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Additive manufacturing (AM), generally also referred to as 3D printing, has gone through vast development in the past 20 years which still continues. In particular, the market segment of personal 3D printers has achieved an average annually growth rate of approximately 170% from 2008 to 2013. The purpose of this research is to identify the best AM process applied in personal printers in terms of cost, sustainability, surface roughness, and human perception, as these aspects are essential for this new thriving market segment's future. In addition, the research investigates which objective roughness parameters are suitable for qualifying subjective perceptions. The primary AM processes, Fused Deposition Modeling, Stereolithography and Polyjet printing are in the focus of this research. Manufacturing costs as well as environmental impact are calculated, five independent roughness parameters (Ra, Rz, Rq, Rsk, and Rku) are measured and the subjective perception of samples is assessed through sensorial analysis. In conclusion, samples manufactured with Polyjet printing have the best subjective quality, but the highest costs and environmental impact. Biplots of roughness parameters versus sensorial ranking indicates a significant correlation between maximum peak-to-valley height Rz and tactile and visual perception, while the kurtosis of the topography height distribution Rku correlated best to the hedonic rank.

Physical exercise benefits bone structure and mineralization, especially in children. Immediately following high-impact exercise, PTH increased and returned to resting values within 24 h in both groups, while sclerostin increased in men but not in boys. The underlying mechanisms and implication of this age-related differential response are unclear.

Viral infection in both plant and invertebrate hosts requires a virus-encoded function to block the RNA silencing antiviral defense. Here, we report the identification and characterization of three distinct suppressors of RNA silencing encoded by the approximate to20-kb plus-strand RNA genome of citrus tristeza virus (CTV). When introduced by genetic crosses into plants carrying a silencing transgene, both p20 and p23, but not coat protein (CP), restored expression of the transgene. Although none of the CTV proteins prevented DNA methylation of the transgene, export of the silencing signal (capable of mediating intercellular silencing spread) was detected only from the F, plants expressing p23 and not from the CP- or p20-expressing F, plants, demonstrating suppression of intercellular silencing by CP and p20 but not by p23. Thus, intracellular and intercellular silencing are each targeted by a CTV protein, whereas the third, p20, inhibits silencing at both levels. Notably, CP suppresses intercellular silencing without interfering with intracellular silencing. The novel property of CP suggests a mechanism distinct to p20 and all of the other viral suppressors known to interfere with intercellular silencing and that this class of viral suppressors may not be consistently identified by Agrobacterium coinfiltration because it also induces RNA silencing against the infiltrated suppressor transgene. Our analyses reveal a sophisticated viral counter-defense strategy that targets the silencing antiviral pathway at multiple steps and may be essential for protecting CTV with such a large RNA genome from antiviral silencing in the perennial tree host.

Abstract ZBTB48 (also known as TZAP) is a transcription factor that has previously been reported to bind to telomeres and act as a negative regulator of telomere length in human cell lines. To explore whether transcription factor activity and telomere length regulation are conserved at the organismal level in vertebrates, we generate a zbtb48 −/− zebrafish line via CRISPR‒Cas genome editing. The zbtb48 −/− mutants display no obvious physical or behavioral abnormalities in the first two generations. We find no statistically significant changes in telomere length in first-generation adults. However, for the gene regulatory aspect of Zbtb48, similar to that in human cancer cell lines, we observe downregulation of mtfp1 at both the mRNA and protein levels in the zbtb48 −/− mutants. This suggests that mtfp1 is an evolutionarily conserved regulatory target of Zbtb48. Further investigation of the spatiotemporal expression of zbtb48 in previously published zebrafish data reveals low transcript expression in diverse tissues, except in germline stem cells and gametocytes of the gonads. Notably, Mtfp1 protein downregulation is detected in the ovaries of 40 dpf zbtb48 −/− mutants and in the testes of both 40 dpf and 10.5-month-old zbtb48 −/− mutants.

