During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO
2
) ...exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO
2
seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO
2
gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO
2
cycles from 48 European stations were available for 2017 and 2018. Earlier data were retrieved for comparison from international databases or national networks. Here, we show that the usual summer minimum in CO
2
due to the surface carbon uptake was reduced by 1.4 ppm in 2018 for the 10 stations located in the area most affected by the temperature anomaly, mostly in Northern Europe. Notwithstanding, the CO
2
transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO
2
uptake by photosynthesis and/or a reduction in respiration driven by the depletion of substrate for respiration inherited from the previous months due to the drought. For stations with sufficiently long time series, the CO
2
anomaly observed in 2018 was compared to previous European droughts in 2003 and 2015. Considering the areas most affected by the temperature anomalies, we found a higher CO
2
anomaly in 2003 (+3 ppm averaged over 4 sites), and a smaller anomaly in 2015 (+1 ppm averaged over 11 sites) compared to 2018.
This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
1 Institut für Mikrobiologie und Tierseuchen, Freie Universität Berlin, Philippstr. 13, 10115 Berlin, Germany
2 Institut für Veterinär-Anatomie, Freie Universität Berlin, Koserstr. 20, 14195 Berlin, ...Germany
Correspondence Peter Schierack schierack.peter{at}vetmed.fu-berlin.de
In this study, the Enterobacteriaceae microbiota, including their diversity as well as the distribution of haemolytic and virulence gene-harbouring Escherichia coli of 56-day-old healthy piglets, was characterized. Both the composition and the diversity of Enterobacteriaceae populations varied considerably between individual pigs and intestinal sections. E. coli , Enterobacter cloacae , Citrobacter freundii and Klebsiella pneumoniae dominated the Enterobacteriaceae microbiota. However, mucosa-associated Enterobacteriaceae were scarce or in some cases undetectable. The majority of E. coli clones from the jejunum were also found in the colon, with up to 10 different E. coli clones in one intestinal section. Other Enterobacteriaceae species were represented by only one clone localized to one intestinal section. While several piglets did not harbour virulence gene-positive or haemolytic E. coli , such strains dominated intestinal sections of other animals. This study reveals that the diversity of intestinal Enterobacteriaceae is clearly individual. In general, Enterobacteriaceae do not appear to be a consistent fraction of the microbiota of the jejunum. High numbers of adherent bacteria do not appear to be essential for successful intestinal colonization, and E. coli clones do not necessarily colonize distinct intestinal sections based on the particular phylogenetic affiliation. Furthermore, dominance of haemolytic or virulence gene-positive E. coli does not correlate with disease. Finally, probiotic Enterococcus faecium feed supplementation does not affect the Enterobacteriaceae microbiota.
Figures showing electron micrographs of mucosa-attached bacteria, the incidence of haemolysis among E. coli colonies, and the ECOR grouping of E. coli from pigs, are available as supplementary data with the online version of this paper.
The influence of the probiotic bacterium
Enterococcus faecium SF68 on the immune system and the intestinal colonization of pigs were determined in a feeding experiment with sows and piglets. Mucosal ...immunity of the developing piglets was monitored by isolation and detection of intestinal lymphocyte cell populations from the proximal jejunal epithelium and the continuous Peyers patches by the use of flow cytometry. The levels of intestinal IgA in both groups of piglets were compared, as well as total IgG in the serum of sows and piglets. Feces of the sows and intestinal contents of the piglets were taken for determination of total anaerobe and coliform bacterial counts in both probiotic and control groups. Villus length and depth of the crypts were measured in the jejunum of sacrificed piglets to monitor the development of the intestinal mucosal surface amplification.
Total serum IgG of the sows appeared to be unaffected. Piglets of both groups showed similar IgG levels up to 5 weeks after birth with a slight tendency toward lower values in the probiotic group. At an age of 8 weeks the total IgG levels of the probiotic animals were significantly lower (
p
<
0.01). No differences were observed in the populations of CD4
+ and CD8
+ T cells in the Peyers patches. However, the levels of cytotoxic T cells (CD8
+) in the jejunal epithelium of piglets of the probiotic group were significantly reduced. The depth of the jejunal crypts and length of the villi were similar in both groups, suggesting the relative T-cell population differences were not due to alterations in the epithelial cell numbers. The total anaerobe and coliform bacterial populations were not significantly affected by the probiotic treatment, either in sows or in the piglets. However, a remarkable decline in the frequency of β-haemolytic and O141 serovars of
Escherichia coli was observed in the intestinal contents of probiotic piglets, suggesting an explanation for the reduction in cytotoxic T-cell populations.
