1
|
Severin F, Fusi GM, Wartmann C, Neudörfl J, Berkessel A. syn
‐Selective Epoxidation of Chiral Terminal Allylic Alcohols with a Titanium Salalen Catalyst and Hydrogen Peroxide. Angew Chem Int Ed Engl 2022; 61:e202201790. [PMID: 35349213 PMCID: PMC9325473 DOI: 10.1002/anie.202201790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Indexed: 12/02/2022]
Abstract
In the Sharpless asymmetric epoxidation of chiral secondary allylic alcohols, one substrate enantiomer is predominantly converted to the anti‐epoxy alcohol. We herein report the first highly syn‐selective epoxidation of terminal allylic alcohols using a titanium salalen complex as catalyst, at room temperature, and aqueous hydrogen peroxide as oxidant. With enantiopure terminal allylic alcohols as substrates, the epoxy alcohols were obtained with up to 98 % yield and up to >99 : 1 dr (syn). Catalyst loadings as low as 1 mol % can be applied without eroding the syn‐diastereoselectivity. Modification of the allylic alcohol to an ether does not affect the diastereoselectivity either [>99 : 1 dr (syn)]. Inverting the catalyst configuration leads to the anti‐product, albeit at lower dr (ca. 20 : 1). The synthetic potential is demonstrated by a short, gram‐scale preparation of a tetrahydrofuran building block with three stereocenters, involving two titanium salalen catalyzed epoxidation steps.
Collapse
Affiliation(s)
- Fabian Severin
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| | - Giovanni M. Fusi
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
- Dipartimento di Scienza e Alta Tecnologia—DiSAT Università degli Studi dell'Insubria Via Valleggio 9 22100 Como Italy
| | - Christina Wartmann
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| | - Jörg‐Martin Neudörfl
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| | - Albrecht Berkessel
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| |
Collapse
|
2
|
Severin F, Fusi GM, Wartmann C, Neudörfl J, Berkessel A. syn
‐Selective Epoxidation of Chiral Terminal Allylic Alcohols with a Titanium Salalen Catalyst and Hydrogen Peroxide. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Fabian Severin
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| | - Giovanni M. Fusi
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
- Dipartimento di Scienza e Alta Tecnologia—DiSAT Università degli Studi dell'Insubria Via Valleggio 9 22100 Como Italy
| | - Christina Wartmann
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| | - Jörg‐Martin Neudörfl
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| | - Albrecht Berkessel
- Department of Chemistry Organic Chemistry University of Cologne Greinstraße 4 50939 Cologne Germany
| |
Collapse
|
3
|
Sadler J, Shapoori K, Malyarenko E, Severin F, Maev RG. Locating an acoustic point source scattered by a skull phantom via time reversal matched filtering. J Acoust Soc Am 2010; 128:1812-1822. [PMID: 20968354 DOI: 10.1121/1.3479550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper examines the utilization of the time reversal matched filtering method to resolve the location of an acoustic point source beneath a skull phantom (variable thickness layer), without the removal of this layer. This acoustical process is examined experimentally in a water tank immersion system containing an acoustic source, a custom-made skull phantom, and a receiving transducer in a pitch-catch arrangement. The phantom is designed to approximately model the acoustic properties of an average human skull bone (minus the diploe layer), while the variable thickness of the phantom introduces a variable time delay to the acoustic wave, relative to its entry point on the phantom. This variable delay is measured and corrected for, and a matched filtering time reversed process is used to determine the location of the point source. The results of the experiment are examined for various positions of the acoustic source behind the phantom and compared to the reference cases with no phantom present. The average distance between these two cases is found to be 4.36 mm, and within the expected deviation in results due to not accounting for the effects of refraction.