Abstract Background East African cichlid fishes have diversified in an explosive fashion, but the (epi)genetic basis of the phenotypic diversity of these fishes remains largely unknown. Although transposable elements (TEs) have been associated with phenotypic variation in cichlids, little is known about their transcriptional activity and epigenetic silencing. We set out to bridge this gap and to understand the interactions between TEs and their cichlid hosts. Results Here, we describe dynamic patterns of TE expression in African cichlid gonads and during early development. Orthology inference revealed strong conservation of TE silencing factors in cichlids, and an expansion of piwil1 genes in Lake Malawi cichlids, likely driven by PiggyBac TEs. The expanded piwil1 copies have signatures of positive selection and retain amino acid residues essential for catalytic activity. Furthermore, the gonads of African cichlids express a Piwi-interacting RNA (piRNA) pathway that targets TEs. We define the genomic sites of piRNA production in African cichlids and find divergence in closely related species, in line with fast evolution of piRNA-producing loci. Conclusions Our findings suggest dynamic co-evolution of TEs and host silencing pathways in the African cichlid radiations. We propose that this co-evolution has contributed to cichlid genomic diversity.

Abstract The extracellular parasite Trypanosoma brucei evades the immune system of the mammalian host by periodically exchanging its variant surface glycoprotein (VSG) coat. Hereby, only one VSG gene is transcribed from one of 15 subtelomeric so-called bloodstream form expression sites (BES) at any given timepoint, while all other BESs are silenced. VSG gene expression is altered by homologous recombination using a large VSG gene repertoire or by a so-called in situ switch, which activates a previously silent BES. Transcriptional activation, VSG switching and VSG silencing during developmental differentiation from the bloodstream form to the procyclic form present in the tsetse fly vector are tightly regulated. Due to their subtelomeric position, telomere-associated proteins are involved in the regulation of VSG expression. Three functional homologs of mammalian telomere complex proteins have been characterized thus far, and novel telomere-interacting proteins, such as telomere-associated protein 1 (TelAP1), have recently been identified. Here, we used mass spectrometry-based proteomics and interactomics approaches, telomere pull-down assays with recombinant material and immunofluorescence analysis to elucidate the interactions of 21 other putative TelAPs. We investigated the influence on VSG expression and showed that depletion of TelAPs does not ultimately lead to changes in VSG expression. Additionally, we examined the interaction patterns of four TelAPs with the TbTRF/TbTIF2/TbRAP1 telomere complex by reciprocal affinity purification. We further propose that TelAP1 interacts with Tb927.6.4330, now called TelAP2, and that TelAP1 depends on this interaction to form a complex with the telomeric proteins TbTRF, TbTIF2 and TbRAP1.

Conserved histone methyltransferases of the DOT1 family are involved in replication regulation, cell cycle progression, stage differentiation, and gene regulation in trypanosomatids. However, the specific functions of these enzymes depend on the host evasion strategies of the parasites. In this study, we investigated the role of DOT1B in Leishmania mexicana, focusing on life cycle progression and infectivity. In contrast to Trypanosoma brucei, in which DOT1B is essential for the differentiation of mammal-infective bloodstream forms to insect procyclic forms, L. mexicana DOT1B (LmxDOT1B) is not critical for the differentiation of promastigotes to amastigotes in vitro. Additionally, there are no significant differences in the ability to infect or differentiate in macrophages or sand fly vectors between the LmxDOT1B-depleted and control strains. These findings highlight the divergence of the function of DOT1B in these related parasites, suggesting genus-specific adaptations in the use of histone modifications for life cycle progression and host adaptation processes.

Abstract Cell-cell junctions, and specifically desmosomes, are crucial for robust intercellular adhesion. Desmosomal function is compromised in the autoimmune blistering skin disease pemphigus vulgaris. We combine whole-genome knockout screening and a promotor screen of the desmosomal gene desmoglein 3 in human keratinocytes to identify novel regulators of intercellular adhesion. Kruppel-like-factor 5 (KLF5) directly binds to the desmoglein 3 regulatory region and promotes adhesion. Reduced levels of KLF5 in patient tissue indicate a role in pemphigus vulgaris. Autoantibody fractions from patients impair intercellular adhesion and reduce KLF5 levels in in vitro and in vivo disease models. These effects were dependent on increased activity of histone deacetylase 3, leading to transcriptional repression of KLF5. Inhibiting histone deacetylase 3 increases KLF5 levels and protects against the deleterious effects of autoantibodies in murine and human pemphigus vulgaris models. Together, KLF5 and histone deacetylase 3 are regulators of desmoglein 3 gene expression and intercellular adhesion and represent potential therapeutic targets in pemphigus vulgaris.