Search

Your search keyword '"Niemann, Heiner"' showing total 267 results
Start Over Author "Niemann, Heiner" Search Limiters Peer Reviewed
267 results on '"Niemann, Heiner"'

2. Stem cell-derived porcine macrophages as a new platform for studying host-pathogen interactions

Author

Meek, Stephen, Watson, Tom, Eory, Lel, McFarlane, Gus, Wynne, Felicity J., McCleary, Stephen, Dunn, Laura E. M., Charlton, Emily M., Craig, Chloe, Shih, Barbara, Regan, Tim, Taylor, Ryan, Sutherland, Linda, Gossner, Anton, Chintoan-Uta, Cosmin, Fletcher, Sarah, Beard, Philippa M., Hassan, Musa A., Grey, Finn, Hope, Jayne C., Stevens, Mark P., Nowak-Imialek, Monika, Niemann, Heiner, Ross, Pablo J., Tait-Burkard, Christine, Brown, Sarah M., Lefevre, Lucas, Thomson, Gerard, McColl, Barry W., Lawrence, Alistair B., Archibald, Alan L., Steinbach, Falko, Crooke, Helen R., Gao, Xuefei, Liu, Pentao, and Burdon, Tom

Published
2022
Full Text
View/download PDF

7. Establishment of porcine and human expanded potential stem cells

Author

Gao, Xuefei, Nowak-Imialek, Monika, Chen, Xi, Chen, Dongsheng, Herrmann, Doris, Ruan, Degong, Chen, Andy Chun Hang, Eckersley-Maslin, Melanie A., Ahmad, Shakil, Lee, Yin Lau, Kobayashi, Toshihiro, Ryan, David, Zhong, Jixing, Zhu, Jiacheng, Wu, Jian, Lan, Guocheng, Petkov, Stoyan, Yang, Jian, Antunes, Liliana, Campos, Lia S., Fu, Beiyuan, Wang, Shengpeng, Yong, Yu, Wang, Xiaomin, Xue, Song-Guo, Ge, Liangpeng, Liu, Zuohua, Huang, Yong, Nie, Tao, Li, Peng, Wu, Donghai, Pei, Duanqing, Zhang, Yi, Lu, Liming, Yang, Fengtang, Kimber, Susan J., Reik, Wolf, Zou, Xiangang, Shang, Zhouchun, Lai, Liangxue, Surani, Azim, Tam, Patrick P. L., Ahmed, Asif, Yeung, William Shu Biu, Teichmann, Sarah A., Niemann, Heiner, and Liu, Pentao

Published
2019
Full Text
View/download PDF

12. Genetic knockout of porcine GGTA1 or CMAH/GGTA1 is associated with the emergence of neo‐glycans.

Author

Morticelli, Lucrezia, Rossdam, Charlotte, Cajic, Samanta, Böthig, Dietmar, Magdei, Mikhail, Tuladhar, Sugat Ratna, Petersen, Björn, Fischer, Konrad, Rapp, Erdmann, Korossis, Sotirios, Haverich, Axel, Schnieke, Angelika, Niemann, Heiner, Buettner, Falk F. R., and Hilfiker, Andres

Subjects
GLYCANS, CAPILLARY electrophoresis, ORGANS (Anatomy), LASER-induced fluorescence, TRANSPLANTATION of organs, tissues, etc.
Abstract

