasmic sperm injection (ICSI), round spermatid injection (ROSI), or following SSC transfer

The rise and fall of the Phytophthora infestans lineage that triggered the Irish potato famine

Phytophthora infestans, the cause of potato late blight, is infamous for having triggered the Irish Great Famine in the 1840s. Until the late 1970s, P. infestans diversity outside of its Mexican center of origin was low, and one scenario held that a single strain, US-1, had dominated the global population for 150 years; this was later challenged based on DNA analysis of historical herbarium specimens. We have compared the genomes of 11 herbarium and 15 modern strains. We conclude that the nineteenth century epidemic was caused by a unique genotype, HERB-1, that persisted for over 50 years. HERB-1 is distinct from all examined modern strains, but it is a close relative of US-1, which replaced it outside of Mexico in the twentieth century. We propose that HERB-1 and US-1 emerged from a metapopulation that was established in the early 1800s outside of the species' center of diversity.Comment: To be published in eLIF

Prediction of parturition in Holstein dairy cattle using electronic data loggers

The objective of the present study was to assess the effect of parturition on behavioral activity [steps, standing time, lying time, lying bouts (LB), and duration of LB] 4 d before calving using electronic data loggers. Animals (n = 132) from 3 herds were housed in similar freestall barns using a prepartum pen 21 d before the expected calving date and were moved into a contiguous individual maternity pen for parturition. Electronic data loggers were placed on a hind leg of prepartum heifers (heifers, n = 33) and cows (cows, n = 99) at 7 ± 3 d before the expected calving date and removed at 14 ± 3 d in milk. Calving ease (scale 1–4), parity, calving date and time, and stillbirth (born dead or died within 24 h) were recorded. The number of steps (no./d), standing time (min/d), lying time (min/d), number of LB (no./d), and duration of LB (min/b) were recorded. Data were analyzed using MIXED procedures of SAS, adjusting for the herd effect. Only cows experiencing unassisted births (calving ease = 1) were included in the study. An activity index was developed to predict calving time. Heifers and cows with unassisted births had significantly higher number of steps and longer standing time, decreased lying time, and more LB of shorter duration 24 h before calving compared with d −4, −3, and −2. Additionally, the number of LB increased as both heifers and cows approached labor starting on d −2 and peaked at the day of calving. The time since the activity index increased over 50% to parturition did not differ between heifers and cows, and the activity index revealed the shift in activity on average 6 h 14 min (range from 2 h to 14 h 15 min) before calf birth. This study provided evidence that heifers and cows approaching parturition showed a similar, but distinct, behavioral pattern that can be observed on average 6 h before calf birth. The potential benefits of electronic data loggers as predictors of parturition along with proactive management practices should improve the overall survival and welfare of both the dam and calf

Mitochondrial genomes of giant deers suggest their late survival in Central Europe

The giant deer Megaloceros giganteus is among the most fascinating Late Pleistocene Eurasian megafauna that became extinct at the end of the last ice age. Important questions persist regarding its phylogenetic relationship to contemporary taxa and the reasons for its extinction. We analyzed two large ancient cervid bone fragments recovered from cave sites in the Swabian Jura (Baden-Württemberg, Germany) dated to 12,000 years ago. Using hybridization capture in combination with next generation sequencing, we were able to reconstruct nearly complete mitochondrial genomes from both specimens. Both mtDNAs cluster phylogenetically with fallow deer and show high similarity to previously studied partial Megaloceros giganteus DNA from Kamyshlov in western Siberia and Killavullen in Ireland. The unexpected presence of Megaloceros giganteus in Southern Germany after the Ice Age suggests a later survival in Central Europe than previously proposed. The complete mtDNAs provide strong phylogenetic support for a Dama-Megaloceros clade. Furthermore, isotope analyses support an increasing competition between giant deer, red deer, and reindeer after the Last Glacial Maximum, which might have contributed to the extinction of Megaloceros in Central Europe

Effect of milk cessation method at dry-off on behavioral activity of dairy cows

Drying cows off at the end of lactation is a routine management practice in dairy operations. Most dairies in the United States and many other countries dry cows off abruptly (e.g., stop milking cows on a set day), which has been shown to affect cow comfort. Gradually reducing milk production is another approach to dry cows off, routinely used in some countries and herds. The objective of the study was to evaluate the effects of abrupt and gradual milk cessation and milk yield at the time on cow activity after dry-off. Daily lying time, number of lying bouts per day, average lying bout length, and steps taken per day by abruptly and gradually dried-off cows were monitored by data loggers for 2 wk before and after the final milking at the end of lactation. Gradual cows were milked once daily for the last week of lactation, and abrupt cows were milked as usual (3 x /d) until the end of lactation. Gradual cessation of milking significantly reduced milk yield by the day of dry-off. After dry-off, gradual cows tended to have longer lying bouts than abrupt cows, but no other differences in cow activity between the 2 treatments were observed. Regardless of the dry-off method, the average length of a lying bout decreased by 4 min and total daily lying time decreased by 19 min after dry-off for each 5-kg increase in milk yield before dry-off. Lying behavior of primiparous cows was more affected by the level of milk yield at dry-off than that of older cows. A reduction in lying times with increasing milk yield may indicate discomfort due to the accumulating milk in the udder. Using a method that lowers milk production before dry-off and managing primiparous and multiparous cows separately around dry-off are beneficial for cow comfort after dry-off.Peer reviewe

On Roth’s “human fossil” from Baradero, Buenos Aires Province, Argentina: morphological and genetic analysis

The “human fossil” from Baradero, Buenos Aires Province, Argentina, is a collection of skeleton parts first recovered by the paleontologist Santiago Roth and further studied by the anthropologist Rudolf Martin. By the end of the nineteenth century and beginning of the twentieth century it was considered one of the oldest human skeletons from South America's southern cone. Here, we present the results of an interdisciplinary approach to study and contextualize the ancient individual remains. We discuss the context of the finding by first compiling the available evidence associated with the historical information and any previous scientific publications on this individual. Then, we conducted an osteobiographical assessment, by which we evaluated the sex, age, and overall preservation of the skeleton based on morphological features. To obtain a 3D virtual reconstruction of the skull, we performed high resolution CT-scans on selected skull fragments and the mandible. This was followed by the extraction of bone tissue and tooth samples for radiocarbon and genetic analyses, which brought only limited results due to poor preservation and possible contamination. We estimate that the individual from Baradero is a middle-aged adult male. We conclude that the revision of foundational collections with current methodological tools brings new insights and clarifies long held assumptions on the significance of samples that were recovered when archaeology was not yet professionalized

Comparison of target enrichment strategies for ancient pathogen DNA

In ancient DNA research, the degraded nature of the samples generally results in poor yields of highly fragmented DNA; targeted DNA enrichment is thus required to maximize research outcomes. The three commonly used methods ? array-based hybridization capture and in-solution capture using either RNA or DNA baits ? have different characteristics that may influence the capture efficiency, specificity and reproducibility. Here we compare their performance in enriching pathogen DNA of Mycobacterium leprae and Treponema pallidum from 11 ancient and 19 modern samples. We find that in-solution approaches are the most effective method in ancient and modern samples of both pathogens and that RNA baits usually perform better than DNA baits