N-glycan chitobiose core biosynthesis by Agl24 strengthens the hypothesis of an archaeal origin of the eukaryal N-glycosylation

Protein N-glycosylation is the most common posttranslational modifications found in all three domains of life. The crenarchaeal N-glycosylation begins with the synthesis of a lipid-linked chitobiose core structure, identical to that in eukaryotes. Here, we report the identification of a thermostable archaeal beta-1,4-N-acetylglucosaminyltransferase, named archaeal glycosylation enzyme 24 (Agl24), responsible for the synthesis of the N-glycan chitobiose core. Biochemical characterization confirmed the function as an inverting β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol glycosyltransferase. Substitution of a conserved histidine residue, found also in the eukaryotic and bacterial homologs, demonstrated its functional importance for Agl24. Furthermore, bioinformatics and structural modeling revealed strong similarities between Agl24 and both the eukaryotic Alg14/13 and a distant relation to the bacterial MurG, which catalyze the identical or a similar process, respectively. Our data, complemented by phylogenetic analysis of Alg13 and Alg14, revealed similar sequences in Asgardarchaeota, further supporting the hypothesis that the Alg13/14 homologs in eukaryotes have been acquired during eukaryogenesis.HighlightsFirst identification and characterization of a thermostable β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol glycosyltransferase (GT family 28) in Archaea.A highly conserved histidine, within a GGH motif in Agl24, Alg14, and MurG, is essential for function of Agl24.Agl24-like homologs are broadly distributed among Archaea.The eukaryotic Alg13 and Alg14 are closely related to the Asgard homologs, suggesting their acquisition during eukaryogenesis.

Phylogenetic Study of Zebrafish (Amatitlania nigrofasciata) as an Introduction Spesies in Buyan Lake

Buyan Lake has some fishery commodities which were often encountered include the Zebrafish (Amatitlania nigrofasciata). The origin existence of Zebrafish in Buyan Lake is not yet known then it needs study in order to know the certainty of species, phylogenetic, haplotype diversity, and phenotype characteristic. The study was conducted from January to February 2018. Molecular identification was done at Laboratory of Biodiversity Indonesia Bali. This research used quantitative and qualitative descriptive methods. Sampling was done by simple random sampling from fisherman catches. Zebrafish’s fin samples were used for molecular identification and Zebrafish’s morphological for morphological identification. The results showed that the entire sequence samples were successfully amplified with the Cytochrome Oxidase subunit I (COI) gene of 620 bp. The genetic distance in the entire Zebrafish sequences in Buyan Lake of 0 which means that the sequence of all samples are exactly similiar as species of Amatitlania nigrofasciata with the genetic distance calculation of 0. Sequence of Zebrafish in Buyan Lake is closely related to Amatitlania nigrofasciata KU568740, Amatitlania nigrofasciata KU568739, Amatitlania nigrofasciata KU568737, Amatitlania nigrofasciata KJ552531, and Amatitlania nigrofasciata KU568738 with genetic distance of 0 and has a distant relation with Rocio ostofasciata EU751752 with genetic distance of 0.113. The haplotype diversity of Zebrafish sequences in Buyan Lake showed the value of 0 which belongs to a low haplotype diversity. Black and Black Zebrafish with Red Spotted are in a different clade with Albino and Albino Zebrafish with Red Spotted with bootstrap value of 100, means they have phenotypically differences.

“Bottomsets” of the lava−fed delta of James Ross Island Volcanic Group, Ulu Peninsula, James Ross Island, Antarctica

Sedimentological study of the three geographically separated outcrops of bottom− sets of a single lava−fed delta (Pliocene) in the James Ross Island (Antarctica) allows recognition of six lithofacies.Deposits of traction currents, deposits of volcaniclastic debris flows and products of such flows transformations (both low− and high−density turbidity currents) and glacigenic deposits (subaqueous debris flows and traction/turbidity currents) were all recognised. Existence of submarine proglacial environment formed prior to formation of volcani− clastic deposits partly covering the subaqueous slopes of volcano is supposed. The principal role of mass flow processes was recognised and explained by relative steep slopes of the lava−fed delta. The distribution of lithofacies significantly differs in the individual outcrops. These variations in sedimentary succession and also in thickness of volcaniclastic deposits of “bottomsets” of the single lava fed delta suggest principal role of local conditions and paleogeography for development and preservation of this part of delta depositional system. Moreover proximal and distal setting can be followed and direct vs. more distant relation to over−riding lava−fed delta supposed. The sedimentary succession terminated by foresets of hyaloclastite breccia.

Progesterone Induces Scolex Evagination of the Human ParasiteTaenia solium: Evolutionary Implications to the Host-Parasite Relationship

Taenia soliumcysticercosis is a health problem in underdeveloped and developed countries. Sex hormones are involved in cysticercosis prevalence in female and male pigs. Here, we evaluated the effects of progesterone and its antagonist RU486 on scolex evagination, which is the initial step in the development of the adult worm. Interestingly, progesterone increasedT. soliumscolex evagination and worm growth, in a concentration-independent pattern. Progesterone effects could be mediated by a novelT. soliumprogesterone receptor (TsPR), since RU486 inhibits both scolex evagination and worm development induced by progesterone. Using RT-PCR and western blot, sequences related to progesterone receptor were detected in the parasite. A phylogenetic analysis reveals that TsPR is highly related to fish and amphibian progesterone receptors, whereas it has a distant relation with birds and mammals. Conclusively, progesterone directly acts uponT. soliumcysticerci, possibly through its binding to a progesterone receptor synthesized by the parasite.

A Statuette of Eros

The interesting statuette of Eros, a photographic print of which accompanies this paper, was presented by His Majesty the King of the Hellenes to Her Royal Highness the Princess of Wales, who has been good enough to permit its publication in these pages. It is of terra-cotta, gilt, and measures 10¼ inches in height without the plinth. It is almost uninjured; but the thumb of the right hand is a restoration. At the back is the usual round air-hole.It is evident at once that we have here to do with a very unusual representation of Eros, and with one which is to most people singularly pleasing: the head in particular being very attractive. In spite of grave faults in the modelling which reveal themselves on closer inspection, it remains clear that the statuette must be derived from some notable sculptural type. On first seeing it I was at once convinced that it must stand in no distant relation to one of the celebrated statues of Eros, by Praxiteles; and subsequent study has, I hope, put me in a position to prove what was at first mere matter of surmise.