Search results for "CLEAVAGE"

Embryo multinucleation at the two-cell stage is an independent predictor of intracytoplasmic sperm injection outcomes.

2016

Objective To determine the prognostic impact of the nuclear status at the two-cell stage on intracytoplasmic sperm injection (ICSI) outcomes. Design Retrospective study. Setting Hospital. Patient(s) Only ICSI cycles with time-lapse monitoring of transferred embryos with known implantation/delivery data from November 2012 to December 2014 were included. A total of 2,449 embryos were assessed for multinucleation rates at the two- and four-cell stage, and 608 transferred embryos were studied for ICSI outcomes. Intervention(s) None. Main Outcome Measure(s) Implantation rate (IR) and live birth rate (LBR) according to the number of multinucleated blastomeres at the two-cell stage: none (Without-…

Ectodomain shedding of CD99 within highly conserved regions is mediated by the metalloprotease meprin β and promotes transendothelial cell migration.

2016

The adhesion molecule CD99 is essential for the transendothelial migration of leukocytes. In this study, we used biochemical and cellular assays to show that CD99 undergoes ectodomain shedding by the metalloprotease meprin β and subsequent intramembrane proteolysis by γ-secretase. The cleavage site in CD99 was identified by mass spectrometry within an acidic region highly conserved through different vertebrate species. This finding fits perfectly to the unique cleavage specificity of meprin β with a strong preference for aspartate residues and suggests coevolution of protease and substrate. We hypothesized that limited CD99 cleavage by meprin β would alter cellular transendothelial migratio…

Structural and functional insights into lysostaphin–substrate interaction

2018

Lysostaphin from Staphylococcus simulans and its family enzymes rapidly acquire prominence as the next generation agents in treatment of S. aureus infections. The specificity of lysostaphin is promoted by its C-terminal cell wall targeting domain selectivity towards pentaglycine bridges in S. aureus cell wall. Scission of these cross-links is carried out by its N-terminal catalytic domain, a zinc-dependent endopeptidase. Understanding the determinants affecting the efficiency of catalysis and strength and specificity of interactions lies at the heart of all lysostaphin family enzyme applications. To this end, we have used NMR, SAXS and molecular dynamics simulations to characterize lysostap…

2020

AbstractDeveloping methods for accurate detection of RNA modifications remains a major challenge in epitranscriptomics. Next-generation sequencing-based mapping approaches have recently emerged but, often, they are not quantitative and lack specificity. Pseudouridine (ψ), produced by uridine isomerization, is one of the most abundant RNA modification. ψ mapping classically involves derivatization with soluble carbodiimide (CMCT), which is prone to variation making this approach only semi-quantitative. Here, we developed ‘HydraPsiSeq’, a novel quantitative ψ mapping technique relying on specific protection from hydrazine/aniline cleavage. HydraPsiSeq is quantitative because the obtained sign…

Electrochemical modifications of proteins: disulfide bonds reduction

2002

International audience; Electrochemical reduction of lysozyme disulfide bonds was achieved at pH between 10 and 11.Below pH 10, no disulfide bond cleavage was observed. At pH higher than 12, the cleavage of disulfide bonds is essentially due to hydrolysis. The addition of denaturant considerably enhanced the performance of the electrochemical device.

A detailed identification study on high-temperature degradation products of oleic and linoleic acid methyl esters by GC–MS and GC–FTIR

2012

GC-MS and GC-FTIR were complementarily applied to identify oxidation compounds formed under frying conditions in methyl oleate and linoleate heated at 180ºC. The study was focused on the compounds that originated through hydroperoxide scission that remain attached to the glyceridic backbone in fats and oils and form part of non-volatile molecules. Twenty one short-chain esterified compounds, consisting of 8 aldehydes, 3 methyl ketones, 4 primary alcohols, 5 alkanes and 1 furan, were identified. In addition, twenty non-esterified volatile compounds, consisting of alcohols, aldehydes and acids, were also identified as major non-esterified components. Furanoid compounds of 18 carbon atoms form…

Mucin induces CRISPR-Cas defense in an opportunistic pathogen

2022

It is unknown what circumstances promote particular bacterial defenses against bacterial viruses (phages). Almeida & Hoikkala et al. show that mucin, derived from mucus, greatly accelerates CRISPR-Cas defenses against phage in an opportunistic pathogen. Parasitism by bacteriophages has led to the evolution of a variety of defense mechanisms in their host bacteria. However, it is unclear what factors lead to specific defenses being deployed upon phage infection. To explore this question, we co-evolved the bacterial fish pathogen Flavobacterium columnare and its virulent phage V156 in presence and absence of a eukaryotic host signal (mucin) for sixteen weeks. The presence of mucin leads to a …

Intracytoplasmic sperm injection with cryopreserved testicular spermatozoa

2001

To assess if testicular sperm cryopreservation is a valid alternative to repetition of testicular sperm retrieval techniques, results of a cryopreservation technique in pills have been retrospectively analyzed. Enough motile spermatozoa for ICSI were obtained in 172 from 190 (90.5%) frozen-thawed testicular sperm samples. Overall, 249 couples underwent 390 ICSI cycles, 156 using fresh and 234 using cryopreserved testicular sperm. Mean two-pronuclear fertilization rates per cycle were not significantly different after ICSI with fresh (62.0%) or with cryopreserved (63.2%) spermatozoa. Mean embryo cleavage rate per cycle was higher in the fresh (90.6%) than in the cryopreserved (84.6%) group (…

Limited implantation success of direct-cleaved human zygotes: a time-lapse study.

2012

Objective To evaluate embryos with direct cleavage (≤5 hours) from two to three cells (DC2–3) and correlate this morphokinetic parameter to implantation and ongoing pregnancy. Design Clinical multicenter retrospective study. Setting Private in vitro fertilization (IVF) centers. Patient(s) From three clinics, a total of 979 treatments including 5,225 embryos using autologous or donated oocytes, of which 1,659 embryos were transferred. Intervention(s) None. Main Outcome Measure(s) Clinical pregnancy confirmed by ultrasound in week 7. Result(s) Of the total embryo cohort, 715 (13.7%) underwent direct cleavage from two to three cells, 1,659 embryos were transferred to recipients, and 109 of the…

Imidazolsynthesen, 10. Mitt. Zur selektiven Synthese N-substituierter Imidazol-4-äthanole

1977

Die Synthese N-substituierter Methoxyathylimidazole 5, 6 aus Aldehyden 1, 1-Hydroxy-4-methoxy-2-butanon (2), primaren Aminen 3 und Ammoniak (4) nach Weidenhagen liefert Gemische, in denen im GC die 1,4-Isomere 5 in der Regel deutlich uberwiegen. Aus diesen lassen sich durch Atherspaltung mit HJ die N-substituierten Imidazol-4-athanole 8 erhalten. Selective Synthesis of N-Substituted Imidazole-4-ethanols The synthesis of N-substituted methoxyethylimidazoles 5, 6 from aldehydes 1, 1-hydroxy-4-methoxy-2-butanone (2), primary amines 3, and ammonia (4), using the Weidenhagen cyclisation, yields mixtures in which, according to gc analysis, the 1,4-isomers 5 prevail. Ether cleavage with HI gives t…