ALBERT

Description: Three new simple trichothecenes, 15-acetyltrichoverrol B ( 3 ), 13′-acetyltrichoverrin B ( 5 ), and 6′-dehydroxytrichoverrin B ( 6 ), along with five known trichothecenes trichodermadienediol B ( 1 ), trichoverrol B ( 2 ), trichoverrin B ( 4 ), and roridins A ( 7 ) and D ( 8 ), have been isolated from the liquid culture of Myrothecium roridum (strain no. QB-1). The structures of the new compounds were established by comprehensive analysis of 1D- and 2D-NMR data. All the compounds were evaluated for antifungal activity, only compounds 7 and 8 showed significant antifungal activity against the tested fungi ( MIC ranged from 10 to 5 μg/ml).

Description: . A new low-dimensional benzyl viologen/iodoargentate hybrid, [(BV) 2 (Ag 5 I 9 )] n ( 1 ) (BV 2+ = benzyl viologen) was prepared. In 1 , (Ag 6 I 9 ) n 2– chain exhibits a new type of one-dimensional chain constructed from vertex-sharing of Ag 5 I 10 units, and its two-dimensional layer structure was constructed from C–H ··· I hydrogen bonds. Strong luminescence at 404 nm can be detected in 1 . DFT calculation suggests that 1 displays a reduced bandgap, which is led by a more dispersed LUMO band of BV 2+ compared with M V 2+ in [ M V(Ag 2 I 4 )] n .

Description: Filamentous fungi-copper (Cu) interactions are very important in the formation of natural ecosystems and the bioremediation of heavy metal pollution. However, important issues at the proteome level remain unclear. We compared six proteomes from Cu-resistant wild-type (WT) Penicillium janthinellum strain GXCR and a Cu-sensitive mutant (EC-6) under 0, 0.5, and 3 mmol/L Cu treatments using iTRAQ. A total of 495 known proteins were identified, and the following conclusions were drawn from the results: Cu tolerance depends on ATP generation and supply, which is relevant to glycolysis pathway activity; oxidative phosphorylation, the TCA cycle, gluconeogenesis, fatty acid synthesis, and metabolism are also affected by Cu; high Cu sensitivity is primarily due to an ATP energy deficit; among ATP generation pathways, Cu-sensitive and Cu-insensitive metabolic steps exist; gluconeogenesis pathway is crucial to the survival of fungi in Cu-containing and sugar-scarce environments; fungi change their proteomes via two routes (from ATP, ATP-dependent RNA helicases (ADRHs), and ribosome biogenesis to proteasomes and from ATP, ADRHs to spliceosomes and/or stress-adapted RNA degradosomes) to cope with changes in Cu concentrations; and unique routes exist through which fungi respond to high environmental Cu. Further, a general diagram of Cu-responsive paths and a model theory of high Cu are proposed at the proteome level. Our work not only provides the potential protein biomarkers that indicate Cu pollution and targets metabolic steps for engineering Cu-tolerant fungi during bioremediation but also presents clues for further insight into the heavy metal tolerance mechanisms of other eukaryotes. Our work not only provides the potential protein biomarkers indicating the Cu pollution, target metabolic steps for engineering the Cu-tolerant fungi during bioremediation, but also presents clues for insight into heavy metal tolerance mechanisms of other eukaryotes.

Description: Five years of atmospheric temperature data, collected with an Fe Boltzmann lidar by the University of Colorado group from 2011 to 2015 at Arrival Heights, are used to characterize the vertical wavelengths, periods, vertical phase speeds, frequency spectra, and vertical wavenumber spectra of stratospheric gravity waves from 30–50 km altitudes. Over 1000 dominant gravity wave events are identified from the data. The seasonal spectral distributions of vertical wavelengths, periods, and vertical phase speeds in summer, winter, and spring/fall are found obeying a lognormal distribution. Both the downward and upward phase progression gravity waves are observed by the lidar, and the fractions of gravity waves with downward phase progression increase from summer ~59% to winter ~70%. The seasonal and monthly mean vertical wavelengths and periods exhibit clear seasonal cycles with vertical wavelength growing from summer ~5.5 km to winter ~8.5 km, and period increasing from summer ~4.5 h to winter ~6 h. Statistically significant linear correlations are found between the monthly mean vertical wavelengths/periods and the mean zonal wind velocities from 30–50 km. Assuming horizontal phase speeds independent of month, the monthly mean horizontal wavelengths, intrinsic periods, and group velocities are estimated for stratospheric gravity waves. The slopes of wave frequency spectra change from -1.9 at 30–60 km to -1.45 around 60–65 km. The vertical wavenumber spectra show the power spectral density at vertical wavelengths of 5–20 km decreasing from winter maximum to summer minimum. Several aforementioned features are observed for the first time in Antarctica.