Background: Pig‐derived tissues could overcome the shortage of human donor organs in transplantation. However, the glycans with terminal α‐Gal and Neu5Gc, which are synthesized by enzymes, encoded by the genes GGTA1 and CMAH, are known to play a major role in immunogenicity of porcine tissue, ultimately leading to xenograft rejection. Methods: The N‐glycome and glycosphingolipidome of native and decellularized porcine pericardia from wildtype (WT), GGTA1‐KO and GGTA1/CMAH‐KO pigs were analyzed by multiplexed capillary gel electrophoresis coupled to laser‐induced fluorescence detection. Results: We identified biantennary and core‐fucosylated N‐glycans terminating with immunogenic α‐Gal‐ and α‐Gal‐/Neu5Gc‐epitopes on pericardium of WT pigs that were absent in GGTA1 and GGTA1/CMAH‐KO pigs, respectively. Levels of N‐glycans terminating with galactose bound in β(1‐4)‐linkage to N‐acetylglucosamine and their derivatives elongated by Neu5Ac were increased in both KO groups. N‐glycans capped with Neu5Gc were increased in GGTA1‐KO pigs compared to WT, but were not detected in GGTA1/CMAH‐KO pigs. Similarly, the ganglioside Neu5Gc‐GM3 was found in WT and GGTA1‐KO but not in GGTA1/CMAH‐KO pigs. The applied detergent based decellularization efficiently removed GSL glycans. Conclusion: Genetic deletion of GGTA1 or GGTA1/CMAH removes specific epitopes providing a more human‐like glycosylation pattern, but at the same time changes distribution and levels of other porcine glycans that are potentially immunogenic. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

30. Probing the mechanistic role of glutamate residue in the zinc-binding motif of type A botulinum neurotoxin light chain

Author

Li, Li, Binz, Thomas, Niemann, Heiner, and Singh, Bal Ram

Subjects
Botulinum toxin -- Research, Enzymes -- Structure-activity relationship, Biological sciences, Chemistry
Abstract

The glutamate-224 residue in the light chain of type A botulinum toxin is essential for activity. Replacing Glu-224 with Asp causes complete loss of activity, indicating the importance of a carboxyl group at that position.

Published
2000

41. Immunological and functional features of decellularized xenogeneic heart valves after transplantation into GGTA1-KO pigs.

Author

Ramm, Robert, Goecke, Tobias, Köhler, Peter, Tudorache, Igor, Cebotari, Serghei, Ciubotaru, Anatol, Sarikouch, Samir, Höffler, Klaus, Bothe, Friederike, Petersen, Björn, Haverich, Axel, Niemann, Heiner, and Hilfiker, Andres

Subjects
HEART valves, REGENERATIVE medicine, GALACTOSYLTRANSFERASES, FOREIGN body reaction, ANTIBODY titer
Abstract

Decellularization of xenogeneic heart valves might lead to excellent regenerative implants, from which many patients could benefit. However, this material carries various xenogeneic epitopes and thus bears a considerable inherent immunological risk. Here, we investigated the regenerative and immunogenic potential of xenogeneic decellularized heart valve implants using pigs deficient for the galactosyltransferase gene (GGTA1-KO) as novel large animal model. Decellularized aortic and pulmonary heart valves obtained from sheep, wild-type pigs or GGTA1-KO pigs were implanted into GGTA1-KO pigs for 3, or 6 months, respectively. Explants were analyzed histologically, immunhistologically (CD3, CD21 and CD172a) and anti-αGal antibody serum titers were determined by ELISA. Xenogeneic sheep derived implants exhibited a strong immune reaction upon implantation into GGTA1-KO pigs, characterized by massive inflammatory cells infiltrates, presence of foreign body giant cells, a dramatic increase of anti-αGal antibody titers and ultimately destruction of the graft, whereas wild-type porcine grafts induced only a mild reaction in GGTA1-KO pigs. Allogeneic implants, wild-type/wild-type and GGTA1-KO/GGTA1-KO valves did not induce a measurable immune reaction. Thus, GGTA1-KO pigs developed a 'human-like' immune response toward decellularized xenogeneic implants showing that immunogenicity of xenogeneic implants is not sufficiently reduced by decellularization, which detracts from their regenerative potential. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

43. Membrane fusion machinery: insights from synaptic proteins

Author

Sudhof, Thomas C., De Pietro, Camilli, Niemann, Heiner, and Jahn, Reinhard

Subjects
Eukaryotic cells -- Research, Membrane fusion -- Analysis, Proteins -- Research, Biological sciences
Abstract

The basic processes of membrane fusion are maintained consistently between different vesicular pathways in eukaryotic cells. This maintenance is found in yeast cells as well as in mammalian neurons. High levels of standardization are found in the purification, cloning and functional analysis of the synaptic vesicle protein. New proteins, essential for membrane docking and fusion, are revealed by the biochemical characterization of the membrane fusion reactions. The eukaryotes have simpler genetics and involve several proteins in the membrane fusion processes.

