The influence of temperature and precipitation on spring dispersal of Frankliniella fusca changes as the season progresses

Effects of temperature and precipitation on spring dispersal patterns of Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) caught on yellow sticky traps were estimated in central and eastern North Carolina and eastern Virginia, USA, from 1997 to 2001, and in 2004 and 2007. Data were collected from 44 sites within 14 locations over 7 years, resulting in 30 location‐year data combinations. The following independent variables were examined to determine their relationship to the number of F. fusca caught on sticky traps during specified time intervals: cumulative degree days (base 10.5 °C) from 1 November to the start of each trapping interval (DD), number of days with temperatures favorable for flight during each trapping interval (DTFF), and an index of rainfall during specific intervals prior to and during the trapping interval (RI). Regression models that contained various combinations of these variables explained 62, 79, 74, and 68% of the variation in the number of dispersing F. fusca captured during 1–15 April, 16–30 April, 1–15 May, and 16–31 May, respectively. The results provide strong evidence that the suppressive effects of precipitation on growth of local populations developing during late winter and early spring are subsequently manifest at the landscape scale as reductions in the populations of dispersing adults that may persist for as long as 5–6 weeks after the precipitation occurs.     

The CD8+ T cell population elicited by recombinant adenovirus displays a novel partially exhausted phenotype associated with prolonged antigen presentation that nonetheless provides long-term immunity

We have previously reported that the CD8+ T cell response elicited by recombinant adenovirus vaccination displayed a delayed contraction in the spleen. In our current study, we demonstrate that this unusual kinetic is a general phenomenon observed in multiple tissues. Phenotypic analysis of transgene-specific CD8+ T cells present 30 days postimmunization with recombinant adenovirus revealed a population with evidence of partial exhaustion, suggesting that the cells had been chronically exposed to Ag. Although Ag expression could no longer be detected 3 wk after immunization, examination of Ag presentation within the draining lymph nodes demonstrated that APCs were loaded with Ag peptide for at least 40 days postimmunization, suggesting that Ag remains available to the system for a prolonged period, although the exact source of this Ag remains to be determined. At 60 days postimmunization, the CD8+ T cell population continued to exhibit a phenotype consistent with partially exhausted effector memory cells. Nonetheless, these CD8+ T cells conferred sterilizing immunity against virus challenge 7-12 wk postimmunization, suggesting that robust protective immunity can be provided by CD8+ T cells with an exhausted phenotype. These data demonstrate that prolonged exposure to Ag may not necessarily impair protective immunity and prompt a re-evaluation of the impact of persistent exposure to Ag on T cell function.     

Spatial mutation of the T cell immunological synapse

The hardware for intracellular signaling networks consists of cascades of chemical reactions. It is becoming increasingly apparent that the large-scale spatial organization of molecules in these networks can lead to differential outcomes from otherwise chemically equivalent systems. This has amplified interest in controlled spatial organization as a regulator of cellular signal transduction. In response, a new category of experimentation is developing, in which the spatial positions of signaling molecules in living cells are directly manipulated through mechanical means. These methodologies complement conventional genetic and pharmacological approaches, both of which are chemical in nature, by perturbing the system through exclusively physical mechanisms.     

Useful applications of DOSY experiments for the study of mushroom polysaccharides

DOSY analysis has been performed on different mushroom extracts and fractions with the aim to describe a general method for the study of high molecular weight polysaccharides. These NMR experiments can be exploited to monitor the fractionation pathways performed on crude extracts in order to isolate polysaccharides. DOSY can also rapidly verify the purity of the isolated compounds, as well as evaluate their molecular size. In spite of the complexity of DOSY spectra of mixtures, this NMR technique seems to be a valid analytical tool that could be adopted as a routine method for the study of polysaccharides from different sources.     