During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO 2) ...exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO 2 seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO 2 gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO 2 cycles from 48 European stations were available for 2017 and 2018. Earlier data were retrieved for comparison from international databases or national networks. Here, we show that the usual summer minimum in CO 2 due to the surface carbon uptake was reduced by 1.4 ppm in 2018 for the 10 stations located in the area most affected by the temperature anomaly, mostly in Northern Europe. Notwithstanding, the CO 2 transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO 2 uptake by photosynthesis and/or a reduction in respiration driven by the depletion of substrate for respiration inherited from the previous months due to the drought. For stations with sufficiently long time series, the CO 2 anomaly observed in 2018 was compared to previous European droughts in 2003 and 2015. Considering the areas most affected by the temperature anomalies, we found a higher CO 2 anomaly in 2003 (+3 ppm averaged over 4 sites), and a smaller anomaly in 2015 (+1 ppm averaged over 11 sites) compared to 2018. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
The pecten oculi is a highly vascularized and pigmented organ that overlies the optic disc and projects into the vitreous body in the avian eye. First reported over 300 years ago, its function(s) ...remains a puzzle to ornithologists, ophthalmologists and anatomists. Morphometric study of this unique organ was undertaken in birds exhibiting apparently different visual acuities, namely two species of diurnal birds (the ground-dwelling domestic fowl Gallus gallus var. domesticus and a highly active predator bird, the black kite (Milvus migrans) and a nocturnal bird (the spotted-eagle owl Bubo bubo africanus). The volume of the owl's eye was 4.8 and 2.2 times larger than that of the fowl and the kite, respectively. However, the pecten of the fowl consisted of more pleats (16–18) compared to the kite (12–13) and the owl (5–6). The volume of the pecten of the kite was 1.4 and 2.7 times larger than that of the fowl and the owl, respectively (P < 0.05). Similarly, the surface area of the pecten of the kite was 2.6 and 4 times larger than that of the fowl and owl, respectively (P < 0.05). The volume density of blood vessels (lumen and wall) in the pecten of the kite, fowl and owl comprised 67.7%, 66.9% and 62.6%, respectively, the pigmented tissue constituting the rest. Both the volume density and the volume of the blood in the pecten were higher in the diurnal birds (kite, fowl) than the owl (P < 0.05). The surface area of the capillary luminal surface was 1.7 and 5.3 times higher in the kite than in the fowl and the owl, respectively (P < 0.05). These results suggest that the functional morphology of the pecten correlates with the life-style of the bird and with functional need, and lends further support to the nutritive role of the pecten.
Summary
The intestinal morphology of 7‐week‐old pigs was investigated by light (LM) and scanning electron microscopy (SEM). The piglets were fed either a semisynthetic or a cereal‐based diet. The ...shapes of the intestinal villi and crypts of the duodenum, jejunum and ileum were examined. The villi were predominantly tongue‐shaped. In the duodenum they were also ridged, branched and folded, and in the jejunum they were also leaf‐like and ridged. At places with lymph follicles, the surface of the ileum was rugged with meandering fold‐like villi. The crypts of the three segments of the small intestine were mainly coiled and sometimes branched. A novel morphometric evaluation method was introduced using the enlargement factors of each villus and crypt surface. The enlargement factor for the villus surface of the duodenum, jejunum and ileum was 3.13, 3.72 and 2.71, respectively. The factor for the crypt surface of the duodenum, jejunum and ileum was 9.07, 8.94 and 6.53, respectively. Furthermore, the relative proliferation rate and the epithelial renewal index were calculated for the first time. The relative proliferation rate of the duodenum, jejunum and ileum was 32.88, 34.78 and 50.77 proliferations per mm crypt perimeter, respectively. The diets consumed had an influence on the epithelial renewal index being higher for piglets fed the cereal‐based diets.
