Texas Sour Orange Juice Used in Scaffolds for Tissue Engineering.

Fine fibers of polyhydroxybutyrate (PHB), a biopolymer, were developed via a centrifugal spinning technique. The developed fibers have an average diameter of 1.8 µm. Texas sour orange juice (SOJ) was applied as a natural antibacterial agent and infiltrated within the fibrous membranes. The antibacterial activity against common Gram-positive and Gram-negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) was evaluated as well as cell adhesion and viability. The PHB/SOJ scaffolds showed antibacterial activity of up to 152% and 71% against S. aureus and E. coli, respectively. The cell studies revealed a suitable environment for cell growth and cell attachment. The outcome of this study opens up new opportunities for fabrication of fibrous materials for biomedical applications having multifunctional properties while using natural agents.

Isolation and Characterization of the Lytic Cold-Active Bacteriophage MYSP06 from the Mingyong Glacier in China.

As unique ecological systems, glaciers are characterized by low temperatures and low nutrient levels, which allow them to be considered as "living fossils" for the purpose of researching the evolution of life and the environmental evolution of the earth. Glaciers are also natural microbial "reservoirs". In this work, a lytic cold-active bacteriophage designated MYSP06 was isolated from Janthinobacterium sp. MYB06 from the Mingyong Glacier in China, and its major characteristics were determined. Electron microscopy revealed that bacteriophage MYSP06 had an isometric head (74 nm) and a long tail (10 nm in width, 210 nm in length). It was classified as a Siphoviridae with an approximate genome size of 65­70 kb. A one-step growth curve revealed that the latent and burst periods were 95 and 65 min, respectively, with an average burst size of 16 bacteriophage particles per infected cell. The bacteriophage particles (100 %) adsorbed to the host cells within 10 min after infection. Moreover, the pH value and thermal stability of bacteriophage MYSP06 were also investigated. The maximum stability of the bacteriophage was observed at the optimal pH 7.0, and the bacteriophage became completely unstable at the extremely alkaline pH 11.0; however, it was comparatively stable at the acidic alkaline pH 6.0. As MYSP06 is a cold-active bacteriophage with a lower production temperature, its characterization and its relationship with its host Janthinobacterium sp. MYB06 deserve further study.

Development of tannic acid/chitosan/pullulan composite nanofibers from aqueous solution for potential applications as wound dressing.

This study presents the successful development of biocompatible tannic acid (TA)/chitosan (CS)/pullulan (PL) composite nanofibers (NFs) with synergistic antibacterial activity against the Gram-negative bacteria Escherichia coli. The NFs were developed utilizing the forcespinning(®) (FS) technique from CS-CA aqueous solutions to avoid the usage of toxic organic solvents. The ternary nanofibrous membranes were crosslinked to become water stable for potential applications as wound dressing. The morphology, structure, water solubility, water absorption capability and thermal properties of the NFs were characterized. The ternary composite membrane exhibits good water absorption ability with rapid uptake rate. This novel membrane favors fibroblast cell attachment and growth by providing a 3D environment which mimics the extracellular matrix (ECM) in skin and allows cells to move through the fibrous structure resulting in interlayer growth throughout the membrane, thus favoring potential for deep and intricate wound healing.

A serine/threonine phosphatase encoded by MG_207 of Mycoplasma genitalium is critical for its virulence.

BACKGROUND: Bacterial signal transduction systems like two component system (TCS) and Serine/Threonine kinase (STK) and Serine/Threonine phosphatase (STP) play important roles in the virulence and pathogenesis of bacterial pathogens. Mycoplasma genitalium, a mollicute that causes the urogenital diseases urethritis and cervicitis in men and women, respectively, is a pathogen which lacks TCS but possesses STK/STP. In this study, we investigated the biochemical and virulence properties of an STP protein encoded by the gene MG_207 of this species. RESULTS: We overexpressed MG207 in Escherichia coli overexpression system as a recombinant His10MG207 protein and purified it with affinity chromatography. This recombinant protein readily hydrolyzed the substrate p-nitrophenyl phosphate (pNPP) in a dose-dependent manner. Additional studies using synthetic peptides as substrates revealed that the recombinant protein was able to hydrolyze the threonine phosphate. Further, a transposon insertion mutant strain of M. genitalium (TIM207) that lacks the protein MG207 showed differentially phosphorylated proteins when compared to the wild type G37 strain. Mass spectrometry revealed that some of the key proteins differentially phosphorylated in TIM207 strain were putative cytoskeletal protein encoded by the gene MG_328 and pyruvate dehydrogenase E1 α chain encoded by the gene MG_274. In addition, TIM207 was noticed to be less cytotoxic to HeLa cells and this correlated with the production of less hydrogen peroxide by this strain. This strain was also less efficient in inducing the differentiation of THP-1 cell line as compared to wild type M. genitalium. CONCLUSIONS: The results of the study suggest that MG207 is an important signaling protein of M. genitalium and its presence may be crucial for the virulence of this species.