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White asparagus is a highly appreciated, high-value crop with a distinguished economic relevance among vegetables. Freshly harvested asparagus is available only during a short part of the year and the demand varies. The produce is perishable and only proper handling can ensure its quality after a reasonable shelf life. In this study, we investigated a new method to reduce one of the most important reasons for quality decline: fresh matter losses. The potential benefits or disadvantages of moist asparagus packaging for unpeeled white asparagus (cv. 'Gijnlim') was tested. We used polythene sleeves or bags, lined with cellulose fleece to hold added water for moisturizing. 500 g bunches of spears were filled in the bags. Spears were partly covered by the sleeves or totally covered by the bags. All spears were stored for 3 to 11 days at the temperature of 2°C, 8°C and a combination of 2°C/22°C.The last temperatures were to simulate retail conditions. In wet bags spear fresh weight increased, losses in bags with dry fleece were low. Maintaining of fresh weight in wet bags coincided significantly with higher bending firmness, and lower shear force, which points to less fibrousness. Wet storage also reduced the incidence of dried cut surfaces but promoted the incidence of lengthwise fractures and, in combination with higher temperature, grey-brown discolouration and colour saturation. Wet packaging may be beneficial primarily under low temperature and low air humidity storage conditions.

Aberrant DNA methylation patterns, including hypermethylation of tumor suppressor genes, have been described in many human cancers. These epigenetic mutations can be reversed by DNA methyltransferase inhibitors, which provide novel opportunities for cancer therapy. Clinical concepts for epigenetic therapies are currently being developed by using azanucleosides for the treatment of leukemias and other tumors. These trials will greatly benefit from the inclusion of molecular markers for monitoring epigenetic changes in patients and for maximizing biologic responses. In addition, novel inhibitors need to be developed that result in a direct and specific inhibition of DNA methyltransferase activity. Several recent developments indicate that rational design of small molecule DNA methyltransferase inhibitors is feasible and that this approach can result in the establishment of novel drug candidates. The use of novel DNA methyltransferase inhibitors in clinical trials that allow monitoring of drug-induced DNA methylation changes should provide the foundation for improved epigenetic cancer therapies. [ABSTRACT FROM AUTHOR]

White asparagus is a high-value commodity of large economic importance in Germany. Its harvest period lasts only a limited part of the year, during which daily yield and also market demand are highly variable. Harvested asparagus is perishable; thus, quality control and shelf life must be ensured by proper handling, e.g., avoiding fresh weight losses and, at the same time, limiting microbial growth. The aim of this study was to determine the effect of moist asparagus packaging on unpeeled white asparagus (cv. Gijnlim). Water was added to some of the packages to reduce fresh weight losses and to study the consequences for microbial growth. Polythene bag packaging, lined inside with cellulose fleece, was used to hold 500-g bunches of spears, covered partly (open bag) or totally (closed bag). Storage duration was 7 days, at temperatures of 2°C, 8°C, and a combination of 2 and 22°C, simulating retail conditions. Using a standardized cultivation method for food assessment, CFU counts (5.20 to 7.95 log CFU), number of pseudomonads (4.79 to 7.90 log CFU), lactic acid bacteria (<3.00 to 3.94 log CFU), Enterobacteriaceae (4.26 to 7.15 log CFU, including Escherichia coli <1.00 log CFU), yeasts (<2.30 to 3.15 to 3.53 log CFU), and molds (<2.30 log CFU), as well as sulfite-reducing clostridia (<1 log CFU) were determined. Temperature was the most important factor for microbial growth. Additional water had no effect in most cases; it inhibited most of the fresh weight losses compared to dry treatments in this study but led to 2% weight increase in closed bags. Our results point to the conclusion that moist packaging would be a feasible alternative to dry wrapping with regard to weight retention, and it did not increase growth of the analyzed microbial groups to an unacceptable value.

This study is focused on the synthesis and characterization of hydroxy-apo-10'-carotenal/quantum dot (QD) conjugates aiming at the in vivo visualization of β-ionone, a carotenoid-derived volatile compound known for its important contribution to the flavor and aroma of many fruits, vegetables, and plants. The synthesis of nanoparticles bound to plant volatile precursors was achieved via coupling reaction of the QD to C27-aldehyde which was prepared from α-ionone via 12 steps in 2.4% overall yield. The formation of the QD-conjugate was confirmed by measuring its fluorescence spectrum to observe the occurrence of fluorescence resonance energy transfer.

