Angucyclinones with IDO and TDO inhibitory activities isolated from the actinomycetes Umezawaea beigongshangensis.

Four previously undescribed angucyclinones umezawaones A-D (1-4) were isolated from the liquid cultures of Umezawaea beigongshangensis. Their structures were determined by spectroscopic analyses, single crystal X-ray diffraction, quantum chemical 13C NMR and electronic circular dichroism calculations. All compounds displayed strong inhibitory activities against indoleamine 2,3-dioxygenase and tryptophan-2,3-dioxygenase in enzymatic assay, especially compound 2.

Effect of Deep Dormancy Temperature Cultivation on Meat Quality of Crucian Carp (Carassius auratus).

To extend the survival of crucian carp (Carassius auratus) during transportation, the effect of deep dormancy temperature (DDT) cultivation on the crucian carp was investigated by measuring the respiratory rate, survival time, and effect of cooling speed on the meat quality. The results of the respiratory rate and survival time indicated that the DDT of the crucian carp was 1.6 °C. The cooling speed had a significant (p < 0.05) influence on the quality of the crucian carp meat, with a faster cooling speed resulting in a lower pH, L* value, a* value, gumminess, springiness, cohesiveness, stickiness, chewiness, CMP, and UMP content for the crucian carp meat, thus resulting in a lower sensory score for the crucian carp meat. A possible reason for the decrease in the quality of the crucian carp meat is that the faster cooling speed led to a strong stress response and higher anaerobic metabolism in the crucian carp. This can be supported by the contents of the blood glucose and lactic acid in the crucian carp treated with higher cooling speed being significantly (p < 0.05) higher than that of the control. Combining all the results of the cooling speed on the eating quality of the crucian carp meat, a cooling speed of 2 °C/h followed by 1 °C/h was suggested for the survival of crucian carp in transit.

Effect of 4 °C and ice temperature on umami-enhancing nucleotides of conditioned pork.

To study new methods to delay the umami taste attenuation of the conditioned pork, the ice temperature of pork, the content of nucleotides, lactic acid, pyruvate, glycogen, and activity of key endogenous enzymes were determined for the conditioned pork stored at 4 °C and ice temperature. The results indicated that the ice temperature of the pork ham bicipital muscle was -1.4 °C. The content of umami-enhancing nucleotides in pork stored at 4 °C decreased significantly (p < 0.05) with increasing aging time, but all umami-enhancing nucleotides in pork stored at ice temperature were decreased significantly (p < 0.05), but the decrease rates were lower than those in pork stored at 4 °C. A possible reason for this was that the storage temperature influenced the activity of endogenous enzymes and glycolysis. Ice temperature storage was an effective method to inhibit the decrease in umami taste nucleotides in conditioned pork.

Characterization of umami compounds in bone meal hydrolysate.

The objective of this research was to identify and characterize the chemical compounds that exhibited monosodium glutamate (MSG)-like taste in the hydrolyzed bone meal produced by using flavourzyme. The free amino acids and peptides in the bone meal hydrolysate were analyzed. The results showed that the glutamic acid and the aspartic acid in the bone meal increased by 13.1 times and 14.2 times, respectively, after the flavourzyme hydrolysis. The peptides' isolation identified six MSG-like peptides in the hydrolysate, including APGPVGPAG, DAINWPTPGEIAH, FLGDEETVR, GVDEATIIEILTK, PAGPVGPVG, and VAPEEHPTL, which should contribute to the taste. The human sensory evaluation results indicated that the six peptides showed MSG-like taste, and the electronic tongue analysis indicated that the six peptides showed sourness, saltiness, bitterness, and astringency. The findings of this study demonstrated that the MSG-like taste of the bone meal hydrolysate should be attributed to the generation of MSG-like amino acids and peptides from the flavourzyme hydrolysis. PRACTICAL APPLICATION: The manuscript describes the umami compounds in the bone meal hydrolysate. The findings from this study should further confirm the feasibility of using bone meal to prepare meat-flavor essence and provide a better understanding of preparing bio-source flavoring peptides, which is very important to the artificial meat development and gene breeding.

Naphthacemycins from a Streptomyces sp. as Protein-Tyrosine Phosphatase Inhibitors.

Nine new naphthacemycins (1-9), along with one known naphthacemycin (10) were isolated from the culture of Streptomyces sp. N12W1565. Their structures were elucidated on the basis of spectroscopic analysis, including UV, NMR, and HRESIMS. All the compounds showed significant activity, with IC50 values less than 10 µM against protein-tyrosine phosphatase 1B (PTP1B). The anti-PTP1B structure-activity relationship of naphthacemycins (1-10) is discussed. These findings provide a promising starting point for the development of naphthacemycins as potential anti-PTP1B agents.

Discovery of naphthacemycins as a novel class of PARP1 inhibitors.

Poly (ADP-ribose) polymerase-1 (PARP-1) is an abundant nuclear protein that plays important roles in a variety of nuclear processes, and it has been proved a prominent target in oncology for its key function in DNA damage repair. In this study, we discovered a series of naphthacemycins as a new class of PARP1 inhibitors from a microbial metabolites library via high-throughput screening. Compound I, one of this series of compounds, could reduce cellular poly (ADP-ribose) level, trap PARP1 on the damaged DNA and elevate the level of γ-H2AX, and showed the selective cytotoxicity against BRCA1-deficient cell line. Our study provided a potential scaffold for the development of new PARP1 inhibitors in cancer therapy.