Published
1993

44. Botulinum neurotoxin A selectively cleaves the synaptic protein SNAP-25

Author

Blasi, Juan, Chapman, Edwin R., Link, Egenhard, Binz, Thomas, Shinji Yamasaki, Camilli, Pietro de, Sudhof, Thomas C., Niemann, Heiner, and Jahn, Reinhard

Subjects
Botulinum toxin -- Influence, Neurotransmitters -- Analysis, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Botulinum neurotoxin type A (BoNT/A) blocks the release of transmitters from synaptosomes due to selective cleaving of SNAP-25. Selective proteolysis of SNAP-25, the synaptic protein, is demonstrated by BoNT/A, which behaves as a zinc dependant protease. Sensitivity to divalent cation chelators was observed and cleavage was noticed near the carboxyterminus.

Published
1993

45. Cellubrevin is a ubiquitous tetanus-toxin substrate homologous to a putative synaptic vesicle fusion protein

Author

McMahon, Harvey T., Ushkaryov, Yuri A., Edelmann, Lambert, Link, Egenhard, Binz, Thomas, Niemann, Heiner, Jahn, Reinhard, and Sudhof, Thomas C.

Subjects
Membrane proteins -- Research, Neural transmission -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Constitutive and regulated vesicular pathways appear to use homologous proteins for membrane trafficking, suggesting that the two are closer in evolution and mechanism than once thought. Cellubrevin is a new synaptobrevin analog that appeared in all tissues and cells tested, that is as vulnerable to tetanus toxin as synaptobrevin, and that is a membrane trafficking protein of a constitutively recycling pathway.

Published
1993

48. Melatonin improves rate of monospermic fertilization and early embryo development in a bovine IVF system.

Author

Gutiérrez-Añez, Juan Carlos, Henning, Heiko, Lucas-Hahn, Andrea, Baulain, Ulrich, Aldag, Patrick, Sieg, Birgit, Hensel, Vivian, Herrmann, Doris, and Niemann, Heiner

Subjects
EMBRYOLOGY, EMBRYOS, BIOLOGICAL systems, MELATONIN, FERTILIZATION in vitro, OVUM, SPERM competition
Abstract

The developmental competence of male and female gametes is frequently reduced under in vitro conditions, mainly due to oxidative stress during handling. The amino-acid derived hormone melatonin has emerged as a potent non-enzymatic antioxidant in many biological systems. The goal of the present study was to evaluate the effects of melatonin on post-thaw sperm quality, fertilizing ability, and embryo development and competence in vitro after in vitro fertilization. Frozen-thawed bovine spermatozoa were incubated either in the presence of 10−11 M melatonin (MT), or its solvent (ethanol; Sham-Control), or plain Tyrode's Albumin Lactate Pyruvate medium (TALP, Control). Computer-Assisted Sperm Analysis (CASA) and flow cytometry data after 30 min, 120 min, and 180 min incubation did not reveal any significant effects of melatonin on average motility parameters, sperm subpopulation structure as determined by hierarchical cluster, or on the percentage of viable, acrosome intact sperm, or viable sperm with active mitochondria. Nevertheless, in vitro matured cumulus-oocyte-complexes fertilized with spermatozoa which had been preincubated with 10−11 M melatonin (MT-Sperm) showed higher (P < 0.01) rates of monospermic fertilization, reduced (P < 0.05) polyspermy and enhanced (P < 0.05) embryo development compared to the Control group. Moreover, the relative abundance of MAPK13 in the in vitro-derived blastocysts was greater (P < 0.05) than observed in the Control group. In conclusion, adding melatonin to the sperm-preparation protocol for bovine IVF improved proper fertilization and enhanced embryonic development and competence in vitro. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results