Metabolic Profiling Analysis of Liver in Landes Geese During the Formation of Fatty Liver via GC-TOF/MS

Fatty liver production results from the process of overfeeding geese, inducing a dramatic increase in de novo liver lipogenesis. To investigate the alteration of liver metabolites by overfeeding, especially lipid metabolites, and the potential pathways causing these changes, 60 Landes geese at 65 days old were raised in three groups with 20 geese per group, namely, the D0 group (free from gavage), D7 group (overfeeding for 7 days), and D25 group (overfeeding for 25 days). At 90 days old, segments of liver tissue were collected from 10 geese of each group for gas chromatography time-of-flight/mass spectrometry (GC-TOF/MS) analysis. A large number of endogenous molecules in the livers of geese were altered dramatically by overfeeding. In the livers of overfed geese, the level of oleic acid was observed to continuously increase, while the levels of phenylalanine, methyl phosphate, sulfuric acid, and 3-hydroxybenzaldehyde were decreased. The most significantly different metabolites were enriched in amino acid, lipid, and nucleotide metabolism pathways. The present study further supports the idea that Landes geese efficiently produce fatty liver, and potential biomarkers and disturbed metabolic pathways during the process of forming fatty liver were identified. In conclusion, this study might provide some insights into the underlying mechanisms of fatty liver formation.

A putative cap binding protein and the methyl phosphate capping enzyme Bin3/MePCE function in telomerase biogenesis.

Telomerase reverse transcriptase (TERT) and the noncoding telomerase RNA (TR) subunit constitute the core of telomerase. Additional subunits are required for ribonucleoprotein complex assembly and in some cases remain stably associated with the active holoenzyme. Pof8, a member of the LARP7 protein family is such a constitutive component of telomerase in fission yeast. Using affinity purification of Pof8, we have identified two previously uncharacterized proteins that form a complex with Pof8 and participate in telomerase biogenesis. Both proteins participate in ribonucleoprotein complex assembly and are required for wildtype telomerase activity and telomere length maintenance. One factor we named Thc1 (Telomerase Holoenzyme Component 1) shares structural similarity with the nuclear cap binding complex and the poly-adenosine ribonuclease (PARN), the other is the ortholog of the methyl phosphate capping enzyme (Bin3/MePCE) in metazoans and was named Bmc1 (Bin3/MePCE 1) to reflect its evolutionary roots. Thc1 and Bmc1 function together with Pof8 in recognizing correctly folded telomerase RNA and promoting the recruitment of the Lsm2-8 complex and the catalytic subunit to assemble functional telomerase.

Effect of Carbon Sources in Carotenoid Production from Haloarcula sp. M1, Halolamina sp. M3 and Halorubrum sp. M5, Halophilic Archaea Isolated from Sonora Saltern, Mexico

The isolation and molecular and chemo-taxonomic identification of seventeen halophilic archaea from the Santa Bárbara saltern, Sonora, México, were performed. Eight strains were selected based on pigmentation. Molecular identification revealed that the strains belonged to the Haloarcula, Halolamina and Halorubrum genera. Neutral lipids (quinones) were identified in all strains. Glycolipid S-DGD was found only in Halolamina sp. strain M3; polar phospholipids 2,3-O-phytanyl-sn-glycerol-1-phosphoryl-3-sn-glycerol (PG), 2,3-di-O-phytanyl-sn-glycero-1-phospho-3′-sn-glycerol-1′-methyl phosphate (PGP-Me) and sodium salt 1-(3-sn-phosphatidyl)-rac-glycerol were found in all the strains; and one unidentified glyco-phospholipid in strains M1, M3 and M4. Strains M1, M3 and M5 were selected for further studies based on carotenoid production. The effect of glucose and succinic and glutamic acid on carotenoid production was assessed. In particular, carotenoid production and growth significantly improved in the presence of glucose in strains Haloarcula sp. M1 and Halorubrum sp. M5 but not in Halolamina sp. M3. Glutamic and succinic acid had no effect on carotenoid production, and even was negative for Halorubrum sp. M5. Growth was increased by glutamic and succinic acid on Haloarcula sp. M1 but not in the other strains. This work describes for first time the presence of halophilic archaea in the Santa Bárbara saltern and highlights the differences in the effect of carbon sources on the growth and carotenoid production of haloarchaea.

The methyl phosphate capping enzyme Bin3 is a stable component of the fission yeast telomerase holoenzyme

The telomerase holoenzyme is critical for maintaining eukaryotic genome integrity. In addition to a reverse transcriptase and an RNA template, telomerase contains additional proteins that protect the telomerase RNA and promote holoenzyme assembly. Here we report that the methyl phosphate capping enzyme (MePCE) Bin3 is a stable component of the S. pombe telomerase holoenzyme. Bin3 associates with the telomerase and the U6 snRNA through an interaction with the recently described LARP7 family member Pof8, and we demonstrate that these two factors are evolutionarily linked in fungi. Our data suggest that the association of Bin3 with telomerase is independent of its methyltransferase activity, but rather that Bin3 negatively regulates TER1 levels and telomere length. Taken together, this work yields new insight into the composition, assembly, and regulation of the telomerase holoenzyme in fission yeast as well as the breadth of its evolutionary conservation.