In humans, adipose tissue is distributed in subcutaneous abdominal and subcutaneous gluteal depots that comprise a variety of functional differences. Whereas energy storage in gluteal adipose tissue has been shown to mediate a protective effect, an increase of abdominal adipose tissue is associated with metabolic disorders. However, the molecular basis of depot-specific characteristics is not completely understood yet. Using array-based analyses of transcription profiles, we identified a specific set of genes that was differentially expressed between subcutaneous abdominal and gluteal adipose tissue. To investigate the role of epigenetic regulation in depot-specific gene expression, we additionally analyzed genome-wide DNA methylation patterns in abdominal and gluteal depots. By combining both data sets, we identified a highly significant set of depot-specifically expressed genes that appear to be epigenetically regulated. Interestingly, the majority of these genes form part of the homeobox gene family. Moreover, genes involved in fatty acid metabolism were also differentially expressed. Therefore we suppose that changes in gene expression profiles might account for depot-specific differences in lipid composition. Indeed, triglycerides and fatty acids of abdominal adipose tissue were more saturated compared to triglycerides and fatty acids in gluteal adipose tissue. Taken together, our results uncover clear differences between abdominal and gluteal adipose tissue on the gene expression and DNA methylation level as well as in fatty acid composition. Therefore, a detailed molecular characterization of adipose tissue depots will be essential to develop new treatment strategies for metabolic syndrome associated complications.

Silencing of genes by hypermethylation contributes to cancer progression and has been shown to occur with increased frequency at specific genomic loci. However, the precise mechanisms underlying the establishment and maintenance of aberrant methylation marks are still elusive. The de novo DNA methyltransferase 3B (DNMT3B) has been suggested to play an important role in the generation of cancer-specific methylation patterns. Previous studies have shown that a reduction of DNMT3B protein levels induces antiproliferative effects in cancer cells that were attributed to the demethylation and reactivation of tumor suppressor genes. However, methylation changes have not been analyzed in detail yet. Using RNA interference we reduced DNMT3B protein levels in colon cancer cell lines. Our results confirm that depletion of DNMT3B specifically reduced the proliferation rate of DNMT3B-overexpressing colon cancer cell lines. However, genome-scale DNA methylation profiling failed to reveal methylation changes at putative DNMT3B target genes, even in the complete absence of DNMT3B. These results show that DNMT3B is dispensable for the maintenance of aberrant DNA methylation patterns in human colon cancer cells and they have important implications for the development of targeted DNA methyltransferase inhibitors as epigenetic cancer drugs.

The DNA methyltransferase inhibitors azacytidine and decitabine represent archetypal drugs for epigenetic cancer therapy. To characterize the demethylating activity of azacytidine and decitabine we treated colon cancer and leukemic cells with both drugs and used array-based DNA methylation analysis of more than 14,000 gene promoters. Additionally, drug-induced demethylation was compared to methylation patterns of isogenic colon cancer cells lacking both DNA methyltransferase 1 (DNMT1) and DNMT3B. We show that drug-induced demethylation patterns are highly specific, non-random and reproducible, indicating targeted remethylation of specific loci after replication. Correspondingly, we found that CG dinucleotides within CG islands became preferentially remethylated, indicating a role for DNA sequence context. We also identified a subset of genes that were never demethylated by drug treatment, either in colon cancer or in leukemic cell lines. These demethylation-resistant genes were enriched for Polycomb Repressive Complex 2 components in embryonic stem cells and for transcription factor binding motifs not present in demethylated genes. Our results provide detailed insights into the DNA methylation patterns induced by azacytidine and decitabine and suggest the involvement of complex regulatory mechanisms in drug-induced DNA demethylation.

Azacytidine is an established nucleoside drug that is well known for its ability to modulate epigenetic gene regulation by inhibition of DNA methylation. Despite recent advances in the clinical development of azacytidine, the use of the drug is limited by its low bioavailability and dependency on variably expressed nucleoside transporters for cellular uptake. We show here that CP-4200, an elaidic acid derivative of azacytidine, has strong epigenetic modulatory potency in human cancer cell lines, as evidenced by efficient depletion of DNA methyltransferase protein, genome-wide DNA demethylation, and robust reactivation of epigenetically silenced tumor suppressor genes. Importantly, however, the cellular uptake of CP-4200 was substantially less dependent on the nucleoside transporters that are known to be involved in azacytidine uptake. In agreement with this notion, CP-4200 showed a significantly higher antitumoral activity than azacytidine in an orthotopic mouse tumor model for acute lymphocytic leukemia. Together, these data represent a detailed characterization of the CP-4200 mode of action and suggest that elaidic acid modification improves the therapeutic efficacy of azacytidine.