Collapse
Affiliation(s)
- J Sadler
- Institute for Diagnostic Imaging Research, 688 University Avenue West, Windsor, Ontario N9A 5R5, Canada.
| | | | | | | | | |
Collapse
|
4
|
Bocharova N, Chave-Cox R, Sokolov S, Knorre D, Severin F. Protein aggregation and neurodegeneration: clues from a yeast model of Huntington's disease. Biochemistry (Mosc) 2009; 74:231-234. [PMID: 19267681 DOI: 10.1134/s0006297909020163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A number of neurodegenerative diseases are accompanied by the appearance of intracellular protein aggregates. Huntington's disease (HD) is caused by a mutation in a gene encoding huntingtin. The mutation causes the expansion of the polyglutamine (polyQ) domain and consequently polyQ-containing aggregates accumulate and neurons in the striatum die. The role of the aggregates is still not clear: they may be the cause of cytotoxicity or a manifestation of the cellular attempt to remove the misfolded proteins. There is accumulating evidence that the main cause of HD is the interaction of the mutated huntingtin with other polyQ-containing proteins and molecular chaperones and most studies based on a yeast model of HD support this point of view. Data obtained using yeasts suggest pathological consequences of polyQ-proteasomal interaction: proteasomal overload by polyQs may interfere with functions of the cell cycle-regulating proteins.
Collapse
|
5
|
Lebailly P, Devaux A, Pottier D, De Meo M, Andre V, Baldi I, Severin F, Bernaud J, Durand B, Henry-Amar M, Gauduchon P. Urine mutagenicity and lymphocyte DNA damage in fruit growers occupationally exposed to the fungicide captan. Occup Environ Med 2003; 60:910-7. [PMID: 14634181 PMCID: PMC1740442 DOI: 10.1136/oem.60.12.910] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS To determine haematological parameters, urine mutagenicity (on three Salmonella typhimurium strains), and DNA damage (using the comet assay) in mononuclear leucocytes of farmers before and after a one-day spraying period of pear and apple trees with the fungicide captan in usual conditions. METHODS Fruit growers were exposed to captan during the 1998 (n = 12) and/or the 2000 spraying seasons (n = 17). Biological samples were collected on the morning of the day of spraying (S1), the evening after spraying (S2), and the morning of the day after (S3). The UK Predictive Operator Exposure Model (UK-POEM) was used to quantify pesticide exposure intensity. RESULTS No effect was observed on haematological parameters for these two spraying seasons. Proportions of mutagenic urine samples did not significantly differ between S1 and S2/S3 sampling points. In contrast with strains TA97a and YG1041 mainly sensitive to frameshift mutations, a positive trend was observed between the difference (S3-S1) of mutagenic power on strain TA102 detecting base-pair mutations and the exposure predicted value given by UK-POEM, mainly due to parameters related to protective clothing. No significant variations in DNA damage levels were observed between S1 and S3, nor were correlations observed with parameters of pesticide exposure. CONCLUSIONS A one-day spraying period with captan and other pesticides does not significantly induce DNA damages in mononuclear leucocytes. In contrast, an inefficient protective clothing could correlate with an increase in urine mutagenicity as assessed by the TA102 tester strain.
Collapse
Affiliation(s)
- P Lebailly
- GRECAN (EA-1772), Université de Caen, 14076 CAEN Cedex 5, France.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Severin F, Hyman AA, Piatti S. Correct spindle elongation at the metaphase/anaphase transition is an APC-dependent event in budding yeast. J Cell Biol 2001; 155:711-8. [PMID: 11724813 PMCID: PMC2150857 DOI: 10.1083/jcb.200104096] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2001] [Revised: 10/10/2001] [Accepted: 10/10/2001] [Indexed: 11/22/2022] Open
Abstract
At the metaphase to anaphase transition, chromosome segregation is initiated by the splitting of sister chromatids. Subsequently, spindles elongate, separating the sister chromosomes into two sets. Here, we investigate the cell cycle requirements for spindle elongation in budding yeast using mutants affecting sister chromatid cohesion or DNA replication. We show that separation of sister chromatids is not sufficient for proper spindle integrity during elongation. Rather, successful spindle elongation and stability require both sister chromatid separation and anaphase-promoting complex activation. Spindle integrity during elongation is dependent on proteolysis of the securin Pds1 but not on the activity of the separase Esp1. Our data suggest that stabilization of the elongating spindle at the metaphase to anaphase transition involves Pds1-dependent targets other than Esp1.