Synthesis of 1,2,3-Triazole-Containing Furanosyl Nucleoside Analogs and Their Phosphate, Phosphoramidate or Phoshonate Derivatives as Potential Sugar Diphosphate or Nucleotide Mimetics

<p>The synthesis of a variety of novel, rather stable and potentially bioactive nucleoside analogs and nucleotide mimetics based on xylofuranose scaffolds and comprising a 1,2,3-triazole moiety as a surrogate for a nucleobase or a phosphate group is reported. Isonucleosides embodying a 3-<i>O</i>-(benzyltriazolyl)methyl moiety at C-3 were accessed by using the Cu(I)-catalyzed “click” 1,3-dipolar cycloaddition between 3-<i>O</i>-propargyl-1,2-<i>O</i>-isopropylidene-α-D-xylofuranose and benzyl azide as the key step. Related isonucleotides comprising a phosphate or a phosphoramidate moiety at C-5 were obtained via 5-<i>O</i>-phosphorylation of acetonide-protected 3-<i>O</i>-propargyl xylofuranose followed by “click” cycloaddition or by Staudinger reaction of a 5ʹ-azido <i>N</i>-benzyltriazole isonucleoside with triethyl phosphite, respectively. Hydroxy, amino- or bromomethyl triazole 5ʹ-isonucleosides were synthesized through thermal cycloaddition between 5-azido 3-<i>O</i>-benzyl/dodecyl-1,2-<i>O</i>-isopropylidene-α-D-xylofuranoses and propargyl alcohol, propargylamine or propargyl bromide, respectively. The regiochemical outcome of the cycloaddition reactions was influenced by nature of the alkyne hetero substituent (alkyne CH₂X substituent). The 5´-isonucleosides were converted into their [(xylofuranos-5-yl)triazolyl]methyl phosphate, phosphoramidate and phosphonate derivatives as prospective sugar diphosphate mimetics by an appropriate method involving treatment with diethyl phosphorochloridate or a Michaelis-Arbuzov reaction. 4-Phosphonomethyl-1-xylofuranos-5ʹ-yl triazoles were converted into 1,2-<i>O</i>-acetyl glycosyl donors and subsequently subjected to nucleosidation with uracil leading to the corresponding uracil nucleoside 5ʹ-(triazolyl)methyl phosphonates, whose structure potentially mimics that of a nucleoside diphosphate. </p> <p><b> </b></p>

Synthesis of 1,2,3-Triazole-Containing Furanosyl Nucleoside Analogs and Their Phosphate, Phosphoramidate or Phoshonate Derivatives as Potential Sugar Diphosphate or Nucleotide Mimetics

<p>The synthesis of a variety of novel, rather stable and potentially bioactive nucleoside analogs and nucleotide mimetics based on xylofuranose scaffolds and comprising a 1,2,3-triazole moiety as a surrogate for a nucleobase or a phosphate group is reported. Isonucleosides embodying a 3-<i>O</i>-(benzyltriazolyl)methyl moiety at C-3 were accessed by using the Cu(I)-catalyzed “click” 1,3-dipolar cycloaddition between 3-<i>O</i>-propargyl-1,2-<i>O</i>-isopropylidene-α-D-xylofuranose and benzyl azide as the key step. Related isonucleotides comprising a phosphate or a phosphoramidate moiety at C-5 were obtained via 5-<i>O</i>-phosphorylation of acetonide-protected 3-<i>O</i>-propargyl xylofuranose followed by “click” cycloaddition or by Staudinger reaction of a 5ʹ-azido <i>N</i>-benzyltriazole isonucleoside with triethyl phosphite, respectively. Hydroxy, amino- or bromomethyl triazole 5ʹ-isonucleosides were synthesized through thermal cycloaddition between 5-azido 3-<i>O</i>-benzyl/dodecyl-1,2-<i>O</i>-isopropylidene-α-D-xylofuranoses and propargyl alcohol, propargylamine or propargyl bromide, respectively. The regiochemical outcome of the cycloaddition reactions was influenced by nature of the alkyne hetero substituent (alkyne CH₂X substituent). The 5´-isonucleosides were converted into their [(xylofuranos-5-yl)triazolyl]methyl phosphate, phosphoramidate and phosphonate derivatives as prospective sugar diphosphate mimetics by an appropriate method involving treatment with diethyl phosphorochloridate or a Michaelis-Arbuzov reaction. 4-Phosphonomethyl-1-xylofuranos-5ʹ-yl triazoles were converted into 1,2-<i>O</i>-acetyl glycosyl donors and subsequently subjected to nucleosidation with uracil leading to the corresponding uracil nucleoside 5ʹ-(triazolyl)methyl phosphonates, whose structure potentially mimics that of a nucleoside diphosphate. </p> <p><b> </b></p>