The hidden microbial ecosystem in the perennial ice from a Pyrenean ice cave

Over the last years, perennial ice deposits located within caves have awakened interest as places to study microbial communities since they represent unique cryospheric archives of climate change. Since the beginning of the twentieth century, the temperature has gradually increased, and it is estimated that by the end of this century the increase in average temperature could be around 4.0°C. In this context of global warming the ice deposits of the Pyrenean caves are undergoing a significant regression. Among this type of caves, that on the Cotiella Massif in the Southern Pyrenees is one of the southernmost studied in Europe. These types of caves house microbial communities which have so far been barely explored, and therefore their study is necessary. In this work, the microbial communities of the Pyrenean ice cave A294 were identified using metabarcoding techniques. In addition, research work was carried out to analyze how the age and composition of the ice affect the composition of the bacterial and microeukaryotic populations. Finally, the in vivo effect of climate change on the cellular machinery that allow microorganisms to live with increasing temperatures has been studied using proteomic techniques.

The untapped potential of macrofossils in ancient plant DNA research

The rapid development of ancient DNA analysis in the last decades has induced a paradigm shift in ecology and evolution. Driven by a combination of breakthroughs in DNA isolation techniques, high-throughput sequencing, and bioinformatics, ancient genome-scale data for a rapidly growing variety of taxa are now available, allowing researchers to directly observe demographic and evolutionary processes over time. However, the vast majority of paleogenomic studies still focus on human or animal remains. In this article, we make the case for a vast untapped resource of ancient plant material that is ideally suited for paleogenomic analyses: plant remains, such as needles, leaves, wood, seeds, or fruits, that are deposited in natural archives, such as lake sediments, permafrost, or even ice caves. Such plant remains are commonly found in large numbers and in stratigraphic sequence through time and have so far been used primarily to reconstruct past local species presences and abundances. However, they are also unique repositories of genetic information with the potential to revolutionize the fields of ecology and evolution by directly studying microevolutionary processes over time. Here, we give an overview of the current state-of-the-art, address important challenges, and highlight new research avenues to inspire future research.

Glacial Ice Age Shapes Microbiome Composition in a Receding Southern European Glacier

Glaciers and their microbiomes are exceptional witnesses of the environmental conditions from remote times. Climate change is threatening mountain glaciers, and especially those found in southern Europe, such as the Monte Perdido Glacier (northern Spain, Central Pyrenees). This study focuses on the reconstruction of the history of microbial communities over time. The microorganisms that inhabit the Monte Perdido Glacier were identified using high-throughput sequencing, and the microbial communities were compared along an altitudinal transect covering most of the preserved ice sequence in the glacier. The results showed that the glacial ice age gradient did shape the diversity of microbial populations, which presented large differences throughout the last 2000 years. Variations in microbial community diversity were influenced by glacial conditions over time (nutrient concentration, chemical composition, and ice age). Some groups were exclusively identified in the oldest samples as the bacterial phyla Fusobacteria and Calditrichaeota, or the eukaryotic class Rhodophyceae. Among groups only found in modern samples, the green sulfur bacteria (phylum Chlorobi) stood out, as well as the bacterial phylum Gemmatimonadetes and the eukaryotic class Tubulinea. A patent impact of human contamination was also observed on the glacier microbiome. The oldest samples, corresponding to the Roman Empire times, were influenced by the beginning of mining exploitation in the Pyrenean area, with the presence of metal-tolerant microorganisms. The most recent samples comprise 600-year-old ancient ice in which current communities are living.

Escenarios, tempo e indicadores paleoambientales para la identificación del Antropoceno en el paisaje vegetal del Pirineo Central (NE Iberia)

The Anthropocene is related to the origin of current landscape configuration, and in terms of vegetation, with the consideration of human action as main forcing of clear, intense and permanent changes through time. In this paper we compile and compare data from palynological sequences, microcharcoal records, archaeological sites and radiocarbon dates from palaeofires located in the Central Pyrenees besides historical documents, and we argue that some evidences related to early deforestation processes and use of human fire are not so clear than some authors point. Conversely, indicators of unequivocal human use and the origin of cultural landscapes are located only a few centuries and not a few millennia ago. In fact, high temporal and spatial variability is recorded until the Middle Ages (last 700 years, 1300 AD), when a series of consistent and permanent changes suggest the onset of the Anthropocene.

Evaluation of experimental vaccines for bovine viral diarrhea in bovines, ovines and guinea pigs

The bovine viral diarrhea virus (BVDV) infection control should be based on elimination of persistently infected animals and on immunization through vaccination, to prevent fetal infection. However, the efficacy of inactivated BVDV vaccines is variable due to its low immunogenicity. This study evaluated the humoral immune response against homologous and heterologous strains of 7 inactivated BVDV vaccines, in bovines and two experimental models (ovine and guinea pig) which might be used to test candidate vaccines. Vaccines formulated with BVDV Singer, Oregon, NADL, and multivalent, induced seroconversion in the three animal models studied, reaching antibody titres higher than 2. Vaccine containing 125C -genotype 2- only induced a low antibody response in ovine, while VS-115 NCP vaccine was not immunogenic. Furthermore, bovine sera at 60 dpv presented homologous as well as heterologous antibody response, indicating a high degree of cross-reactivity among the strains studied. However, when bovine sera were tested against the Argentine field strain 00-693, they showed the lowest levels of cross-reactivity, suggesting the need of continued surveillance to identify and characterize emerging field BVDV strains. Finally, optimal correlations between bovine-ovine and bovine-guinea pig models were observed, indicating that two alternative species could replace bovines when testing the immunogenicity of BVDV candidate vaccines.

[Group A bovine rotavirus: diagnosis and antigenic characterization of strains circulating in the Argentine Republic, 1994-1999]

Group A Bovine Rotavirus (BRV) has been identified as a major cause of neonatal diarrhea in cattle. The study was aimed to determine the prevalence of BRV and to antigenically characterize the G-types of circulating strains in dairy and beef herds in Argentina. A total of 1129 stool samples from diarrheic calves was analyzed from 1994 to 1999. The samples were initially screened for RV by ELISA and PAGE, and then G-typed using monoclonal antibodies (Mab) directed against G1, G2, G3, G6 and G10-specific epitopes. Forty percent (452/1129) of the samples were positive for RV by ELISA, while 24.7% (279/1129) were also positive for PAGE. VP7 was detected in the 70.5% (319/452) of the positive samples using a broadly reactive Mab (C60); 32.6% (104/319) were G6, 15.4% (49/319) were G10, and 6% (19/319) were G1. However, 46.1% (147/319) of the samples remained untypable. Rotavirus diarrhea prevalences were comparable in beef and dairy herds (87.3% and a 74.4%, respectively). Finally, G6 was the most prevalent G-type circulating in beef herds while G10 prevailed in dairy herds. A better understanding of RV epidemiology will contribute to the optimization of current vaccines and prevention programs of RV diarrhea in calves.