Collapse
Affiliation(s)
- F Severin
- Max Planck Institute for Cell Biology and Genetics, Dresden 01307, Germany
| | | | | |
Collapse
|
7
|
Affiliation(s)
- E Nielsen
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse, Dresden, Germany
| | | | | | | |
Collapse
|
8
|
Abstract
The small GTPase Rab5 regulates membrane docking and fusion in the early endocytic pathway. Here we reveal a new role for Rab5 in the regulation of endosome interactions with the microtubule network. Using Rab5 fused to green fluorescent protein we show that Rab5-positive endosomes move on microtubules in vivo. In vitro, Rab5 stimulates both association of early endosomes with microtubules and early-endosome motility towards the minus ends of microtubules. Moreover, similarly to endosome membrane docking and fusion, Rab5-dependent endosome movement depends on the phosphatidylinositol-3-OH kinase hVPS34. Thus, Rab5 functionally links regulation of membrane transport, motility and intracellular distribution of early endosomes.
Collapse
Affiliation(s)
- E Nielsen
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse, Dresden D-01307, Germany
| | | | | | | | | |
Collapse
|
9
|
Affiliation(s)
- F Severin
- Cell Biology Program, EMBL, Heidelberg, Germany
| | | | | | | |
Collapse
|
10
|
Müller-Reichert T, Chrétien D, Severin F, Hyman AA. Structural changes at microtubule ends accompanying GTP hydrolysis: information from a slowly hydrolyzable analogue of GTP, guanylyl (alpha,beta)methylenediphosphonate. Proc Natl Acad Sci U S A 1998; 95:3661-6. [PMID: 9520422 PMCID: PMC19892 DOI: 10.1073/pnas.95.7.3661] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Microtubules are dynamic polymers that interconvert between periods of slow growth and fast shrinkage. The energy driving this nonequilibrium behavior comes from the hydrolysis of GTP, which is required to destabilize the microtubule lattice. To understand the mechanism of this destabilization, cryo-electron microscopy was used to compare the structure of the ends of shrinking microtubules assembled in the presence of either GTP or the slowly hydrolyzable analogue guanylyl (alpha,beta)methylenediphosphonate (GMPCPP). Depolymerization was induced by cold or addition of calcium. With either nucleotide, we have observed curled oligomers at the ends of shrinking microtubules. However, GDP oligomers were consistently more curved than GMPCPP oligomers. This difference in curvature between depolymerizing GDP and GMPCPP protofilaments suggests that GTP hydrolysis is accompanied by an increase in curvature of the protofilaments, thereby destabilizing the lateral interactions between tubulin subunits in the microtubule lattice.
Collapse
Affiliation(s)
- T Müller-Reichert
- Cell Biology Program, European Molecular Biology Laboratory, Meyerhofstrasse 1, Postfach 1022.09, D-69117, Heidelberg, Germany.
| | | | | | | |
Collapse
|
11
|
Tobiasch E, Rabreau M, Geletneky K, Laruë-Charlus S, Severin F, Becker N, Schlehofer JR. Detection of adeno-associated virus DNA in human genital tissue and in material from spontaneous abortion. J Med Virol 1994; 44:215-22. [PMID: 7852963 DOI: 10.1002/jmv.1890440218] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The human helper virus-dependent parvovirus, adeno-associated virus (AAV) has never been associated with disease in humans [Berns et al. (1987): Advances in Virus Research 32:243-306; Siegl et al. (1985): Intervirology 23:61-73]. However, in pregnant mice, infection with AAV induces early abortion [Botquin et al. (1993): Journal of Cancer Research and Clinical Oncology 119:24]. We investigated whether this common human virus may be found in human genital tissue or in curettage material from spontaneous abortion. Using the polymerase chain reaction (PCR) AAV type 2 DNA was amplified in histological sections of 19 of 30 biopsies of the uterine mucosa. In addition, AAV-2 DNA was detected in abortion material during the first trimester of pregnancy (12/30 cases were positive) but not in material of abortion from the second or third trimester (9 cases). Whereas in tissues from the uterus AAV DNA was found only by PCR, large amounts of viral DNA were detectable by Southern blot analysis in abortion material. In situ hybridization revealed DNA of AAV to be present in the villous moiety (trophoblast) of the placenta but not in the embryo or decidua. in the same cells, AAV proteins (including the replication-associated rep proteins) were detected by immunofluorescence analysis. These results suggest (1) that AAV infects the uterine mucosa (possibly persistently) and (2) that it can replicate in trophoblast cells. This might disturb placenta development and may play a role in early miscarriage.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- E Tobiasch
- F.S. Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Heidelberg, Germany
| | | | | | | | | | | | | |
Collapse
|
12
|
van der Brempt X, Derue G, Severin F, Colin L, Gilbeau JP, Heller F. Ludwig's angina and mediastinitis due to Streptococcus milleri: usefulness of computed tomography. Eur Respir J 1990; 3:728-31. [PMID: 2379578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Despite intensive use of antibiotics, Ludwig's angina remains a potentially lethal infection because of the risk of upper airway obstruction and spread into the mediastinum. We present two patients who survived mediastinitis complicating Ludwig's angina due to Streptococcus milleri. Computed tomography performed early in the course of the disease detected pus collections and directed appropriate drainage procedures.
