Over the past decade, peptides have emerged as a new family of potential carriers in gene therapy. Peptides are easy to synthesize and quite stable. Additionally, sequences shared by the host proteome are not expected to be immunogenic or trigger inflammatory responses, which are commonly observed with viral approaches. We recently reported on a new class of branched amphiphilic peptide capsules (BAPCs) that self-assemble into extremely stable nanospheres. These capsules are capable of retaining and delivering alpha-emitting radionuclides to cells. Here we report that, in the presence of double stranded plasmid DNA, BAPCs are unable to form. Instead, depending of the peptide/DNA ratios, the peptides either coat the plasmid surface forming nanofibers (high peptide to DNA ratio) or condense the plasmid into nanometer-sized compacted structures (at low peptide to DNA ratios). Different gene delivery efficiencies are observed for the two types of assemblies. The compacted nanometer-sized structures display much higher transfection efficiencies in HeLa cells. This level of transfection is greater than that observed for a lipid-based reagent when the total number of viable transfected cells is taken into account.

The peptidergic signaling system is an ancient cell-cell communication mechanism that is involved in numerous behavioral and physiological events in multicellular organisms. We identified two novel neuropeptides in the neuronal projections innervating the salivary glands of the blacklegged tick, Ixodes scapularis (Say, 1821). Myoinhibitory peptide (MIP) and SIFamide immunoreactivities were colocalized in the protocerebral cells and their projections terminating on specific cells of salivary gland acini (types II and III). Immunoreactive substances were identified by matrix-assisted laser desorption/ionization-time of flight (MALDITOF) analysis: a 1,321.6-Da peptide with the sequence typical for MIP (ASDWNRLSGMWamide) and a 1,395.7-Da SIFamide (AYRKPPFNGSIFamide), which are highly conserved among arthropods. Genes encoding these peptides were identified in the available Ixodes genome and expressed sequence tag (EST) database. In addition, the cDNA encoding the MIP prepropeptide was isolated by rapid amplification of cDNA ends (RACE). In this report, we describe the anatomical structure of specific central neurons innervating salivary gland acini and identify different neuropeptides and their precursors expressed by these neurons. Our data provide evidence for neural control of salivary gland by MIP and SIFamide from the synganglion, thus leading a basis for functional studies of these two distinct classes of neuropeptides. Keywords neuropeptide; myoinhibitory peptide; MIP; SIFamide; MALDI; synganglion; salivary glands Ticks are obligatory external parasites that feed on the blood of mammals, birds, and reptiles and often transmit pathogenic viruses, Rickettsiae, bacteria, and protozoa. Tick-borne diseases cause substantial economic loss in the animal industry and present risks for human health. The black-legged tick, Ixodes scapularis, transmits the most important tick-borne pathogen, Borrelia burgdorferi, which causes Lyme disease. More than 20,000 new cases are reported per year in the United States, in 46 states. This species also transmits other diseases, including human babesiosis Babesia microti and human granulocytic ehrlichiosis.Salivary secretions of ticks are essential during feeding for manipulation and suppression of host defense responses and might represent key components in the transmission of (Binnington, 1978;Coons and Roshdy, 1973;Krolak et al., 1982). Each type of acinus contains multiple cell types, including different types of secretory and epithelial cells (Balashov et al., 1983;Sauer et al., 1995;Sonenshine, 1993). Studies with transmission electron microscopy have discovered that axon terminals reach the basal region of the acini, indicating that there is neuronal control of the salivary glands (Balashov et al., 1983; Coons and Alberti, 1999). Recently, we have described the neuroanatomy of peptidergic cells in the nervous system, including the neurons and axonal projections that innervate tick salivary glands (Šimo et al., 2009).Previous immunohistochemical studies have indica...