Immunocompetence in Hydra. Epithelial cells recognize self-nonself and react against it

The evolution of effective immunologic defense mechanisms in multicellular organisms involves the ability of host cells to distinguish betweeen self and nonself and to react appropriately to eliminate foreign tissue. By producing interspecies grafts we have obtained evidence that immunorecognition followed by incompatibility reactions occur in Hydra. Our results demonstrate that epithelial cells of Hydra recognize and phagocytose foreign hydra cells, indicating that they are the effector cells in the incompatibility reactions. This observation is consistent with the idea that immunocompetence appeared early in the evolution of multicellular organisms

The Impact of the Long-Distance Transport of a BEL1-Like Messenger RNA on Development

BEL1- and KNOTTED1-type proteins are transcription factors from the three-amino-loop-extension superclass that interact in a tandem complex to regulate the expression of target genes. In potato (Solanum tuberosum), StBEL5 and its Knox protein partner regulate tuberization by targeting genes that control growth. RNA movement assays demonstrated that StBEL5 transcripts move through the phloem to stolon tips, the site of tuber induction. StBEL5 messenger RNA originates in the leaf, and its movement to stolons is induced by a short-day photoperiod. Here, we report the movement of StBEL5 RNA to roots correlated with increased growth, changes in morphology, and accumulation of GA2-oxidase1, YUCCA1a, and ISOPENTENYL TRANSFERASE transcripts. Transcription of StBEL5 in leaves is induced by light but insensitive to photoperiod, whereas in stolon tips growing in the dark, promoter activity is enhanced by short days. The heterodimer of StBEL5 and POTH1, a KNOTTED1-type transcription factor, binds to a tandem TTGAC-TTGAC motif that is essential for regulating transcription. The discovery of an inverted tandem motif in the StBEL5 promoter with TTGAC motifs on opposite strands may explain the induction of StBEL5 promoter activity in stolon tips under short days. Using transgenic potato lines, deletion of one of the TTGAC motifs from the StBEL5 promoter results in the reduction of GUS activity in new tubers and roots. Gel-shift assays demonstrate BEL5/POTH1 binding specificity to the motifs present in the StBEL5 promoter and a double tandem motif present in the StGA2-oxidase1 promoter. These results suggest that, in addition to tuberization, the movement of StBEL5 messenger RNA regulates other aspects of vegetative development.Fil: Lin, Tian. University of Iowa; Estados UnidosFil: Sharma, Pooja. University of Iowa; Estados UnidosFil: Gonzalez, Daniel Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Viola, Ivana Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Hannapel, David J.. University of Iowa; Estados Unido

Nationwide Registry‐Based Analysis of Infective Endocarditis Risk After Pulmonary Valve Replacement

Background: Infective endocarditis (IE) after pulmonary valve replacements in congenital heart disease is a significant concern. This study aimed to identify specific long-term risk factors for IE after percutaneous pulmonary valve implantation or surgical pulmonary valve replacement. Methods and Results: All patients with congenital heart disease from the National Register for Congenital Heart Defects with at least 1 pulmonary valve replacement before January 2018 were included. A total of 1170 patients (56.3% men, median age at study inclusion 12 [interquartile range {Q1-Q3} 5-20 years]) received 1598 pulmonary valve replacements. IE occurred in 4.8% of patients during a follow-up of total 9397 patient-years (median 10 [Q1-Q3, 6-10] years per patient). After homograft implantation 7 of 558 (1.3%) patients developed IE, after heterograft implantation 31 of 723 (4.3%) patients, and after Melody valve implantation 18 of 241 (7.5%) patients. Edwards Sapien and mechanical valves were used less frequently and remained without IE. The incidence of IE in heterografts excluding Contegra valves was 7 of 278 (2.5%), whereas the incidence of IE in Contegra valves was 24 of 445 (5.4%). The risk of IE was not increased compared with homografts if Contegra valves were excluded from the heterografts (hazard ratio [HR], 2.60; P=0.075). The risk of IE was increased for bovine jugular vein valves, Contegra valves (HR, 6.72; P<0.001), and Melody valves (HR, 5.49; P<0.001), but did not differ between Melody valves and Contegra valves (HR, 1.01; P=0.978). Conclusions: Bovine jugular vein valves have the highest risk of IE, irrespective of the mode of deployment, either surgical or percutaneous

Dissecting grapevine graft incompatibility with particular reference to its early detection and underlying causes

"Grafting is an ancient agricultural method widely practice already in Greek and Roman times and consists in the joining of two different plant parts, the scion (shoot) and the rootstock (roots), in a way in which they will develop and functioning as a single plant. Over time, grafting evolved from a way of propagating plants to using them to improve their characteristics. For instance, Vitis vinifera are grafted since the middle of the 19th century onto American grapevine rootstocks to exploit their resistance to the Phylloxera, which would otherwise be lethal for European vines. One important aspect of grafting is graft incompatibility which refers to the early or later failure of the graft union which delays rootstock breeding selection and causes losses to farmers and nurseries.(...)