4 research outputs found
Integrating Folktales in Archaeological Investigations: A Study from Sikkim-Darjeeling Himalayas
No full textThe study probes into archaeological exploration carried out in two places — Daramdin and Samanden in the Sikkim-Darjeeling Himalayas. The site of exploration is selected based on place names mentioned in the folktales of the Lepchas. In this regard, two folktales are considered – Rumlyang Tungrong, which is premised in Daramdin, Sikkim and the legend of Sokpa Dhunga in Samanden, Darjeeling. Investigations evinced finds of potsherds strewn across the terraces of Daramdin and an erected stone in Samanden. As for the analysis of pottery sherds, the data set collected exhibited limitations in strength, due to which scientific analytical techniques like XRD and EDX were employed to understand the provenance and pottery production methods. Meanwhile, for the erected stone in Samanden, the material manifestation of the folktale allowed us to discuss the efficacy of the folktales in aiding investigations in finding potential archaeological sites
Author's personal copy Leishmania donovani lacking the Golgi GDP-Man transporter LPG2 exhibit attenuated virulence in mammalian hosts
No full texta b s t r a c t Surface phosophoglycans such as lipophosphoglycan (LPG) or proteophosphoglycan (PPG) and glycosylinositol phospholipids (GIPLs) modulate essential interactions between Leishmania and mammalian macrophages. Phosphoglycan synthesis depends on the Golgi GDP-mannose transporter encoded by LPG2. LPG2-null (lpg2 À ) Leishmania major cannot establish macrophage infections or induce acute pathology, whereas lpg2 À Leishmania mexicana retain virulence. lpg2 À Leishmania donovani has been reported to survive poorly in cultured macrophages but in vivo survival has not been explored. Herein we discovered that, similar to lpg2 À L. major, lpg2 À L. donovani promastigotes exhibited diminished virulence in mice, but persisted at consistently low levels. lpg2 À L. donovani promastigotes could not establish infection in macrophages and could not transiently inhibit phagolysosomal fusion. Furthermore, lpg2 À promastigotes of L. major, L. donovani and L. mexicana were highly susceptible to complement-mediated lysis. We conclude that phosphoglycan assembly and expression mediated by L. donovani LPG2 are important for promastigote and amastigote virulence, unlike L. mexicana but similar to L. major. Published by Elsevier Inc
A synthetic biology approach to probing nucleosome symmetry [preprint]
No full textFull author list omitted for brevity. For the full list of authors, see article.The repeating subunit of chromatin, the nucleosome, includes two copies of each of the four core histones, and several recent studies have reported that asymmetrically modified nucleosomes occur at regulatory elements in vivo. To probe the mechanisms by which histone modifications are read out, we designed an obligate pair of H3 heterodimers, termed H3X and H3Y, which we validated genetically and biochemically. Comparing the effects of asymmetric histone tail point mutants with those of symmetric double mutants revealed that a single methylated H3K36 per nucleosome was sufficient to silence cryptic transcription in vivo. We also demonstrate the utility of this system for analysis of histone modification crosstalk, using mass spectrometry to separately identify modifications on both H3 molecules within asymmetric nucleosomes. The ability to generate asymmetric nucleosomes in vivo provides a powerful tool to probe the mechanism by which H3 tails are read out by effector proteins in the cell
