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The role of mammalian skin in harbouring and transmitting arthropod-borne protozoan parasites has been overlooked for decades as these pathogens have been regarded primarily as blood-dwelling organisms. Intriguingly, infections with low or undetected blood parasites are common, particularly in the case of Human African Trypanosomiasis caused by Trypanosoma brucei gambiense. We hypothesise, therefore, the skin represents an anatomic reservoir of infection. Here we definitively show that substantial quantities of trypanosomes exist within the skin following experimental infection, which can be transmitted to the tsetse vector, even in the absence of detectable parasitaemia. Importantly, we demonstrate the presence of extravascular parasites in human skin biopsies from undiagnosed individuals. The identification of this novel reservoir requires a re-evaluation of current diagnostic methods and control policies. More broadly, our results indicate that transmission is a key evolutionary force driving parasite extravasation that could further result in tissue invasion-dependent pathology. DOI: http://dx.doi.org/10.7554/eLife.17716.001

Ovodefensins are a novel beta defensin-related family of antimicrobial peptides containing conserved glycine and six cysteine residues. Originally thought to be restricted to the albumen-producing region of the avian oviduct, expression was found in chicken, turkey, duck, and zebra finch in large quantities in many parts of the oviduct, but this varied between species and between gene forms in the same species. Using new search strategies, the ovodefensin family now has 35 members, including reptiles, but no representatives outside birds and reptiles have been found. Analysis of their evolution shows that ovodefensins divide into six groups based on the intra-cysteine amino acid spacing, representing a unique mechanism alongside traditional evolution of sequence. The groups have been used to base a nomenclature for the family. Antimicrobial activity for three ovodefensins from chicken and duck was confirmed against Escherichia coli and a pathogenic E. coli strain as well as a Gram-positive organism, Staphylococcus aureus, for the first time. However, activity varied greatly between peptides, with Gallus gallus OvoDA1 being the most potent, suggesting a link with the different structures. Expression of Gallus gallus OvoDA1 (gallin) in the oviduct was increased by estrogen and progesterone and in the reproductive state. Overall, the results support the hypothesis that ovodefensins evolved to protect the egg, but they are not necessarily restricted to the egg white. Therefore, divergent motif structure and sequence present an interesting area of research for antimicrobial peptide design and understanding protection of the cleidoic egg.

Ovodefensins are a novel beta defensin-related family of antimicrobial peptides containing conserved glycine and six cysteine residues. Originally thought to be restricted to the albumen-producing region of the avian oviduct, expression was found in chicken, turkey, duck, and zebra finch in large quantities in many parts of the oviduct, but this varied between species and between gene forms in the same species. Using new search strategies, the ovodefensin family now has 35 members, including reptiles, but no representatives outside birds and reptiles have been found. Analysis of their evolution shows that ovodefensins divide into six groups based on the intra-cysteine amino acid spacing, representing a unique mechanism alongside traditional evolution of sequence. The groups have been used to base a nomenclature for the family. Antimicrobial activity for three ovodefensins from chicken and duck was confirmed against Escherichia coli and a pathogenic E. coli strain as well as a Gram-positive organism, Staphylococcus aureus, for the first time. However, activity varied greatly between peptides, with Gallus gallus OvoDA1 being the most potent, suggesting a link with the different structures. Expression of Gallus gallus OvoDA1 (gallin) in the oviduct was increased by estrogen and progesterone and in the reproductive state. Overall, the results support the hypothesis that ovodefensins evolved to protect the egg, but they are not necessarily restricted to the egg white. Therefore, divergent motif structure and sequence present an interesting area of research for antimicrobial peptide design and understanding protection of the cleidoic egg.

The possibility of using genes as medicines to treat brain diseases is currently limited by the lack of safe and efficacious delivery systems able to cross the blood-brain barrier, thus resulting in a failure to reach the brain after intravenous administration. On the basis that iron can effectively reach the brain by using transferrin receptors for crossing the blood-brain barrier, we propose to investigate if a transferrin-bearing generation 3-polypropylenimine dendrimer would allow the transport of plasmid DNA to the brain after intravenous administration. In vitro, the conjugation of transferrin to the polypropylenimine dendrimer increased the DNA uptake by bEnd.3 murine brain endothelioma cells overexpressing transferrin receptors, by about 1.4-fold and 2.3-fold compared to that observed with the non-targeted dendriplex and naked DNA. This DNA uptake appeared to be optimal following 2h incubation with the treatment. In vivo, the intravenous injection of transferrin-bearing dendriplex more than doubled the gene expression in the brain compared to the unmodified dendriplex, while decreasing the non-specific gene expression in the lung. Gene expression was at least 3-fold higher in the brain than in any tested peripheral organs and was at its highest 24h following the injection of the treatments. These results suggest that transferrin-bearing polypropylenimine dendrimer is a highly promising gene delivery system to the brain.

Astrophysical sources of very high energy neutrinos may offer a novel means of imaging the Earth's internal structure. Likewise, occultation by our planet's core-mantle structure can help constrain the locations of extragalactic neutrino sources. Neutrino observations from the Earth's surface thus motivate new levels of collaboration between astrophysics and geophysics.

Interactions of 1.61-Bev/c antiprotons in hydrogen yielding two charged particles have been studied, with particular attention to elastic scattering, single-pion production, and annihilation into three or more pions. Effects of misinterpretation of events are estimated by Monte Carlo calculations. Nine partial cross sections have been measured. The elastic-scattering data show a secondary diffraction peak at about 82 deg in the center-of-mass system. Single pion production is found to be consistent with charge-conjugation invariance. In the single pion events (p + p yields N + N + pi ) the predominance of low- momentum transfer exceeds that predicted by the single pion exchange formula of Chew and Low. No two-pion resonances have been observed anywhere in the data. (auth)

In the course ot studying a large number of decays of hyperons, produced in a hydrogen bubble chamber by 1.23 Bev/c pious, an uanambiguous case or a LAMBDA undergotng beta decay was found. Tbe events at the various vertices in the photograph are analyzed. (W.D.M.)