Collapse
Affiliation(s)
- X van der Brempt
- Dept of Internal Medicine, Hôpital de Jolimont, Haine-Saint-Paul, Belgium
| | | | | | | | | | | |
Collapse
|
13
|
van der Brempt X, Derue G, Severin F, Colin L, Gilbeau JP, Heller F. Ludwig's angina and mediastinitis due to Streptococcus milleri: usefulness of computed tomography. Eur Respir J 1990. [DOI: 10.1183/09031936.93.03060728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Despite intensive use of antibiotics, Ludwig's angina remains a potentially lethal infection because of the risk of upper airway obstruction and spread into the mediastinum. We present two patients who survived mediastinitis complicating Ludwig's angina due to Streptococcus milleri. Computed tomography performed early in the course of the disease detected pus collections and directed appropriate drainage procedures.
Collapse
|
14
|
Leroux R, Viau G, Hovasse E, Severin F, Sarfati A, Alexandre G, Leroy M, Godon J, Malassenet S, Desroches C. [Architecture and senile dementia]. Soins 1987:47-9. [PMID: 2956689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
15
|
Abstract
In 144 healthy subjects tonic heat stimuli were applied with a contact thermode and systematically varied with respect to 3 parameters: temperature T, rate of temperature change RTC, and duration D. In addition, the stimulus temperature at which the first sensation of pain occurred was produced by some subjects. In both types of experiments, subjects compared heat intensity felt at the beginning and the end of the stimulus and then set stimulus temperature to correspond with their initial sensation. The direction of this temperature change (delta T) indicates whether the subject senses an augmentation or a diminution of heat intensity. There was a parallel occurrence of pain and sensitization to sustained heat. The average skin temperature of the point of transition from adaptation to sensitization was equal to the average pain threshold temperature. The temperature change response maintained individual differences of thermal and pain sensitivity and was highly consistent for each subject. Potential applications of the procedure in clinical and experimental pain research are discussed.
Collapse
Affiliation(s)
- F Severin
- Neurologische Poliklinik, Max-Planck-Institut für Psychiatrie, Kraepelinstrasse 10, 8000 Munich 80 F.R.G
| | | | | |
Collapse
|
16
|
Abstract
By means of experimentally induced heat pain, the effectiveness of transcutaneous electrical nerve stimulation (TNS) was studied in 51 healthy volunteers. TNS produces an elevation of the lower range of sensitiveness to pain ("elevated pain threshold") and hence pain relief. The findings are compared with neurophysiological results from leads of polymodal human C-fibres and spinothalamic tract (dorsal horn) neurons. Their importance for clinical pain syndromes is discussed.
Collapse
|
17
|
Strian F, Severin F, Müller J, Montag N. [Diagnosis of painful diabetic small fiber neuropathy using temperature sense thresholds]. Nervenarzt 1984; 55:103-7. [PMID: 6700800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
18
|
Maurach R, Severin F, Strian F. [Quantitative studies on stereoesthesia (author's transl)]. Fortschr Neurol Psychiatr 1982; 50:121-6. [PMID: 7095720 DOI: 10.1055/s-2007-1002256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|