The direct electron transfer between human cytoglobin (Cygb) and the electrode surface, which would allow manipulating the oxidation states of the heme iron in Cygb, was first observed by immobilizing Cygb on a nanoporous gold (NPG) electrode via a carboxy-terminated alkanethiol. The voltammetric performances of the wild type and mutated Cygb-immobilized NPG electrodes were evaluated in the absence or presence of potential substrates. The obtained results demonstrated that the usefulness of the proposed method in understanding the function of Cygb in molecular basis.
Salusin-β is an endogenous bioactive peptide that was identified in a human full-length enriched cDNA library using bioinformatics analyses. In our previous study, we found that synthetic salusin-β exhibits antibacterial activity against only Gram-positive microorganisms such as Staphylococcus aureus NBRC 12732. Salusin-β has an ability to depolarize the cytoplasmic membrane of this bacterium, and this phenomenon may be linked to the antibacterial activity of this peptide. A cell-penetrating peptide (CPP), human immunodeficiency virus (HIV)-1 transactivator of transcription (Tat) (49-57) is a short cationic peptide that can traverse cell membranes. In this report, synthetic peptide conjugates of salusin-β and HIV-1 Tat (49-57) showed potent antibacterial activities against both Gram-positive Staphylococcus aureus NBRC 12732 and Gram-negative Escherichia coli NBRC 12734. The synthetic peptides also depolarized the cytoplasmic membrane of Escherichia coli NBRC 12734 as well as Staphylococcus aureus NBRC 12732. These results suggested that HIV-1 Tat (49-57) is a protein transduction domain or CPP that changes the interaction mode between salusin-β and the cell membrane of Escherichia coli NBRC 12734. By binding to HIV-1 Tat (49-57), salusin-β showed a broad antibacterial spectrum regardless of whether the target was a Gram-positive or Gram-negative bacterium.
The side effects of kwao keur dietary supplements (obtained from the tuberous root of Pueraria mirifica) have recently been reported by the Ministry of Health, Labour and Welfare, Japan. To control the quality of kwao keur products, its ingredients need to be maintained by characteristic marker compounds, such as miroestrol, deoxymiroestrol, and kwakhurin (KWA). In this study, we described the facile synthesis of KWA, a marker compound of P. mirifica. Our revised synthetic method produced KWA with shorter steps and higher yield than the reported method. Furthermore, the absolute purity of KWA was determined by quantitative NMR analysis for standardization as a reagent, and its purity was 92.62 ± 0.12%.
A novel polymer (PEG2000-carborane), self-assembling into spherical vesicles (boron-containing vesicles, BCVs), could be quickly taken up by tumor cells and had an enhance stability in the bloodstream in previous study. To have more comprehensive understanding of BCVs, endocytic mechanism and cytotoxicity assessment were conducted. The results showed that BCVs were taken up in the intact form with cholesterol-dependent pathway during endocytosis, and BCVs exhibited nearly no cytotoxicity. BCVs could accumulate within tumors for at least 24 h. The data would provide reference information and guidance for BCVs’ multifunctional application serving as a boron delivery agent for BNCT, a hydrophilic and/or hydrophobic drug carrier and a diagnostic imaging fluorescent probe.
Facile and effective detection of dopamine (DA) plays a significant role in current clinical applications. Substantially, special optical nanomaterials are important for fabricating easy-to-control, cheap, selective, and portable fluorescence DA sensors with superior performance. Herein, carbon dots (CDs) prepared from melting method were applied as signal to establish a simple but effective fluorescence strategy for DA determination based on the enzymatic activity of acid phosphatase (ACP), which induces DA to form polydopamine (pDA). The formed pDA caused by the enzymatic oxidization of ACP toward DA can interact with CDs through the inner filter effect. Such behavior effectively quenched the CDs’ fluorescence. The degree of fluorescence quenching of CDs was positively correlated with the DA content. Under the optimized reaction conditions, the proposed fluorescence method exhibited a comparable analytical performance with other DA sensors with good selectivity. Furthermore, this method has been successfully applied to detect DA in DA hydrochloride injection and human serum samples. It shows that this method features potential practical application value and is expected to be used in clinical research.