Effect of Slightly Acidic Electrolyzed Water on Chlorophyll Degradation in Postharvest Broccoli

To explore the effect of slightly acidic electrolyzed water (SAEW) on chlorophyll degradation in postharvest broccoli, the pattern of changes in the color, total chlorophyll content, chlorophyll derivative content, chlorophyll degrading enzyme activities, and key chlorophyll metabolism-related gene expression of postharvest broccoli after treatment with 50 mg/L SAEW was analyzed. The results showed that SAEW treatment could effectively slow down the degradation of total chlorophyll, maintain the contents of chlorophyll derivatives chlorophyll a, chlorophyll b, chlorophyllide a, chlorophyllide b, pheophorbide a, and pheophytin a, and delay the increase in the activities of chlorophyll metabolizing enzymes, Mg-dechelatase, pheophytinase, and pheophorbide an oxygenase in postharvest broccoli. Meanwhile, it significantly inhibited the expression of the genes encoding chlorophyll b reductase, chlorophyllase 1, chlorophyllase 2, chlorosis protein, pheophytinase, pheophorbide an oxygenase, red chlorophyll catabolite reductase, and aging specific cysteine protease, thereby allowing color protection and freshness preservation. In conclusion, SAEW can be used as an effective method to delay postharvest chlorophyll degradation and inhibit yellowing and senescence in broccoli

Separation and Identification of Anthocyanin Extracted from Mulberry Fruit and the Pigment Binding Properties toward Human Serum Albumin

Purple pigments were isolated from mulberry extracts using preparative high-speed countercurrent chromatography (HSCCC) and identified by ESI-MS/MS and high performance liquid chromatography (HPLC) techniques. The solvent system containing methyl <i>tert</i>-butyl ether, 1-butanol, acetonitrile, water, and trifluoroacetic acid (10:30:10:50:0.05; %, v/v) was developed in order to separate anthocyanins with different polarities. Cyanidin 3-<i>O</i>-(6″-<i>O</i>-α-rhamnopyranosyl-β-galactopyranoside) (also known as keracyanin) is the major component present in mulberry (41.3%). Other isolated pigments are cyanidin 3-<i>O</i>-(6″-<i>O</i>-α-rhamnopyranosyl-β-glucopyranoside) and petunidin 3-<i>O</i>-β-glucopyranoside. The binding characteristics of keracyanin with human serum albumin (HSA) were investigated by fluorescence and circular dichroism (CD) spectroscopy. Spectroscopic analysis reveals that HSA fluorescence quenched by keracyanin follows a static mode. Binding of keracyanin to HSA mainly depends on van der Waals force or H-bonds with average binding distance of 2.82 nm. The results from synchronous fluorescence, three-dimensional fluorescence, and CD spectra show that adaptive structure rearrangement and decrease of α-helical structure occur in the presence of keracyanin

Flexible TAM requirement of TnpB enables efficient single-nucleotide editing with expanded targeting scope

Abstract TnpBs encoded by the IS200/IS605 family transposon are among the most abundant prokaryotic proteins from which type V CRISPR-Cas nucleases may have evolved. Since bacterial TnpBs can be programmed for RNA-guided dsDNA cleavage in the presence of a transposon-adjacent motif (TAM), these nucleases hold immense promise for genome editing. However, the activity and targeting specificity of TnpB in homology-directed gene editing remain unknown. Here we report that a thermophilic archaeal TnpB enables efficient gene editing in the natural host. Interestingly, the TnpB has different TAM requirements for eliciting cell death and for facilitating gene editing. By systematically characterizing TAM variants, we reveal that the TnpB recognizes a broad range of TAM sequences for gene editing including those that do not elicit apparent cell death. Importantly, TnpB shows a very high targeting specificity on targets flanked by a weak TAM. Taking advantage of this feature, we successfully leverage TnpB for efficient single-nucleotide editing with templated repair. The use of different weak TAM sequences not only facilitates more flexible gene editing with increased cell survival, but also greatly expands targeting scopes, and this strategy is probably applicable to diverse CRISPR-Cas systems

BCR-ABL triggers a glucose-dependent survival program during leukemogenesis through the suppression of TXNIP

Abstracts Imatinib is highly effective in the treatment of chronic myelogenous leukemia (CML), but the primary and acquired imatinib resistance remains the big hurdle. Molecular mechanisms for CML resistance to tyrosine kinase inhibitors, beyond point mutations in BCR-ABL kinase domain, still need to be addressed. Here, we demonstrated that thioredoxin-interacting protein (TXNIP) is a novel BCR-ABL target gene. Suppression of TXNIP was responsible for BCR-ABL triggered glucose metabolic reprogramming and mitochondrial homeostasis. Mechanistically, Miz-1/P300 complex transactivates TXNIP through the recognition of TXNIP core promoter region, responding to the c-Myc suppression by either imatinib or BCR-ABL knockdown. TXNIP restoration sensitizes CML cells to imatinib treatment and compromises imatinib resistant CML cell survival, predominantly through the blockage of both glycolysis and glucose oxidation which results in the mitochondrial dysfunction and ATP production. In particular, TXNIP suppresses expressions of the key glycolytic enzyme, hexokinase 2 (HK2), and lactate dehydrogenase A (LDHA), potentially through Fbw7-dependent c-Myc degradation. In accordance, BCR-ABL suppression of TXNIP provided a novel survival pathway for the transformation of mouse bone marrow cells. Knockout of TXNIP accelerated BCR-ABL transformation, whereas TXNIP overexpression suppressed this transformation. Combination of drug inducing TXNIP expression with imatinib synergistically kills CML cells from patients and further extends the survival of CML mice. Thus, the activation of TXNIP represents an effective strategy for CML treatment to overcome resistance