Identification and characterization of a novel antioxidant peptide from feather keratin hydrolysate

Objectives

To improve the potential value of feather, which is a valuable protein resource, we have separated and identified antioxidant peptide(s) from feather hydrolysate.

Results

Feather hydrolysate was prepared by fermentation with Bacillus subtilis S1–4. Antioxidative peptides were separated by sequential acid precipitation, cation exchange, and reversed-phase fast performance liquid chromatography. Finally, a peptide with antioxidative activity was identified as Ser-Asn-Leu-Cys-Arg-Pro-Cys-Gly by MALDI time-of-flight (TOF)/TOF analysis, and determined to represent a portion of feather keratin near its N-terminal. A synthesized peptide with the same sequence was used to characterize its antioxidative properties, including scavenging free radicals, reducing power, and Fe²⁺ chelation. In terms of the peptide’s amino acid composition, the antioxidative activity might be mainly attributed to Cys and other amino acid residues.

Conclusion

Feather keratin is a good source for the quantitative preparation of antioxidative peptides.

     

Calcium regulates glutamate dehydrogenase and poly-γ-glutamic acid synthesis in <Emphasis Type="Italic">Bacillus natto</Emphasis>

Objective

To study the effect of Ca²⁺ on glutamate dehydrogenase (GDH) and its role in poly-γ-glutamic acid (γ-PGA) synthesis in Bacillus natto HSF 1410.

Results

When the concentration of Ca²⁺ varied from 0 to 0.1 g/l in the growth medium of B. natto HSF 1410, γ-PGA production increased from 6.8 to 9.7 g/l, while GDH specific activity and NH₄Cl consumption improved from 183 to 295 U/mg and from 0.65 to 0.77 g/l, respectively. GDH with α-ketoglutarate as substrate primarily used NADPH as coenzyme with a K _m of 0.08 mM. GDH was responsible for the synthesis of endogenous glutamate. The specific activity of GDH remained essentially unchanged in the presence of CaCl₂ (0.05–0.2 g/l) in vitro. However, the specific activity of GDH and its expression was significantly increased by CaCl₂ in vivo. Therefore, the regulation of GDH and PGA synthesis by Ca²⁺ is an intracellular process.

Conclusion

Calcium regulation may be an effective approach for producing γ-PGA on an industrial scale.

     

The importance of stem cell engineering in head and neck oncology

Head and neck squamous cell carcinoma is the sixth leading cause of cancer worldwide. The most common risk factors are carcinogens (tobacco, alcohol), and infection of the human papilloma virus. Surgery is still considered as the treatment of choice in case of head and neck cancer, followed by a reconstructive surgery to enhance the quality of life in the patients. However, the widespread use of artificial implants does not provide appropriate physiological activities and often cannot act as a long-term solution for the patients. Here we review the applicability of multiple stem cell types for tissue engineering of cartilage, trachea, vocal folds and nerves for head and neck injuries. The ability of the cells to self-renew and maintain their pluripotency state makes them an attractive tool in tissue engineering.     

Rapid and efficient degradation of bisphenol A by chloroperoxidase from <Emphasis Type="Italic">Caldariomyces fumago</Emphasis>: product analysis and ecotoxicity evaluation of the degraded solution

Objectives

To degrade enzymatically bisphenol A (BPA) that causes serious environmental concerns and is difficult to be degraded by chemical or physical methods.

Results

BPA (150 mg l^?1) was completely degraded by chloroperoxidase (CPO)/H₂O₂ within 7 min at room temperature, atmospheric pressure with the enzyme at 6 μg CPO ml^?1. The degradation products were identified by HPLC–MS, which suggested involvement of multiple steps. Enzymatic treatment followed by existing bioremediation technologies (activated sludge) enhanced removal of COD from 9 to 54 %. Using an ecotoxicity evaluation with Chlorella pyrenoidosa, the degradation products had a lower toxicity than BPA.

Conclusion

BPA can be degraded rapidly and efficiently under mild conditions with chloroperoxidase at 6 μg ml^?1. The degradation products had a lower toxicity than BPA.

     

PCI-24781 can improve in vitro and in vivo developmental capacity of pig somatic cell nuclear transfer embryos

Objective

To examine the effect of PCI-24781 (abexinostat) on the blastocyst formation rate in pig somatic cell nuclear transferred (SCNT) embryos and acetylation levels of the histone H3 lysine 9 and histone H4 lysine 12.

Results

Treatment with 0.5 nM PCI-24781 for 6 h significantly improved the development of cloned embryos, in comparison to the control group (25.3 vs. 10.5 %, P < 0.05). Furthermore, PCI-24781 treatment led to elevated acetylation of H3K9 and H4K12. TUNEL assay and Hoechst 33342 staining revealed that the percentage of apoptotic cells in blastocysts was significantly lower in PCI-24781-treated SCNT embryos than in untreated embryos. Also, PCI-24781-treated embryos were transferred into three surrogate sows, one of whom became pregnant and two fetuses developed.

Conclusion

PCI-24781 improves nuclear reprogramming and the developmental potential of pig SCNT embryos.

     

High-level expression and biochemical characterization of a novel cold-active lipase from <Emphasis Type="Italic">Rhizomucor endophyticus</Emphasis>

Objectives

To identify novel cold-active lipases from fungal sources and improve their production by heterologous expression in Pichia pastoris.

Results

A novel cold-active lipase gene (ReLipB) from Rhizomucor endophyticus was cloned. ReLipB was expressed at a high level in Pichia pastoris using high cell-density fermentation in a 5-l fermentor with the highest lipase activity of 1395 U/ml. The recombinant lipase (RelipB) was purified and biochemically characterized. ReLipB was most active at pH 7.5 and 25 °C. It was stable from pH 4.5–9.0. It exhibited broad substrate specificity towards p-nitrophenyl (pNP) esters (C₂–C₁₆) and triacylglycerols (C₂–C₁₂), showing the highest specific activities towards pNP laurate (231 U/mg) and tricaprylin (1840 U/mg), respectively. In addition, the enzyme displayed excellent stability with high concentrations of organic solvents including cyclohexane, n-hexane, n-heptane, isooctane and petroleum ester and surfactants.

Conclusions

A novel cold-active lipase from Rhizomucor endophyticus was identified, expressed at a high level and biochemically characterized. The high yield and unique enzymatic properties make this lipase of some potential for industrial applications.

     

Development of a sensitive molecular detection assay for mango malformation disease caused by <Emphasis Type="Italic">Fusarium mangiferae</Emphasis>

Objectives

To develop a sensitive and specific molecular assay for detection of mango malformation disease (MMD), which is caused primarily by Fusarium mangiferae.

Results

We screened 100 ISSR primers and identified one (UBC888) that directed the stable amplification of a specific gene fragment of 479 bp (GenBank accession number KJ526382). Based on the DNA sequence of this fragment, a pair of SCAR primers (W342 and W1772) were designed to amplify another gene fragment of 1376 bp (GenBank accession number KJ526383), demonstrating the successful conversion of an ISSR marker to a SCAR marker. An effective and simple detection assay for MMD was established based on this pair of PCR primers, with a high level of specificity and sensitivity to the DNA of F. mangiferae and other species of Fusarium both in vitro and in vivo. It can detect as little as 10 pg fungal DNA from the DNA of mango’s tissues.

Conclusions

Our assay provides a practical method for the early diagnosis so that proper prevention of the mango malformation disease can be developed.