Description: The regulation of human microRNA (miRNA) expression is still poorly understood and aberrant epigenetic regulation has recently been implicated in the down-regulation of tumor suppressor miRNAs. In this study, we investigated whether histone modifications would contribute to the dysregulation of miRNAs in lymphoblastic leukemia cells. Using a precursor B-cell acute lymphoblastic leukemia cell line, NALM-6 cells, we demonstrated by miRNA microarray analysis that a specific histone deacetylases inhibitor, trichostatin A (TSA), induced a differential alteration in cellular miRNA expression. A total of 10 miRNAs were down-regulated and 31 up-regulated significantly following TSA treatment. Among TSA-up-regulated miRNAs, miR-22 is an extronic miRNA and resides in the second exon of the non-coding transcript MGC14376. Up-regulation of both miR-22 and MGC14376 was found in NALM-6 cells treated with TSA but not 5-AZA-2’-deoxycytidine, a DNA demethylating agent. Luciferase reporter analysis identified three regions in the promoter of miR-22 and MGC14376 that differentially regulated its transcriptional activation. Although there is a CpG island within the promoter of miR-22 and MGC14376, no obvious methylation was detected at this region in NALM-6 cells. Conversely, H3K27 trimethylation (H3K27triM)-associated histone modification was identified in the first intron of MGC14376 gene and was involved in TSA-induced miR-22 expression. Thus, miR-22 silencing in NALM-6 cells involves H3K27triM-associated histone modification but is independent of DNA methylation, suggesting that methylation-independent H3K27triM histone modification may be an important mechanism for miRNA dysregulation in cancer cells.

Description: Abstract 3621 Increasing evidence suggests that dysregulation of miRNAs plays an important pathological role in various malignant diseases including acute leukemia. To reveal the contributions of aberrant epigenetic modifications to the deregulated miRNA expression in precursor B-cell acute lymphoblastic leukemia, we examined the miRNA expression profile in NALM-6 cells after treatment with the combination of 5-AZA-2'-deoxycytidine (AZA) and trichostatin A (TSA). We found that the treatment significantly increased expression of 34 miRNAs and decreased the expression of 10 miRNAs. One of the most significantly upregulated miRNAs is miR-218, an intronic miRNA that can be transcribed from either pri-miR-218-1 or pri-miR-218-2, residing in the intron of the SLIT2 gene or SLIT3 gene respectively. Interestingly, we detected that pri-miR-218-1 and its host gene SLIT2, but not pri-miR-218-2 and SLIT3, were induced by AZA plus TSA treatment. Consistent with this observation, we showed that the CpG islands in SLIT2 promoter was highly methylated in NALM-6 cells and AZA plus TSA treatment significantly decreased DNA methylaiton in this region. We found that targeting of the 3'untranslated region of CDK6, a bona fide oncogenic factor, by miR-218 resulting in translational repression. Overexpression of miR-218 expression in NALM-6 cells by transfection of miR-218 precursor decreased cellular expression of CDK6 at the protein level, but not at the message level. AZA and TSA treatment decreased CDK6 expression in NALM-6 cells, presumably through upregulating miR-218. Our results indicate that epigenetic regulation plays an important role in controlling miRNA expression in human acute lymphoblastic leukemia cells. Epigenetic silencing of miR-218 may contribute to the overexpression of CDK6 in NALM-6 cells. Disclosures: No relevant conflicts of interest to declare.