Deviations from the expected two-pion effective-mass distributions have been found in the reaction $\overline{p}+p\ensuremath{\rightarrow}2{\ensuremath{\pi}}^{+}+2{\ensuremath{\pi}}^{\ensuremath{-}}+n{\ensuremath{\pi}}^{0}$. These occur in two regions, 300 Mev and 750 Mev, and could be explained by the $T=0$, pion-pion interaction reported by Abashian, Booth, and Crowe and the widely observed $\ensuremath{\rho}$ meson ($T=1$, $J={1}^{\ensuremath{-}}$ pion-pion resonance). The data in the 750-Mev region for ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ combinations ($Q=0$) show an apparent double-peak structure---one at 720 Mev ($\ensuremath{\Gamma}=20$ Mev), the other at 780 Mev ($\ensuremath{\Gamma}=60$ Mev). However, the $|Q|=1$ data (${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ combinations) are consistent with the previously observed single $T=1$, $J={1}^{\ensuremath{-}}$ resonance. Our data give ${M}_{\ensuremath{\rho}}=767$ Mev ($\ensuremath{\Gamma}=110$ Mev). As these parameters also fit the $Q=0$ data, a detailed discussion of the statistical significance of the one-peak and two-peak hypotheses is given. A search has been made for possible neutral modes of decay of the heavy mesons, and no evidence has been found.

Author(s): Crawford, Frank S.; Cresti, Marcello; Good, Myron L.; Gottstein, Klaus.; Lyman, Ernest M.; Solmitz, Frank T.; Stevenson, M. Lynn; Ticho, Harold.

Author(s): Crawford, Frank S.; Cresti, Marcello; Good, Myron L.; Solmitz, Frank T.; Stevenson, M.Lynn.

Author(s): Berge, J. Peter; Eberhard, Philippe; Hubbard, J. Richard; Merrill, Deane W.; Shafer, Janice B.; Solmitz, Prank T.; Stevenson, M. Lynn.

Six cases of DELTA hyperons interacting with protons in a liquid hydrogen bubble chamber were found. The classes of DELTA interactions were DELTA + p yields DELTA + p (4 events) and DELTA + p yields SIGMA /sup +/ + n (2 events). No examples of the DELTA + p yields delta /sup 0/ + p reaction were found. The cross sections are computed for the reactions and for the inverse reactions. (W.D.M.)

The method recently proposed by Lee and Yang for determining the spin of the LAMBDA hyperon is applied to 614 decays of the type LAMBDA yields pi - + p. The A's were produced in a 10-inch liquid hydrogen bubble chamber via the reaction pi - + p yields K/ deg + LAMBDA . The method makes possible an absolute determination of the A spin without assumptions other than that angular momentum is conserved in the decay. It is concluded that the LAMBDA spin is 1/ 2. (W.D. M.)

The charge symmetry of K/sup +/ and K/sup 0/ mesons was tested by comparing e (as Fe/sup 59 /sup +/ and e (as Fe/sup 59 /sup -/ interactions at 1.23 Bev/c in the 72-in. deuterium bubble chamber. About 350 events of the type e (as Fe/sup 59 /sup +/ + d and up to st r K/sup +/ + in each case). (or / occurred in pu /sup 0/) + p and appeevents of the type e (as Fe/sup 59 /sup -/ + d and up to st r K/sup 0/ + in each case). (or /occurred in pu /sup 0ppared. Total cross sections, angular distributions, momentum spectra, and lambda decay asymmetries show no deviations from charge symmetry. Details on anglemomentum distributions and decay asymmetries are given. (auth)

Proton-antiproton annihilations at 1.61 13ev/c with only two mesons in the final state have been examined in the 72-in. bubble chamber. The partial cross sections measured are: p + p yields pi /sup -/ + pi /sup +/, 119 plus or minus 30 mu b; p + p yields K/sup -/ + K/sup +/, 55 plus or minus 18 mu b. The K/sup -/ distribution in p + p yields K/sup -/ + K/sup +/ is peaked strongly forward, with 7 of the 11 k/sup -/ mesons produced in the forwardmost tenth of the total solid angle. The pi /sup -/ events show no such effect, with only 2 of the 22 pi /sup -/ mesons being produced in the same forward interval. Careful study of possible contamination of these events indicates that almost all of them are genuine two-meson annihilations. (auth)

UNIVERSITY OF CALIFORNIA IWO-WEEK W A N COPY This i s (7 Librarg Crrcirlatir~~j Copy which mmj t ~ e borrowed for two weeks. For 61 personal retention copy, call Tech. Info. Diuision, Ext. 5545 BERKELEY, C A L I F O R N I A

The absolute differential cross sections were measured for the reactions pi /sup -/ + p yields SIGMA /sup 0/ + K/sup 0/ and pi /sup -/ + p yields SIGMA /sup -/ + K/sup +/, using 1.09 plus or minus 0.01 Bev negative pions incident on a 10-in. liquid hydrogen bubble chamber, with an 11-kilogauss magnetic field. Results are compared to those of Brown et al. (Phys. Rev. 107, 908(1957)) both as to magnitude and as to angular dependences. (W.D.M.)

Information is reported on the analysis of 185 events of the type pi - + p -- LAMBDA /sup o/ +K/sup o and LAMBDA /sup o/ > p+ pi /sup -, produced by pions of 1.23 bev/c, leading to 375 Mev/c LAMBDA 's in the c.m. system. (J.H.M.)