Cytotoxic capacity of hepatitis C virus (HCV)--specific lymphocytes after in vitro immunization with HCV-derived lipopeptides.

BACKGROUND: Hepatitis C virus (HCV)-derived lipopeptides can induce epitope-specific immune responses in lymphocytes from HCV-naive individuals. We analyzed whether such T cells generated by in vitro immunization with HCV core-derived lipopeptides exert HCV-specific cytolytic activity. METHODS: Using a sensitive flow cytometric cytotoxicity assay we characterized HCV-specific cytotoxicity in T cells generated in vitro with HCV core-derived 25-mer lipopeptides. In addition, we studied expressions of Fas ligand and perforin and interferon-gamma (IFN-gamma) secretion in HLA-A2-HCV(core_35-44) tetramer-positive T cells generated with lipopeptide amino acid 20-44 (LP20-44). RESULTS: CD8+ T cells induced in vitro with HCV core-derived lipopeptides only infrequently exerted HCV-specific cytotoxicity, irrespective of whether antigen-coated T2 cells or autologous B lymphoblasts were used as targets. Detailed analysis of HLA-A2-HCV(core_35-44) tetramer-positive T cells generated with LP20-44 revealed that in vitro immunization resulted in T cells that secreted IFN-gamma after antigen-specific restimulation and that upregulated expression of Fas ligand but not of perforin. CONCLUSIONS: Our data confirm at the functional level that HCV lipopeptides induce antigen-specific T lymphocytes that produce IFN-gamma but exert significant cytotoxicity in only a minority of experiments, probably because expression of cytolytic effector molecules is not enhanced in their granules.     

Mating interference of glassy‐winged sharpshooters,Homalodisca vitripennis

Animal communication is a complex behavior that is influenced by abiotic and biotic factors of the environment. Glassy‐winged sharpshooters (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), primarily use vibrational signaling for courtship communication. Because GWSS is a major pest, transmitting the plant pathogenic bacterium Xylella fastidiosa Wells et al., interruption of communication is a possible avenue for control. Playback of white noise, pre‐recorded female signals, and artificial female noise (continuously overlapping female signals) significantly reduced mating of GWSS when compared to silent control mating trials. Furthermore, to begin to determine the mechanism underlying playback control, female signaling activity was recorded in the presence of stimuli. In response to playback of female signals, females signaled (duet‐like) more often than females tested in the absence of playback. After the first playback, almost two‐thirds of females signaled a response within 3 s. Additionally, one‐third of the females signaled within 1 s after cessation of white noise, and significantly more in the time periods following noise termination. Results highlight how GWSS responds to differing competitive disturbances in the environment and lays important ground work that possibly could be used to develop pesticide‐free control methods.     

Participant Profiling and Pattern of Crop-Foraging in Chacma Baboons (<Emphasis Type="Italic">Papio hamadryas ursinus</Emphasis>) in Zimbabwe: Why Does Investigating Age–Sex Classes Matter?

Transformation and loss of natural habitat to urbanization and agriculture provide new opportunities for primates to feed on anthropogenic food sources. Currently, mitigation strategies fail to target the individuals responsible for initiating and maintaining this behavior. As primates mainly forage on crops in groups, we investigate the crop-foraging behavior of a group of 40 chacma baboons in Zimbabwe from the perspective of collective movements, i.e., when a group of animals move together in the same direction, thus resulting in a change of location. We collected data on 110 crop-foraging events during 35 days in March–April 2014. We recorded baboon movement and behavior with a camcorder and obtained further information through video analysis. Most crop-foraging events involved less than 20% of the troop and lasted less than 3 min. Although crop-foraging parties were composed of all age–sex classes, adult females and particularly adult males initiated most crop-foraging events and made direct movements (without stopping on the road) more often than nonadult participants. Baboons made up to five successive attempts to crop forage in a single crop-foraging event. Neither the number of participants nor the success of the crop-foraging events increased over the successive attempts. Finally, crop-foraging events were more successful and more frequent in unguarded areas than in guarded areas. These results suggest that group members are highly synchronized and that crop-foraging is based on a collective decision such as classical foraging movements. In addition, the short duration of the crop-foraging events might prevent detection of baboons by farmers. The more frequent initiation of crop-foraging by adults compared to nonadults might be explained by greater energetic needs or a greater tendency of adults to take risks. These preliminary data can help inform long-term strategies for farmers to reduce crop losses to baboons, as guarding helps reduce damage but does not prevent it.     

