Genome sequencing of the lizard parasite Leishmania tarentolae reveals loss of genes associated to the intracellular stage of human pathogenic species

The Leishmania tarentolae Parrot-TarII strain genome sequence was resolved to an average 16-fold mean coverage by next-generation DNA sequencing technologies. This is the first non-pathogenic to humans kinetoplastid protozoan genome to be described thus providing an opportunity for comparison with the completed genomes of pathogenic Leishmania species. A high synteny was observed between all sequenced Leishmania species. A limited number of chromosomal regions diverged between L. tarentolae and L. infantum, while remaining syntenic to L. major. Globally, >90% of the L. tarentolae gene content was shared with the other Leishmania species. We identified 95 predicted coding sequences unique to L. tarentolae and 250 genes that were absent from L. tarentolae. Interestingly, many of the latter genes were expressed in the intracellular amastigote stage of pathogenic species. In addition, genes coding for products involved in antioxidant defence or participating in vesicular-mediated protein transport were underrepresented in L. tarentolae. In contrast to other Leishmania genomes, two gene families were expanded in L. tarentolae, namely the zinc metallo-peptidase surface glycoprotein GP63 and the promastigote surface antigen PSA31C. Overall, L. tarentolae's gene content appears better adapted to the promastigote insect stage rather than the amastigote mammalian stage

Predicting Runoff for a Drinking Water Catchment in Southwest Greenland

Efterhånden som smeltevandsafstrømningen fra Grønlands gletsjere og iskapper stiger, er der et øget behov for at kvantificere denne afstrømning, for at forbedre forståelsen og give et mere nøjagtigt estimat af bidraget til den globale havniveaustigning, ændringer i havstrømme på grund af en faldende saltkoncentration og potentialet for udnyttelse af naturressourcer. 12 % af verdens gletsjere og iskapper findes langs Grønlands periferi, hvor langt størstedelen ligger i oplande med delvist isdække, uden målinger og vejrstationer til at kunne beregne smeltevandsafstrømningen. Klimamodeller har derfor en nøglerolle i at simulere og estimere mængden af smeltevand i fremtiden. Generelle cirkulationsmodeller og regionale klimamodeller har for lav opløsning til at fange terrænvariationerne i oplande med delvist isdække og kan resultere unøjagtigheder ved beregning af smeltevandsafstrømninger Denne undersøgelse fremhæver disse unøjagtigheder ved at præsentere styrker og svagheder ved flere klimamodeller; undersøgelsen validerer regionale klimamodeller på lokal skala, for at opnå afstrømning af smeltevand i mindre afvandingsområder i Grønland. Statistisk nedskalering fra 11 km til 30 m blev anvendt som et værktøj til at forbedre opløsningen på lufttemperatur og nedbørsdata i oplande med delvist isdække. Den samlede månedlige afstrømning i et afvandingsområde, i Vestgrønland, blev forudsagt frem til 2060 ved hjælp af en positiv gradedagsmodel. Med en beregnet smeltevandsafstrømning, der topper i 2040, konkluderer denne undersøgelse, at mængden af smeltevand er tilstrækkelig til kommerciel udnyttelse i de næste 40 år

Probability of Sea Ice Extent: Between Eastern Greenland and Iceland 1821-1956

Our data set includes nine probability maps of sea ice extent, available in .jpeg and shapfiles. They were created from historical maps of sea ice extent off Iceland dating back to 1877 compiled by Koch (1945) that we digitized. We use these maps in combination with sea ice charts from the Danish Meteorological Institute (DMI) and Koch's sea ice index from 1820 to 1939 to provide spatial maps of estimated sea ice extent between Iceland and Greenland back to 1821. The probability maps should be used in combination with the table: Summary of Koch's Index Years, in order to know which years fall under which category

Observationally constrained reconstruction of 19th to mid-20th century sea-ice extent off eastern Greenland

Arctic sea ice has a significant impact on the global radiation budget, oceanic and atmospheric circulation and the stability of the Greenland ice sheet (Vaughan et al. 2013). Prior to the era of aircraft and satellite, information on sea-ice extent relied on observations from ships and people living at the coast. This information is a valuable contribution to better understand the history of sea ice. However, the information exists in a range of formats, e.g., sea-ice extent before the late 1800s is typically reported in the literature as an annual index from a single geographical point or as hand-drawn maps. This makes it difficult to assess and compare data across time and space. The combination of digitised historical maps and single-point data makes the information more accessible and provides a record that can help understand the dynamics and processes of the climate and its interactions with the cryosphere (Chapman & Walsh 1993). In this study, maps of sea-ice extent by Koch (1945) were digitised. We use these maps in combination with sea-ice charts from the Danish Meteorological Institute (DMI) and Koch’s sea-ice index from 1820 to 1939, to map estimated sea-ice extent between Iceland and Greenland going back to 1821. This information has not been included in even the most recent databases of Arctic sea ice (Walsh et al. 2015, 2017). Furthermore, we extract time series of sea-ice extent at a number of locations and investigate the relationship between them. Our observation area is along eastern Greenland, between the southern tip of Greenland at 59°46´N northwards to 77°21´N