Endothelial cells and angiogenesis in the horse in health and disease—A review

The cardiovascular system is the first functional organ in the embryo, and its blood vessels form a widespread conductive network within the organism. Blood vessels develop de novo, by the differentiation of endothelial progenitor cells (vasculogenesis) or by angiogenesis, which is the formation of new blood vessels from existing ones. This review presents an overview of the current knowledge on physiological and pathological angiogenesis in the horse including studies on equine endothelial cells. Principal study fields in equine angiogenesis research were identified: equine endothelial progenitor cells; equine endothelial cells and angiogenesis (heterogeneity, markers and assessment); endothelial regulatory molecules in equine angiogenesis; angiogenesis research in equine reproduction (ovary, uterus, placenta and conceptus, testis); angiogenesis research in pathological conditions (tumours, ocular pathologies, equine wound healing, musculoskeletal system and laminitis). The review also includes a table that summarizes in vitro studies on equine endothelial cells, either describing the isolation procedure or using previously isolated endothelial cells. A particular challenge of the review was that results published are fragmentary and sometimes even contradictory, raising more questions than they answer. In conclusion, angiogenesis is a major factor in several diseases frequently occurring in horses, but relatively few studies focus on angiogenesis in the horse. The challenge for the future is therefore to continue exploring new therapeutic angiogenesis strategies for horses to fill in the missing pieces of the puzzle.     

Climatic response and impacts of drought on oaks at urban and forest sites

This study focuses on the climate and growth response of the sessile oak (Quercus petraea (Matt.) Liebl.) and the northern red oak (Quercus rubra L.) using dendrochronological methods. Tree-ring series of street trees in the city of Dresden, Germany and in a nature reserve close to the urban area were analysed, and the climate and growth response and moving correlation functions (CF) were computed. Moreover, the impact of 13 years of drought was examined by superposed epoch analysis (SEA). Our results show that differences emerge from peculiarities of the different site conditions, indicating that city oaks contain a higher level of noise in their ring width data due to human activities that degrade the strength of growth-climate associations. Importantly, climatic conditions during the previous summer and autumn and during the current spring season display significant correlations with annual growth. The stability of the climate–growth relationship was tested via moving correlation functions. A strong increase in the correlation with the temperature and precipitation in April was found for the trees of northern red oak in forests. Drought years induced significant reductions in radial growth for the northern red oak only. Nevertheless, the long-term impact of drought years must be considered as marginal because of the fast recovery of the radial growth after one to two years. In the future, the growth of the northern red oak may be restricted by an increased frequency of droughts and warmer and drier conditions in April.     

Presence and genetic variability of Piscine orthoreovirus genotype 1 (PRV‐1) in wild salmonids in Northern Europe and North Atlantic Ocean

Piscine orthoreovirus genotype 1 (PRV‐1) is widespread in farmed Atlantic salmon (Salmo salar L.) populations in northern Europe, Canada and Chile. PRV‐1 occurs in wild fish in Norway and Canada; however, little information of its geographical distribution in wild populations is currently available, and the effect of PRV‐1 infection in wild populations is currently unknown. In this study, we present the findings of a survey conducted on 1,130 wild salmonids sampled in Denmark, Sweden, Ireland, Faroe Islands, France, Belgium and Greenland between 2008 and 2017. PRV‐1 is reported for the first time in wild salmonids in Denmark, Sweden, Faroe Island and Ireland. The annual PRV‐1 prevalence ranged from 0% in France, Belgium and Greenland to 43% in Faroe Islands. In total, 66 samples tested positive for PRV‐1, including Atlantic salmon broodfish returning to spawn and Atlantic salmon collected at the feeding ground north of Faroe Islands. The phylogenetic analysis of S1 sequences of the PRV‐1 isolates obtained in this survey did not show systematic geographical distribution. This study sheds light on the spread and genetic diversity of the virus identified in populations of free‐living fish and provides rationale for screening wild broodfish used in restocking programmes.     