Description: All-trans-retinoic acid (ATRA) induces growth inhibition, differentiation, and apoptosis in cancer cells, including acute promyelocytic leukemia (APL). In APL, expression of promyelocytic leukemia protein retinoic acid receptor–α (PML-RARα) fusion protein, owing to the t(15; 17) reciprocal translocation, leads to a block in the promyelocytic stage of differentiation. Here, we studied molecular mechanisms involved in ATRA-induced growth inhibition and myeloid cell differentiation in APL. By employing comprehensive high-throughput proteomic methods of 2-dimensional (2-D) gel electrophoresis and amino acid–coded mass tagging coupled with electrospray ionization (ESI) mass spectrometry, we systematically identified a total of 59 differentially expressed proteins that were consistently modulated in response to ATRA treatment. The data revealed significant down-regulation of eukaryotic initiation and elongation factors, initiation factor 2 (IF2), eukaryotic initiation factor 4AI (eIF4AI), eIF4G, eIF5, eIF6, eukaryotic elongation factor 1A-1 (eEF1A-1), EF-1-δ, eEF1γ, 14-3-3ϵ, and 14-3-3ζ/δ (P 〈 .05). The translational inhibitor DAP5/p97/NAT1 (death-associated protein 5) and PML isoform-1 were found to be up-regulated (P 〈 .05). Additionally, the down-regulation of heterogeneous nuclear ribonucleoproteins (hnRNPs) C1/C2, UP2, K, and F; small nuclear RNPs (snRNPs) D3 and E; nucleoprotein tumor potentiating region (TPR); and protein phosphatase 2A (PP2A) were found (P 〈 .05); these were found to function in pre-mRNA processing, splicing, and export events. Importantly, these proteomic findings were validated by Western blot analysis. Our data in comparison with previous cDNA microarray studies and our reverse transcription–polymerase chain reaction (RT-PCR) experiments demonstrate that broad networks of posttranscriptional suppressive pathways are activated during ATRA-induced growth inhibition processes in APL.

Description: Abstract 3464 Poster Board III-352 MicroRNA-22 is one of the miRNAs frequently downregulated in human ALL cells and may play an important anti-tumor role in normal hematopoiesis. Histone modification and DNA methylation can have different roles in gene silencing in cancer. To investigate whether histone modifications would contribute to the dysregulation of miRNA-22 in acute lymphoblastic leukemia (ALL), the effect of a histone deacetylase inhibitor, trichostatin A (TSA), on miRNA-22 expression of primary ALL cells was analyzed by real-time PCR. The total number of patients included to this study is 33, including 26 samples of leukemia (18 of ALL and 8 of acute myeloid leukemia) and 7 normal controls. All patient blood samples were collected at the time of diagnosis. We detected a lower expression of pri-miR-22 in PMBCs from ALL patients compared with that from the health volunteers. Treatment with TSA significantly increased pri-miR-22 expression in PMBCs from ALL patients, but not in cells from the health volunteers. Whereas PMBCs from ALL patients and AML patients showed comparable levels of pri-miR-22. TSA treatment had no effect on pri-miR-22 expression in PMBCs from AML patients, suggesting TSA-mediated upregulation of miR-22 transcription in ALL but not AML malignant cells. Moreover, we used MPS assay to analyze the methylation status at the promoter element of miR-22 gene in primary human specimens. No DNA hypermethylation was detected in PMBCs from the health volunteers and patients with either ALL or AML. These data provide further evidence that miR-22 silencing in ALL cells may be DNA methylation-independent. In contrast, accumulation of the repressive histone marker H3K27 trimethylation (H3K27triM) was indentified around the transcriptional start point of the gene, which reduced by TSA treatment. In conclusion, we showed that histone modification is involved in miRNA dysregulation in human ALL cells. Specifically, the silencing of miR-22 in ALL cells is associated with the accumulation of histone modification in its promoter element of miR-22 gene but independent of DNA methylation. The accumulation of H3K27triM may be a novel epigenetic mechanism for miR-22 silencing in ALL. Disclosures No relevant conflicts of interest to declare.