Photoinduced electron-transfer in perylenediimide triphenylamine-based dendrimers: single photon timing and femtosecond transient absorption spectroscopy.

The excited state dynamics of two generations perylenediimide chromophores substituted in the bay area with dendritic branches bearing triphenylamine units as well as those of the respective reference compounds are investigated. Using single photon timing and multi-pulse femtosecond transient absorption experiments a direct proof of a reversible charge transfer occurring from the peripheral triphenylamine to the electron acceptor perylenediimide core is revealed. Femtosecond pump-dump-probe experiments provide evidence for the ground state dynamics by populating excited vibronic levels. It is found by the means of both techniques that the rotational isomerization of the dendritic branches occurs on a time scale that ranges up to 1 ns. This time scale of the isomerization depends on the size of the dendritic arms and is similar both in the ground and excited state.     

Genetic structure of a foundation species: scaling community phenotypes from the individual to the region

Understanding the local and regional patterns of species distributions has been a major goal of ecological and evolutionary research. The notion that these patterns can be understood through simple quantitative rules is attractive, but while numerous scaling laws exist (e.g., metabolic, fractals), we are aware of no studies that have placed individual traits and community structure together within a genetics based scaling framework. We document the potential for a genetic basis to the scaling of ecological communities, largely based upon our long-term studies of poplars (Populus spp.). The genetic structure and diversity of these foundation species affects riparian ecosystems and determines a much larger community of dependent organisms. Three examples illustrate these ideas. First, there is a strong genetic basis to phytochemistry and tree architecture (both above- and belowground), which can affect diverse organisms and ecosystem processes. Second, empirical studies in the wild show that the local patterns of genetics based community structure scale up to western North America. At multiple spatial scales the arthropod community phenotype is related to the genetic distance among plants that these arthropods depend upon for survival. Third, we suggest that the familiar species-area curve, in which species richness is a function of area, is also a function of genetic diversity. We find that arthropod species richness is closely correlated with the genetic marker diversity and trait variance suggesting a genetic component to these curves. Finally, we discuss how genetic variation can interact with environmental variation to affect community attributes across geographic scales along with conservation implications.     

From genes to ecosystems: a synthesis of the effects of plant genetic factors across levels of organization

Using two genetic approaches and seven different plant systems, we present findings from a meta-analysis examining the strength of the effects of plant genetic introgression and genotypic diversity across individual, community and ecosystem levels with the goal of synthesizing the patterns to date. We found that (i) the strength of plant genetic effects can be quite high; however, the overall strength of genetic effects on most response variables declined as the levels of organization increased. (ii) Plant genetic effects varied such that introgression had a greater impact on individual phenotypes than extended effects on arthropods or microbes/fungi. By contrast, the greatest effects of genotypic diversity were on arthropods. (iii) Plant genetic effects were greater on above-ground versus below-ground processes, but there was no difference between terrestrial and aquatic environments. (iv) The strength of the effects of intraspecific genotypic diversity tended to be weaker than interspecific genetic introgression. (v) Although genetic effects generally decline across levels of organization, in some cases they do not, suggesting that specific organisms and/or processes may respond more than others to underlying genetic variation. Because patterns in the overall impacts of introgression and genotypic diversity were generally consistent across diverse study systems and consistent with theoretical expectations, these results provide generality for understanding the extended consequences of plant genetic variation across levels of organization, with evolutionary implications.