Once phosphorylated, tyrosines in carboxyl terminus of protein-tyrosine kinase Syk interact with signaling proteins, including TULA-2, a negative regulator of mast cell degranulation

Activation of the high affinity IgE-binding receptor (FcεRI) results in the tyrosine phosphorylation of two conserved tyrosines located close to the COOH terminus of the protein-tyrosine kinase Syk. Synthetic peptides representing the last 10 amino acids of the tail of Syk with these two tyrosines either nonphosphorylated or phosphorylated were used to precipitate proteins from mast cell lysates. Proteins specifically precipitated by the phosphorylated peptide were identified by mass spectrometry. These included the adaptor proteins SLP-76, Nck-1, Grb2, and Grb2-related adaptor downstream of Shc (GADS) and the protein phosphatases SHIP-1 and TULA-2 (also known as UBASH3B or STS-1). The presence of these in the precipitates was further confirmed by immunoblotting. Using the peptides as probes in far Western blots showed direct binding of the phosphorylated peptide to Nck-1 and SHIP-1. Immunoprecipitations suggested that there were complexes of these proteins associated with Syk especially after receptor activation; in these complexes are Nck, SHIP-1, SLP-76, Grb2, and TULA-2 (UBASH3B or STS-1). The decreased expression of TULA-2 by treatment of mast cells with siRNA increased the FcεRI-induced tyrosine phosphorylation of the activation loop tyrosines of Syk and the phosphorylation of phospholipase C-γ2. There was parallel enhancement of the receptor-induced degranulation and activation of nuclear factor for T cells or nuclear factor κB, indicating that TULA-2, like SHIP-1, functions as a negative regulator of FcεRI signaling in mast cells. Therefore, once phosphorylated, the terminal tyrosines of Syk bind complexes of proteins that are positive and negative regulators of signaling in mast cells.     

EGFR signaling is required for regenerative proliferation in the cochlea: conservation in birds and mammals

Proliferation and transdifferentiaton of supporting cells in the damaged auditory organ of birds lead to robust regeneration of sensory hair cells. In contrast, regeneration of lost auditory hair cells does not occur in deafened mammals, resulting in permanent hearing loss. In spite of this failure of regeneration in mammals, we have previously shown that the perinatal mouse supporting cells harbor a latent potential for cell division. Here we show that in a subset of supporting cells marked by p75, EGFR signaling is required for proliferation, and this requirement is conserved between birds and mammals. Purified p75+ mouse supporting cells express receptors and ligands for the EGF signaling pathway, and their proliferation in culture can be blocked with the EGFR inhibitor AG1478. Similarly, in cultured chicken basilar papillae, supporting cell proliferation in response to hair cell ablation requires EGFR signaling. In addition, we show that EGFR signaling in p75+ mouse supporting cells is required for the down-regulation of the cell cycle inhibitor p27(Kip1) (CDKN1b) to enable cell cycle re-entry. Taken together, our data suggest that a conserved mechanism involving EGFR signaling governs proliferation of auditory supporting cells in birds and mammals and may represent a target for future hair cell regeneration strategies.     

Distribution and management of citrus in California: implications for management of glassy-winged sharpshooter

The epidemiology of Pierce's disease of grape (Vitis spp.) in California has changed over the past 10 yr due to the introduction of an exotic vector, Homalodisca vitripennis (Germar), the glassy-winged sharpshooter. Although this insect is highly polyphagous, citrus (Citrus spp.) is considered a preferred host and proximity to citrus has been implicated as a significant risk factor in recent epidemics of Pierce's disease in southern California. Consequently, a detailed knowledge of the distribution and management of citrus in relation to grape is needed to improve insect and disease management. Analysis of data on the area planted to these two commodities indicates that only five counties in California concomitantly grow >1,000 ha of grape and >1,000 ha of citrus: Riverside, Kern, Tulare, Fresno, and Madera counties. Comparison of the distribution of grape and citrus within each of these counties indicates that the percentage of grape that is in proximity to citrus is greatest for Riverside County, but the total area of grape that is in proximity to citrus is greater for Fresno, Kern, and Tulare counties. The use of carbamates, neonicotinoids, organophosphates, and pyrethroids as part of the citrus pest management program for control of key insect pests was compared among the same five counties plus Ventura County from 1995 to 2006. Ventura County was included in this analysis as this county grows >10,000 ha of citrus and has established glassy-winged sharpshooter populations. The use of these broad-spectrum insecticides was lowest in Riverside and Ventura counties compared with the other four counties. Analysis of historical trapping data at the county scale indicates a negative association of broad-spectrum insecticide use with glassy-winged sharpshooter abundance. These results are used to retrospectively analyze the Pierce's disease outbreaks in Kern and Riverside counties.