Umwelteinflüsse verursachten an der im Jahre 1951 errichteten Neckargartacher Brücke, die einst längste Spannbetonbrücke der Welt, nichtsanierungsfähige Schäden. Die Stadt Heilbronn beschloß daher, ...die Brücke abzureißen und in Form einer Stahlverbundbrücke neu zu erbauen. Abbruch und Neubau der Brücke erforderten eine Bauzeit von 16 Monaten und verursachten Kosten in Höhe von 6,1 Mio. DM. Am 6. Oktober 1999 konnte die Brücke für den Verkehr freigegeben werden.
During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO
) ...exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO
seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO
gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO
cycles from 48 European stations were available for 2017 and 2018. Earlier data were retrieved for comparison from international databases or national networks. Here, we show that the usual summer minimum in CO
due to the surface carbon uptake was reduced by 1.4 ppm in 2018 for the 10 stations located in the area most affected by the temperature anomaly, mostly in Northern Europe. Notwithstanding, the CO
transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO
uptake by photosynthesis and/or a reduction in respiration driven by the depletion of substrate for respiration inherited from the previous months due to the drought. For stations with sufficiently long time series, the CO
anomaly observed in 2018 was compared to previous European droughts in 2003 and 2015. Considering the areas most affected by the temperature anomalies, we found a higher CO
anomaly in 2003 (+3 ppm averaged over 4 sites), and a smaller anomaly in 2015 (+1 ppm averaged over 11 sites) compared to 2018. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
The pecten oculi is a structure peculiar to the avian eye. Three morphological types of pecten oculi are recognized: conical type, vaned type and pleated type. The pleated type has been well studied. ...However, there exists only scanty data on the morphology of the latter two types of pectens. The structure of the vaned type of pecten of the ostrich,
Struthio camelus was investigated with light and electron microscope. The pecten of this species consists of a vertical primary lamella that arises from the optic disc and supports 16–19 laterally located secondary lamellae, which run from the base and confluence at the apex. Some of the secondary lamellae give rise to 2 or 3 tertiary lamellae. The lamellae provide a wide surface, which supports 2–3 layers of blood capillaries. Pigmentation is highest at the distal ends of the secondary and tertiary lamella where blood capillaries are concentrated and very scanty on the primary and the proximal ends of the secondary lamella where the presence of capillaries is much reduced. In contrast to the capillaries of the pleated pecten, the endothelium of the capillaries in the pecten of the ostrich exhibits very few microvilli. These observations suggest that the morphology of the pecten of the ostrich, a flightless ratite bird is unique to the pleated pecten and is designed to meet the balance between optimal vision and large surface area for blood supply and yet ensuring it is kept firmly erect within the vitreous.
In vitro studies on the pathogenesis in swine have been hampered by the lack of relevant porcine cell lines. Since many bacterial infections are swine-specific, studies on pathogenic mechanisms ...require appropriate cell lines of porcine origin. We have characterized the permanent porcine intestinal epithelial cell line, IPEC-J2, using a variety of methods in order to assess the usefulness of this cell line as an in vitro infection model. Electron microscopic analyses and histochemical staining revealed the cells to be enterocyte-like with microvilli, tight junctions and glycocalyx-bound mucin. The functional integrity of monolayers was determined by transepithelial electrical resistance (TEER) measurements. Both commensal bacteria and important bacterial pathogens were chosen for study based on their principally different infection mechanisms: obligate extracellular Escherichia coli, facultative intracellular Salmonella and obligate intracellular Chlamydia. We determined the colonization and proliferation of the bacteria on and within the host cells and monitored the host cell response. We verified the expression of mRNAs encoding the cytokines IL-1alpha, -6, -7, -8, -18, TNF-alpha and GM-CSF, but not TGF-beta or MCP-1. IL-8 protein expression was enhanced by Salmonella invasion. We conclude that the IPEC-J2 cell line provides a relevant in vitro model system for porcine intestinal pathogen-host cell interactions.
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