Seed-produced anti-globulin VHH-Fc antibodies retrieve globulin precursors in the insoluble fraction and modulate the Arabidopsis thaliana seed subcellular morphology

Key message Nanobody-heavy chain (VHH-Fc) antibody formats have the potential to immunomodulate even highly accumulating proteins and provide a valuable tool to experimentally modulate the subcellular distribution of seed storage proteins. Recombinant antibodies often obtain high accumulation levels in plants, and thus, besides being the actual end-product, antibodies targeting endogenous host proteins can be used to interfere with the localization and functioning of their corresponding antigens. Here, we compared the effect of a seed-expressed nanobody-heavy chain (VHH-Fc) antibody against the highly abundant Arabidopsis thaliana globulin seed storage protein cruciferin with that of a VHH-Fc antibody without endogenous target. Both antibodies reached high accumulation levels of around 10% of total soluble protein, but strikingly, another significant part was present in the insoluble protein fraction and was recovered only after extraction under denaturing conditions. In seeds containing the anti-cruciferin antibodies but not the antibody without endogenous target, the amount of soluble, processed globulin subunits was severely reduced and a major part of the cruciferin molecules was found as precursor in the insoluble fraction. Moreover, in these seeds, aberrant vacuolar phenotypes were observed that were different from the effects caused by the depletion of globulins in knock-out seeds. Remarkably, the seeds with strongly reduced globulin amounts are fully viable and germinate with frequencies similar to wild type, illustrating how flexible seeds can retrieve amino acids from the stored proteins to start germination

Chloroplasts are central players in sugar-induced leaf growth

Leaves are the plant's powerhouses, providing energy for all organs through sugar production during photosynthesis. However, sugars serve not only as a metabolic energy source for sink tissues but also as signaling molecules, affecting gene expression through conserved signaling pathways to regulate plant growth and development. Here, we describe an in vitro experimental assay, allowing one to alter the sucrose (Suc) availability during early Arabidopsis (Arabidopsis thaliana) leaf development, with the aim to identify the affected cellular and molecular processes. The transfer of seedlings to Suc-containing medium showed a profound effect on leaf growth by stimulating cell proliferation and postponing the transition to cell expansion. Furthermore, rapidly after transfer to Suc, mesophyll cells contained fewer and smaller plastids, which are irregular in shape and contain fewer starch granules compared with control mesophyll cells. Short-term transcriptional responses after transfer to Suc revealed the repression of well-known sugar-responsive genes and multiple genes encoded by the plastid, on the one hand, and up-regulation of a GLUCOSE-6-PHOSPHATE TRANSPORTER (GPT2), on the other hand. Mutant gpt2 seedlings showed no stimulation of cell proliferation and no repression of chloroplast-encoded transcripts when transferred to Suc, suggesting that GPT2 plays a critical role in the Suc-mediated effects on early leaf growth. Our findings, therefore, suggest that induction of GPT2 expression by Suc increases the import of glucose-6-phosphate into the plastids that would repress chloroplast-encoded transcripts, restricting chloroplast differentiation. Retrograde signaling from the plastids would then delay the transition to cell expansion and stimulate cell proliferation

Endovascular Repair of Inflammatory Abdominal Aortic Aneurysms with Special Reference to Concomitant Ureteric Obstruction

AbstractObjectives: to study the technical feasibility and results of endovascular treatment of inflammatory abdominal aortic aneurysms (AAA).Design: prospective study.Material and methods: seven patients underwent endovascular repair of an inflammatory AAA. Five patients (8 ureters) were treated with ureteric stents CT scans were obtained one year.Results: the early technical success rate was 100%. Four ureters remained entrapped at one year. Partial regression of periaortic fibrosis was documented in three patients, while four patients showed no regression.Conclusion: endovascular reconstruction of inflammatory abdominal aneurysms is technically feasible. Further study is warranted with regard to the evolution of the periaortic fibrosis and the possible benefits for patients with concomitant hydronephrosis

Practical points of attention beyond instructions for use with the Zenith fenestrated stent graft.

Fenestrated stent grafting for endovascular repair (F-EVAR) aims to treat patients with abdominal aortic aneurysms that are unsuitable for standard EVAR because of a short or absent infrarenal neck. F-EVAR has been used initially in patients with higher surgical risk with pararenal abdominal aortic aneurysms, but F-EVAR is now increasingly considered a treatment alternative to open surgery in anatomically suitable patients. F-EVAR has benefitted from ongoing technical refinements and accumulating clinical experience but remains a relatively complex procedure. Correct indication, accurate preoperative planning, and meticulous execution are the key to long-term success. Considering the growing interest in F-EVAR worldwide, including the United States, we discuss current indications and provide advice for planning and technical execution on the basis of the senior authors' 13 years of experience

Segmental Arterial Mediolysis

Teaching Point: Segmental arterial mediolysis is a rare cause of acute abdominal pain due to dissection and/or aneurysm formation in visceral arteries with subsequent stenosis, occlusion, or haemorrhage

Nota’s nemen in 16de-eeuws Leuven: Een database van tekstboeken uit het Drietalencollege

De afgelopen twintig jaar heeft het onderzoek naar (studenten)notities in vroegmoderne tekstedities een enorme groei gekend. Hoewel deze recente studies tot belangrijke inzichten in de lespraktijk hebben geleid, blijven het vaak ad hoc-analyses die (1) diepgaandere implicaties over het studieobject achterwege laten en (2) een traditionele gevalspecifieke methodologie hanteren. Ons onderzoeksproject “Ad fontes!” in the Classroom (gefinancierd door KU Leuven & FWO) beoogt een meer algemeen kader uit te tekenen om geannoteerde studentenhandboeken op een systematischere manier te onderzoeken. In het bijzonder verkent het project de mogelijkheden van een relationele databank, die de volgende gegevens wil opnemen en open access beschikbaar wil maken voor de casus van het Leuvense Collegium Trilingue te Leuven in de 16de eeuw, een academische instelling waar gratis Latijn, Grieks en Hebreeuws werden onderwezen: (1) de edities van alle studentenhandboeken die aan het Trilingue circuleerden; (2) individuele geannoteerde exemplaren van deze edities; (3) individuele annotaties. De focus ligt op bronnen die het 16de-eeuwse onderricht van Vergilius, Homerus en het Bijbelboek Psalmen reflecteren. De studentenotities worden getranscribeerd, vertaald en met relevante metadata getagd (aard van de annotatie, bronnen, aantal woorden, etc.). Deze aanpak zal ons in staat stellen om op doordachte wijze onze datasets te ordenen en om gemakkelijk kwantitatieve data over de notities te genereren en er een typologie van op te stellen. Tijdens onze presentatie zullen we voornamelijk focussen op de structuur van de databank. Met enkele welgekozen voorbeelden willen we de praktische werking van de databank duiden, alsook illustreren welke data opgevraagd kunnen worden – data die voordien veel moeilijker waren om te verkrijgen. We staan in het bijzonder stil bij in het oog springende of problematische boekhistorische aspecten