MicroRNAs (miRNAs) are small RNA molecules that control gene expression by inhibition of protein translation or degradation of cognate target mRNAs. Eventhough strict Even though strict developmental and tissue-specific regulation appears to be critical for miRNA function, very little is known about the mechanisms governing miRNA gene expression. Several recent studies have shown that miRNA genes can regulated DNA methylation and other epigenetic mechanisms. The observation of altered miRNA gene methylation patterns in human cancers also suggested that miRNA gene methylation is functional relevant for tumorigenesis. We have now performed a comprehensive analysis of miRNA genes and found that about half of these genes are associated with CpG islands and thus represent candidate targets of the DNA methylation machinery An expanded analysis of several miRNA-associated CpG islands in five cell lines indicated that miRNA gene methylation is detectable at high frequencies, both in normal and malignant cells. Possible explanations for this phenomenon include the specific structure of miRNA genes and/or their requirement for strict expression regulation.

MicroRNAs (miRNAs) are small noncoding RNAs that repress their target mRNAs by complementary base pairing and induction of the RNA interference pathway. It has been shown that miRNA expression can be regulated by DNA methylation and it has been suggested that altered miRNA gene methylation might contribute to human tumorigenesis. In this study, we show that the human let-7a-3 gene on chromosome 22q13.31 is associated with a CpG island. Let-7a-3 belongs to the archetypal let-7 miRNA gene family and was found to be methylated by the DNA methyltransferases DNMT1 and DNMT3B. The gene was heavily methylated in normal human tissues but hypomethylated in some lung adenocarcinomas. Let-7a-3 hypomethylation facilitated epigenetic reactivation of the gene and elevated expression of let-7a-3 in a human lung cancer cell line resulted in enhanced tumor phenotypes and oncogenic changes in transcription profiles. Our results thus identify let-7a-3 as an epigenetically regulated miRNA gene with oncogenic function and suggest that aberrant miRNA gene methylation might contribute to the human cancer epigenome.

Small-molecule inhibitors of DNA methyltransferases such as RG108 represent promising candidates for cancer drug development. We report the synthesis and in vitro analysis of a biotinylated RG108 conjugate, 2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-3-(5-[3-[5-(2-oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)pentanoylamino]propoxy]-1H-indol-3-yl)propionic acid (bio-RG108), for the evaluation of interactions with DNA methyltransferase enzymes. The structural design of the chemically modified inhibitor was aided by molecular modeling, which suggested the possibility for extensive chemical modifications at the 5-position of the tryptophan moiety in RG108. The inhibitory activity of the corresponding derivative was confirmed in a cell-free biochemical assay, where bio-RG108 showed an undiminished inhibition of DNA methyltransferase activity (IC50 = 40 nM). Bio-RG108 therefore represents a suitable bioconjugate for the elucidation of inhibitory mechanisms and for the affinity purification of RG108-associated proteins.

DNA methyltransferase inhibitors represent promising new drugs for cancer therapies. The first of these compounds (5-azacytidine, Vidaza) has recently been approved as an antitumor agent, and others are presently in various stages of their preclinical or clinical development. Most of the archetypal inhibitors have been established and characterized in different experimental systems, which has thus far precluded their direct comparison. We have now established defined experimental conditions that allowed a comparative analysis of the six most widely known DNA methyltransferase inhibitors: 5-azacytidine (5-aza-CR), 5-aza-2'-deoxycytidine (5-aza-CdR), zebularine, procaine, (-)-epigallocatechin-3-gallate (EGCG), and RG108. Of these, 5-aza-CR, 5-aza-CdR, zebularine, and EGCG were found to exhibit significant cytotoxicity in human cancer cell lines. 5-aza-CdR and EGCG were also found to be genotoxic, as evidenced by the induction of micronuclei. In addition, 5-aza-CR, 5-aza-CdR, zebularine, and RG108 caused concentration-dependent demethylation of genomic DNA, whereas procaine and EGCG failed to induce significant effects. Finally, the experiments in cancer cell lines were complemented by a cell-free in vitro assay with purified recombinant DNA methyltransferase, which indicated that RG108 is the only drug capable of direct enzyme inhibition. These results show a substantial diversity in the molecular activities of DNA methyltransferase inhibitors and provide valuable insights into the developmental potential of individual drugs.