Psycholinguistic norms for more than 300 lexical manual signs in German Sign Language (DGS)

Sign languages provide researchers with an opportunity to ask empirical questions about the human language faculty that go beyond considerations specific to speech and writing. Whereas psycholinguists working with spoken and written language stimuli routinely control their materials for parameters such as lexical frequency and age of acquisition (AoA), no such information or normed stimulus sets are currently available to researchers working with German Sign Language (DGS). Our contribution presents the first norms for iconicity, familiarity, AoA, and transparency for DGS. The normed stimulus set consists of more than 300 clips of manual DGS signs accom- panied by mouthings and non-manual components. Norms for the signs in the clips are derived from ratings by a total of 30 deaf signers in Leipzig, Göttingen, and Hamburg, as well as 30 hearing non-signers and native speakers of German in Leipzig. The rating procedure was implemented in a browser to ensure functionality and a similar procedure across locations and participants (Figure 1a), yet all participants performed the ratings on site in the presence of an experimenter. Deaf signers performed a total of three tasks in which they rated stimulus clips for iconicity, AoA, and familiarity. Such subjective measures of AoA and familiarity have been shown to be good proxies for corpus measures in studies of other spoken and sign languages (Vinson, Cormier, Denmark, Schembri, & Vigliocco, 2008). Hearing non-signers performed two tasks in which they first guessed the meaning of the signs in the clips to determine transparency and in the second task rated iconicity given the meaning. In addition to empirical norming data (e.g., Figure 1b), we provide information about German and English correspondences of signs. The stimulus set has been annotated in machine-readable form with regard to lexico-semantic as well as phonological properties of signs: one-handed vs. two-handed, place of articulation, path movement, symmetry, most likely lexical class, animacy, verb type, (potential) homonymy, and potential dialectal variation. Information about sign on- and offset for all stimulus clips and a number of quantitative measures of movement are also available. These were derived from automated motion tracking by fitting a pose-estimation model (Figure 1c) to the clips using OpenPose (Wei, Ramakrishna, Kanade, & Sheikh, 2016) which allows us to quantify and automatically track movement (velocity and acceleration) beyond annotation (Figure 1d). In this presentation, we will focus on providing an overview of the derived norms and attempt to put them in perspective of published empirical norms for other sign languages, for example, ASL and BSL (Vinson et al., 2008; Caselli, Sehyr, Cohen-Goldberg, & Emmorey, 2017), as well as comparable information for spoken languages. This includes a comparison of our subjective rating data with regard to frequency and AoA obtained using DGS signs with norms for other sign languages as well as with similar measures for German and English. We also discuss the relationship of mean iconicity ratings between deaf signers and hearing non-signers, as well as the relation of iconicity and transparency. Our norms and stimulus set are intended to control for psychologically relevant param- eters in future psycho- and neurolinguistic studies of DGS beyond the work of our own labs. Consequently, the norms, stimulus clips, cleaned raw data, and the R scripts used for analysis will be made available for download through the Open Science Framework. References Caselli, N. K., Sehyr, Z. S., Cohen-Goldberg, A. M., & Emmorey, K. (2017). ASL-LEX: A lexical database of American Sign Language. Behavior Research Methods, 49(2), 784-801. doi: 10.3758/ s13428-016-0742-0 Vinson, D. P., Cormier, K., Denmark, T., Schembri, A., & Vigliocco, G. (2008). The British Sign Language (BSL) norms for age of acquisition, familiarity, and iconicity. Behavior Research Methods, 40(4), 1079-1087. doi: 10.3758/BRM.40.4.1079 Wei, S.-E., Ramakrishna, V., Kanade, T., & Sheikh, Y. (2016). Convolutional pose machines. arXiv:1602.00134 [cs]

Cloning and characterization of a trypsin-encoding cDNA of the human body louse Pediculus humanus

Abstract From a cDNA library of the whole insect, a trypsin gene of Pediculus humanus has been cloned and sequenced. The 908 bp clone has an open reading frame of 759 bp, which encodes a pre-proenzyme with 253 amino acid residues. A sixteen-residue N-terminal signal peptide is followed by a twelve-residue activation peptide with putative cleavage sites at Gly16 and Tyr28. The deduced amino acid sequence has several features typical of trypsin proteases and an overall identity of 35 -43% with the trypsins of several haematophagous Diptera. The 1.0 kb genomic trypsin gene contains three introns of 102, 79 and 80 nucleotides following the codons for Gly16, Gln74 and Ala155, respectively. Only a single gene seems to be present. In Northern blot analysis, unfed first instar larvae have an identical or slightly lower level of trypsin mRNA than fed adult lice, and in adults 2-24 h after the bloodmeal this gene shows a constitutive expression. After in vitro transcription and translation, the activation peptide is cleaved by chymotrypsin, a so far unreported phenomenon in trypsin activation

Actions of a Proline Analogue, L-Thiazolidine-4-Carboxylic Acid (T4C), on Trypanosoma cruzi

