Short communication: bovine-derived proteins activate STAT3 in human skeletal muscle in vitro

Bovine milk contains biologically active peptides that may modulate growth and development within humans. In this study, targeted bovine-derived proteins were evaluated for their effects on signal transducer and activator of transcription-3 (STAT3) phosphorylation in human skeletal muscle cells. Following an acute exposure, bovine-derived acidic fibroblast growth factor-1 (FGF) and leukemia inhibitory factor (LIF) activated STAT3 in differentiating myotubes. Chronic exposure to FGF and LIF during the proliferative phase reduced myoblast proliferation and elevated MyoD and creatine kinase (CKM) mRNA expression without altering apoptotic genes. In mature myotubes, neither FGF nor LIF elicited any action. Together, these data indicate that a reduction in proliferation in the presence of bovine-derived FGF or LIF may stimulate early maturation of myoblasts.

Signaling via the CytoR/JAK/STAT/SOCS pathway: emergence during evolution

Cell-cell signaling represents an essential hallmark of multicellular organisms, which necessarily require a means of communicating between different cell populations, particularly immune cells. Cytokine receptor signaling through the Janus kinase/Signal Transducer and Activator of Transcription/Suppressor of Cytokine Signaling (CytoR/JAK/STAT/SOCS) pathway embodies one important paradigm by which this is achieved. This pathway has been extensively studied in vertebrates and protostomes and shown to play fundamental roles in development and function of immune and other cells. However, our understanding of the origins of the individual pathway components and their assembly into a functional pathway has remained limited. This study examined the origins of each component of this pathway through bioinformatics analysis of key extant species. This has revealed step-wise accretion of individual components over a large evolutionary time-frame, but only in bilateria did a series of innovations allow their final coalescence to form a complete pathway. Assembly of the CytoR/JAK/STAT pathway has followed the retrograde model of pathway evolution, whereas addition of the SOCS component has adhered to the patchwork model.

A Pb2+-ion electrochemical biosensor based on single-stranded DNAzyme catalytic beacon

A novel strategy for selective and sensitive electrochemical lead ion (Pb²⁺) biosensor was developed based on the single-stranded DNAzyme catalytic beacon. A DNAzyme that requires Pb²⁺ for activation was selected and labeled with redox-active ferrocene (Fc) for signal transducer. The Fc-labeled single-stranded DNAzyme (Fc-ssDNAzyme) was self-assembled through SAu bonding on a gold electrode surface. In the presence of Pb²⁺, the ssDNAzyme was activated and catalyzed the hydrolytic cleavage of the substrate strand, resulting in the removal of the substrate strand along with the Fc from the Au electrode surface. The dissociation of Fc caused a decrease of electrochemical signal ("signal-off"). Under the optimal conditions, the electrochemical signal of Fc decreased directly with the increasing Pb²⁺ concentration, exhibiting a linear response in the range of 0.5nM to 5μM with a detection limit of 0.25nM. This strategy is simple, sensitive and selective with the minimal reagents and working steps, thereby holds great potential for Pb²⁺ detection in real environmental sample analysis.