Dung application increases CH<Subscript>4</Subscript> production potential and alters the composition and abundance of methanogen community in restored peatland soils from Europe

Peatland restoration via rewetting aims to recover biological communities and biogeochemical processes typical to pristine peatlands. While rewetting promotes recovery of C accumulation favorable for climate mitigation, it also promotes methane (CH₄) emissions. The potential for exceptionally high emissions after rewetting has been measured for Central European peatland sites previously grazed by cattle. We addressed the hypothesis that these exceptionally high CH₄ emissions result from the previous land use. We analyzed the effects of cattle dung application to peat soils in a short- (2 weeks), a medium- (1 year) and a long-term (grazing) approach. We measured the CH₄ production potentials, determined the numbers of methanogens by mcrA qPCR, and analyzed the methanogen community by mcrA T-RFLP-cloning-sequencing. Dung application significantly increased the CH₄ production potential in the short- and the medium-term approach and non-significantly at the cattle-grazed site. The number of methanogens correlated with the CH₄ production in the short- and the long-term approach. At all three time horizons, we found a shift in methanogen community due to dung application and a transfer of rumen methanogen sequences (Methanobrevibacter spp.) to the peatland soil that seemed related to increased CH₄ production potential. Our findings indicate that cattle grazing of drained peatlands changes their methanogenic microbial community, may introduce rumen-associated methanogens and leads to increased CH₄ production. Consequently, rewetting of previously cattle-grazed peatlands has the potential to lead to increased CH₄ emissions. Careful consideration of land use history is crucial for successful climate mitigation with peatland rewetting.     

Bottom-up down from the top: Honeydew as a carbon source for soil organisms

Honeydew produced by aphids is a well-studied food source for mutualistic ants. Although considerable amounts drop onto the soil surface there are hardly any studies dealing with the potential effects of this additional C source for soil organisms, particularly those living at the soil surface. We studied this question by simulating honeydew and investigating plots under Populus canescens formerly infested with aphids on two ruderal sites differing in soil organic matter content and vegetation cover. The simulated honeydew input increased microbial biomass with some delay in week 10. Both natural and simulated honeydew raised the activity densities of an epigeic Collembola taxon, the Bourletiellidae, but not of the dominant Hemisotoma thermophila. The honeydew effect varied over time and with the site, and was more pronounced at the nutrient-poor site for Collembola, but not for microbial biomass. Ant consumption reduced the amount of honeydew reaching the soil surface by 50%. The activity density of H. thermophila was negatively related to ants and spiders, hinting at a top-down control. Honeydew clearly acts as a bottom-up force for soil organisms, which is however only part of the complex network connecting the food webs of primary producers and decomposers.     

Simple and Rapid Quality Control of Sulfated Glycans by a Fluorescence Sensor Assay—Exemplarily Developed for the Sulfated Polysaccharides from Red Algae Delesseria sanguinea

Sulfated polysaccharides (SP) from algae are of great interest due to their manifold biological activities. Obstacles to commercial (especially medical) application include considerable variability and complex chemical composition making the analysis and the quality control challenging. The aim of this study was to evaluate a simple microplate assay for screening the quality of SP. It is based on the fluorescence intensity (FI) increase of the sensor molecule Polymer-H by SP and was originally developed for direct quantification of SP. Exemplarily, 65 SP batches isolated from the red alga Delesseria sanguinea (D.s.-SP) and several other algae polysaccharides were investigated. Their FI increase in the Polymer-H assay was compared with other analytical parameters. By testing just one concentration of a D.s.-SP sample, quality deviations from the reference D.s.-SP and thus both batch-to-batch variability and stability can be detected. Further, structurally distinct SP showed to differ in their concentration-dependent FI profiles. By using corresponding reference compounds, the Polymer-H assay is therefore applicable as identification assay with high negative predictability. In conclusion, the Polymer-H assay showed to represent not only a simple method for quantification, but also for characterization identification and differentiation of SP of marine origin.     

Dairy calf rearing unit and infectious diseases: diarrhea outbreak by bovine coronavirus as a model for the dispersion of pathogenic microorganisms

Dairy calf rearing unit is a management system that is only recently being implemented by some milk producer’s cooperatives in southern Brazil. However, aspects related to the health profile of the heifer calves that arrive in the rearing unit as well as about biosecurity practices and microbiological challenges have not yet been evaluated in this rearing system in a tropical country. Diarrhea is the main and most frequent consequence of enteric infections in newborn calves. This study, through some etiological and epidemiological characteristics of an outbreak of neonatal diarrhea, has the aim to alert to the possibility of pathogenic microorganism spread in a dairy heifer calf rearing unit. The diarrhea outbreak presented some non-regular characteristics observed in bovine coronavirus (BCoV) enteric infections in dairy calves. The spread of infection was extremely rapid (1 week); the attack rate (>?50%) was much higher than that observed in calves subjected to conventional rearing; and the age range (5 to 90 days) of the affected heifer calves was much broader than that often observed in the BCoV diarrhea worldwide. These unusual epidemiological characteristics observed in this BCoV diarrhea outbreak raise awareness of the health threat present in calf rearing units as well as of the easy and rapid viral spread in a population of young animals from different dairy herds and, therefore, with very distinct immunological status.