9 research outputs found
Supplement from Export of ice nucleating particles from watersheds: results from the Amazon and Tocantins River Plumes
Numerical data shown in Figure 2 of the manuscript
N and O Isotope Fractionation in Nitrate during Chemolithoautotrophic Denitrification by <i>Sulfurimonas gotlandica</i>
Chemolithoautotrophic
denitrification is an important mechanism of nitrogen loss in the
water column of euxinic basins, but its isotope fractionation factor
is not known. <i>Sulfurimonas gotlandica</i> GD1<sup>T</sup>, a recently isolated bacterial key player in Baltic Sea pelagic
redoxcline processes, was used to determine the isotope fractionation
of nitrogen and oxygen in nitrate during denitrification. Under anoxic
conditions, nitrate reduction was accompanied by nitrogen and oxygen
isotope fractionation of 23.8 ± 2.5‰ and 11.7 ± 1.1‰,
respectively. The isotope effect for nitrogen was in the range determined
for heterotrophic denitrification, with only the absence of stirring
resulting in a significant decrease of the fractionation factor. The
relative increase in δ<sup>18</sup>O<sub>NO3</sub> to δ<sup>15</sup>N<sub>NO3</sub> did not follow the 1:1 relationship characteristic
of heterotrophic, marine denitrification. Instead, δ<sup>18</sup>O<sub>NO3</sub> increased slower than δ<sup>15</sup>N<sub>NO3,</sub> with a conserved ratio of 0.5:1. This result suggests that the periplasmic
nitrate reductase (Nap) of <i>S. gotlandica</i> strain GD1<sup>T</sup> fractionates the N and O in nitrate differently than the
membrane-bound nitrate reductase (Nar), which is generally prevalent
among heterotrophic denitrifiers and is considered as the dominant
driver for the observed isotope fractionation. Hence in the Baltic
Sea redoxcline, other, as yet-unidentified factors likely explain
the low apparent fractionation
Detection of third-generation cephalosporin-resistant Enterobacteriaceae in returning soldiers.
<p>Detection of third-generation cephalosporin-resistant Enterobacteriaceae in returning soldiers.</p
Detection of third-generation cephalosporin-resistant Enterobacteriaceae per year and yearly percentage of respective detections.
<p>Detection of third-generation cephalosporin-resistant Enterobacteriaceae per year and yearly percentage of respective detections.</p
Detection of enteric colonization with third-generation cephalosporin-resistant Enterobacteriaceae in returned soldiers and previously reported detection rates in selected African and Asian countries (in alphabetic order).
<p>Detection of enteric colonization with third-generation cephalosporin-resistant Enterobacteriaceae in returned soldiers and previously reported detection rates in selected African and Asian countries (in alphabetic order).</p
Comparison of trypanosome survival times in cerebrospinal-fluid and/or HMI-9 medium.
<p>AnTat1.1 was isolated 11 days <i>p.i.</i> from rat blood, separated from blood cells and adjusted to a cell density of 5*10<sup>4</sup> parasites in 100 µl of the respective solution. Contamination of csf with blood did not exceed 20%, as judged from the erythrocyte count. <i>Rattus norvegicus</i> csf supported survival of the parasites only for some 30 hours (▴) and could not be prolonged by supplementing 33 mM glucose (data not shown). However, in a mixture of csf and HMI-9 medium (1∶1), trypanosomes survived significantly longer (i.e. approx. 45 h, ▪). As HMI-9 medium (<b>♦</b>) contains all nutrients in excess, it supports growth of trypanosomes for approximately 56 h, even if diluted with saline solution (1∶1, X).</p
Electron micrographs showing the location of trypanosomes more than 20 days after blood infection.
<p><b>a,</b> Trypanosomes (T) are in close proximity to pial cells (PC) within the subarachnoid space (SAS); BP brain parenchyma. <b>b,</b> Trypanosomes (T) are located intimately between pial cells (PC) at the intersection between subarachnoid space and <i>pia mater</i>. <b>c,</b> Area of the <i>pia mater</i> containing densly packed trypanosomes between pial cells. A, astroglial endfeet forming the <i>glia limitans</i>; SAS, subarachnoid space. <b>d,</b> Detail of c. Astrocytes (A) forming the <i>glia limitans</i> (lower line of vertical arrows). The upper line of vertical arrows marks the mesothelium. The horizontal arrow labels a tight junction between two pial cells. Trypanosomes (T) are seen between pial cells. <b>e, </b><i>Glia limitans</i> (labelled by two arrows) marks the border between brain parenchyma (BP) and <i>pia mater</i> (PM); A, foot of an astrocyte. In this image trypanosomes (T) are located within the dilated <i>glial limitans</i> (asterisks). <b>f,</b> A trypanosome located between pial cells (PC). The two arrows point to the two flagella proving that the parasites are capable of cell division at this location.</p
Changes of trypanosomal morphology during the course of infection.
<p><b>a,</b> Scanning electron micrographs of typical stumpy, intermediate and slender form trypanosomes. The size of the pictured trypanosome is 17 µm, 22 µm and 26 µm, respectively. <b>b,</b> Blood samples of 3 infected rats were analyzed for trypanosome titer up to 20 days (♦ [cells/ml]), shown is a representative curve. Additionally, the overall length of the parasites (n = 27) was measured and grouped into stumpy forms (up to 17 µm), intermediate forms (17–23 µm) and slender forms (longer than 23 µm). Intermediate forms (▪ [%]) represent proliferating trypanosomes. Slender forms (▴ [%]) increase continuously at low level during the course of infection and reach up to 40% after 20 days <i>p.i</i>. Distribution of stumpy forms is not explicitly shown but can be calculated as the difference to 100%. <b>c,</b> Comparison of trypanosomes isolated from blood or brain of infected rats. AnTat1.1 has been isolated from rat blood (4 days <i>p.i.</i>, red bars) and rat brain (35 days <i>p.i.</i>, blue bars). The overall length of parasites (n = 96) was measured from the back of the trypanosome to the tip of the flagellum (see inset). We here show that the brain isolate contains a significant amount of trypanosomes longer than 23 µm.</p
Electron micrographs showing the distribution of trypanosomes in the choroid plexus and ventricle system more than 20 days after a blood infection.
<p><b>a,</b> A representative micrograph showing a trypanosome (T) within the lumen (L) of a brain microvessel; no trypanosomes were found beyond the blood-brain barrier within the brain parenchyma (BP). <b>b,</b> Cross-section of the choroid plexus showing a fenestrated blood vessel (fV) and trypanosomes (T) within lumen and stroma (S); E, erythrocyte. Trypanosomes inside the blood vessel contain the VSG coat, while parasites in stroma are naked. <b>c,</b> Trypanosomes (T) in the stroma (S) between fenestrated capillaries (fV) containing the VSG surface coat. Note: in Figs a–c the brain was directly fixed by perfusion with glutaraldhyde prior to isolation. <b>d,</b> A trypanosome (T) inside a plexus cell within a lysosome suggesting phagocytosis of coatless trypanosomes. Trypanosomal and lysosomal membranes are labelled by double arrows. <b>e,</b> Low magnification of a choroid plexus showing the ventricle (V), plexus epithelial cells (PEC) and, in the stroma, a fenestrated capillary (fV) with a trypanosome (T). KC = Kolmer cell. <b>f,</b> Detail of the apical region of a plexus epithelial cell showing two trypanosomes (T) in close proximity of the microvilli of an epithelial cell and a Kolmer cell (KC), respectively.</p