Hispidin induces autophagic and necrotic death in SGC-7901 gastric cancer cells through lysosomal membrane permeabilization by inhibiting tubulin polymerization.

Hispidin and its derivatives are widely distributed in edible mushrooms. Hispidin is more cytotoxic to A549, SCL-1, Bel7402 and Capan-1 cancer cells than to MRC5 normal cells; by contrast, hispidin protects H9c2 cardiomyoblast cells from hydrogen peroxide-induced or doxorubicin-induced apoptosis. Consequently, further research on how hispidin affects normal and cancer cells may help treat cancer and reduce chemotherapy-induced side effects.

Multiple transporters are involved in natamycin efflux in Streptomyces chattanoogensis L10.

Antibiotic-producing microorganisms have evolved several self-resistance mechanisms to prevent auto-toxicity. Overexpression of specific transporters to improve the efflux of toxic antibiotics has been found one of the most important and intrinsic resistance strategies used by many Streptomyces strains. In this work, two ATP-binding cassette (ABC) transporter-encoding genes located in the natamycin biosynthetic gene cluster, scnA and scnB, were identified as the primary exporter genes for natamycin efflux in Streptomyces chattanoogensis L10.

Improvement of natamycin production by engineering of phosphopantetheinyl transferases in Streptomyces chattanoogensis L10.

Phosphopantetheinyl transferases (PPTases) are essential to the activities of type I/II polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) through converting acyl carrier proteins (ACPs) in PKSs and peptidyl carrier proteins (PCPs) in NRPSs from inactive apo-forms into active holo-forms, leading to biosynthesis of polyketides and nonribosomal peptides. The industrial natamycin (NTM) producer, Streptomyces chattanoogensis L10, contains two PPTases (SchPPT and SchACPS) and five PKSs. Biochemical characterization of these two PPTases shows that SchPPT catalyzes the phosphopantetheinylation of ACPs in both type I PKSs and type II PKSs, SchACPS catalyzes the phosphopantetheinylation of ACPs in type II PKSs and fatty acid synthases (FASs), and the specificity of SchPPT is possibly controlled by its C terminus.

Involvement of SigT and RstA in the differentiation of Streptomyces coelicolor.

SigT is an ECF sigma factor in Streptomyces coelicolor. sigT and its putative anti-sigma factor gene rstA are located in one putative operon, and SigT could physically interact with RstA. Deletion of sigT or rstA caused accelerated morphological development and enhanced production of antibiotics, concomitant with over-expression of chpE, chpH, actII-orf4 and redD.

Reciprocal regulation between SigK and differentiation programs in Streptomyces coelicolor.

Here we reported that deletion of SigK (SCO6520), a sigma factor in Streptomyces coelicolor, caused an earlier switch from vegetative mycelia to aerial mycelia and higher expression of chpE and chpH than that in the wild type. Loss of SigK also resulted in accelerated and enhanced production of antibiotics, actinorhodin, and undecylprodigiosin and increased expression of actII-orf4 and redD. These results suggested that SigK had a negative role in morphological transition and secondary metabolism.

On the spontaneous encapsulation of proteins in carbon nanotubes.

Biomolecules-carbon nanotube (CNT) interactions are of great importance in CNT-based drug delivery systems and biomedical devices. In this study, a spontaneous encapsulation of a globular protein into the CNT was observed through molecular dynamics simulation. The free energy of the system was found to be decreased after the encapsulation, which is the most fundamental reason for this spontaneous process.

Dynamic mechanism of collagen-like peptide encapsulated into carbon nanotubes.

Carbon nanotubes (CNTs)-based devices and their applications have received more and more attention, and several biomolecules have been found to be encapsulated into the inner space of the CNTs spontaneously. In this work, the molecular dynamics simulations demonstrate that a collagen-like peptide with a hydrophobic center and hydrophilic surfaces could be inserted into CNTs spontaneously but slowly. Then the dynamic mechanism of the encapsulation process was investigated by a series of steered molecular dynamics simulations.

FtsY affects sporulation and antibiotic production by whiH in Streptomyces coelicolor.

FtsY, the Signal Recognition Particle (SRP) receptor in bacteria, is known to facilitate the cotranslational protein targeting by recruiting SRP-protein complex to secYEG. We show in this work that deletion of the ftsY gene in Streptomyces coelicolor would also lead to complete blockage of sporulation process and reduced production of antibiotic actinorhodin. These defects cannot be complemented by only the NG domain of FtsY, while full-length ftsY was able to restore spore generation and increase production of actinorhodin in ftsY-disrupted strains.

Analysis of the GTPase activity and active sites of the NG domains of FtsY and Ffh from Streptomyces coelicolor.

Fifty-four homolog (Ffh) and FtsY are the central components of the signal recognition particle secretory pathway of bacteria. In this study, the core domain and active sites of FtsY and Ffh from Streptomyces coelicolor, which are responsible for guanosine triphosphate (GTP) hydrolysis, were identified using site-directed mutagenesis. Mutations were introduced to the conserved GXXGXGK loop of the putative GTP binding site.

Whole genome analysis of non-optimal codon usage in secretory signal sequences of Streptomyces coelicolor.

Non-optimal (rare) codons have been suggested to reduce translation rate and facilitate secretion in Escherichia coli. In this study, the complete genome analysis of non-optimal codon usage in secretory signal sequences and non-secretory sequences of Streptomyces coelicolor was performed. The result showed that there was a higher proportion of non-optimal codons in secretory signal sequences than in non-secretory sequences.

[Research progress of targeting and translocation of proteins mediated by signal recognition particle in prokaryote].

How proteins are targeted and translocated mediated by signal recognition particle (SRP) in eukaryotic cell is very clear and uniform. In contrast, SRP systems are different in various kinds of prokaryotic cells, So it is difficult to identify. Nowadays, the studies of prokaryotic SRP system focus on the structure and function of Ffh, FtsY, 4.

[Design of portable biomedical information detecting instruments].

The article discusses how to design a portable instrument to detect the biomedical information in five aspects, such as signal catching, MPU selecting, anti-interference, power controlling and portability. It gives some ideas to solve the problems in instrument designing.

Glucose biosensor based on multi-wall carbon nanotubes and screen printed carbon electrodes.

This paper describes a disposable electrochemical biosensor for glucose monitoring. The sensor was based on multi-wall carbon nanotubes (MWCNTs) immobilized with glucose oxidase and upon screen printed carbon electrode. The effect of MWCNTs on the response of amperometric glucose oxidase electrode for glucose was examined.

Constitutive expression of human angiostatin in Pichia pastoris using the GAP promoter.

The GAP gene promoter was amplified from P. pastoris GS115 and used to replace the AOX1 promoter (P(AOX1)) on pPIC9K resulting in plasmid pGAP9K. The recombinant expression vector pGAP9K-AS was constructed by inserting the angiostatin gene(AS) into pGAP9K.