It is well established that L-proline has several roles in the biology of trypanosomatids. In Trypanosoma cruzi, the etiological agent of Chagas' disease, this amino acid is involved in energy metabolism, differentiation processes and resistance to osmotic stress. In this study, we analyzed the effects of interfering with L-proline metabolism on the viability and on other aspects of the T. cruzi life cycle using the proline analogue L- thiazolidine-4-carboxylic acid (T4C). The growth of epimastigotes was evaluated using different concentrations of T4C in standard culture conditions and at high temperature or acidic pH. We also evaluated possible interactions of this analogue with stress conditions such as those produced by nutrient starvation and oxidative stress. T4C showed a dose-response effect on epimastigote growth (IC50 = 0.89±0.02 mM at 28°C), and the inhibitory effect of this analogue was synergistic (p<0.05) with temperature (0.54±0.01 mM at 37°C). T4C significantly diminished parasite survival (p<0.05) in combination with nutrient starvation and oxidative stress conditions. Pre-incubation of the parasites with L-proline resulted in a protective effect against oxidative stress, but this was not seen in the presence of the drug. Finally, the trypomastigote bursting from infected mammalian cells was evaluated and found to be inhibited by up to 56% when cells were treated with non-toxic concentrations of T4C (between 1 and 10 mM). All these data together suggest that T4C could be an interesting therapeutic drug if combined with others that affect, for example, oxidative stress. The data also support the participation of proline metabolism in the resistance to oxidative stress

Nucleolar Accumulation of RNA Binding Proteins Induced by ActinomycinD Is Functional in Trypanosoma cruzi and Leishmania mexicana but Not in T. brucei

We have recently shown in T. cruzi that a group of RNA Binding Proteins (RBPs), involved in mRNA metabolism, are accumulated into the nucleolus in response to Actinomycin D (ActD) treatment. In this work, we have extended our analysis to other members of the trypanosomatid lineage. In agreement with our previous study, the mechanism seems to be conserved in L. mexicana, since both endogenous RBPs and a transgenic RBP were relocalized to the nucleolus in parasites exposed to ActD. In contrast, in T. brucei, neither endogenous RBPs (TbRRM1 and TbPABP2) nor a transgenic RBP from T. cruzi were accumulated into the nucleolus under such treatment. Interestingly, when a transgenic TbRRM1was expressed in T. cruzi and the parasites exposed to ActD, TbRRM1 relocated to the nucleolus, suggesting that it contains the necessary sequence elements to be targeted to the nucleolus. Together, both experiments demonstrate that the mechanism behind nucleolar localization of RBPs, which is present in T. cruzi and L. mexicana, is not functional in T. brucei, suggesting that it has been lost or retained differentially during the evolution of the trypanosomatid lineage

SUMOylation of Paraflagellar Rod Protein, PFR1, and Its Stage-Specific Localization in Trypanosoma cruzi

BACKGROUND: The flagellate protozoan parasite, Trypanosoma cruzi, is a causative agent of Chagas disease that is transmitted by reduviid bugs to humans. The parasite exists in multiple morphological forms in both vector and host, and cell differentiation in T. cruzi is tightly associated with stage-specific protein synthesis and degradation. However, the specific molecular mechanisms responsible for this coordinated cell differentiation are unclear. METHODOLOGY/PRINCIPAL FINDINGS: The SUMO conjugation system plays an important role in specific protein expression. In T. cruzi, a subset of SUMOlylated protein candidates and the nuclear localization of SUMO have been shown. Here, we examined the biological roles of SUMO in T. cruzi. Site-directed mutagenesis analysis of SUMO consensus motifs within T. cruzi SUMO using a bacterial SUMOylation system revealed that T. cruzi SUMO can polymerize. Indirect fluorescence analysis using T. cruzi SUMO-specific antibody showed the extra-nuclear localization of SUMO on the flagellum of epimastigote and metacyclic and bloodstream trypomastigote stages. In the short-flagellate intracellular amastigote, an extra-nuclear distribution of SUMO is associated with basement of the flagellum and becomes distributed along the flagellum as amastigote transforms into trypomastigote. We examined the flagellar target protein of SUMO and show that a paraflagellar rod protein, PFR1, is SUMOylated. CONCLUSIONS: These findings indicate that SUMOylation is associated with flagellar homeostasis throughout the parasite life cycle, which may play an important role in differentiation of T. cruzi

Trypanosoma cruzi Immune Response Modulation Decreases Microbiota in Rhodnius prolixus Gut and Is Crucial for Parasite Survival and Development

Trypanosoma cruzi in order to complete its development in the digestive tract of Rhodnius prolixus needs to overcome the immune reactions and microbiota trypanolytic activity of the gut. We demonstrate that in R. prolixus following infection with epimastigotes of Trypanosoma cruzi clone Dm28c and, in comparison with uninfected control insects, the midgut contained (i) fewer bacteria, (ii) higher parasite numbers, and (iii) reduced nitrite and nitrate production and increased phenoloxidase and antibacterial activities. In addition, in insects pre-treated with antibiotic and then infected with Dm28c, there were also reduced bacteria numbers and a higher parasite load compared with insects solely infected with parasites. Furthermore, and in contrast to insects infected with Dm28c, infection with T. cruzi Y strain resulted in a slight decreased numbers of gut bacteria but not sufficient to mediate a successful parasite infection. We conclude that infection of R. prolixus with the T. cruzi Dm28c clone modifies the host gut immune responses to decrease the microbiota population and these changes are crucial for the parasite development in the insect gut