Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
EMBO J ; 42(13): e113004, 2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-37211994

RESUMO

Soil salinity impairs plant growth reducing crop productivity. Toxic accumulation of sodium ions is counteracted by the Salt Overly Sensitive (SOS) pathway for Na+ extrusion, comprising the Na+ transporter SOS1, the kinase SOS2, and SOS3 as one of several Calcineurin-B-like (CBL) Ca2 + sensors. Here, we report that the receptor-like kinase GSO1/SGN3 activates SOS2, independently of SOS3 binding, by physical interaction and phosphorylation at Thr16. Loss of GSO1 function renders plants salt sensitive and GSO1 is both sufficient and required for activating the SOS2-SOS1 module in yeast and in planta. Salt stress causes the accumulation of GSO1 in two specific and spatially defined areas of the root tip: in the endodermis section undergoing Casparian strip (CS) formation, where it reinforces the CIF-GSO1-SGN1 axis for CS barrier formation; and in the meristem, where it creates the GSO1-SOS2-SOS1 axis for Na+ detoxification. Thus, GSO1 simultaneously prevents Na+ both from diffusing into the vasculature, and from poisoning unprotected stem cells in the meristem. By protecting the meristem, receptor-like kinase-conferred activation of the SOS2-SOS1 module allows root growth to be maintained in adverse environments.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Sódio/metabolismo , Nicho de Células-Tronco , Estresse Salino , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/metabolismo
2.
Psychother Psychosom Med Psychol ; 74(3-04): 103-111, 2024 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-38552616

RESUMO

The negative attitude of psychotherapists towards the treatment of older patients in the past has weakened in the recent past. Nevertheless, the question remains as to how therapists perceive older patients in comparison to younger patients, what clinical judgements they arrive at and how they perceive the relationship with them. In the present study, which was conducted as part of the ÄPP study (Older Patients in Psychotherapy), therapists were asked to assess a self-selected younger (<40 years) or an older patient (>65) with regard to various variables. A total of 527 completed questionnaires were available. Two-factor analyses of variance were used to show, among other things, that younger therapists (compared to their older colleagues) rate older patients more negatively in terms of suitability for psychotherapy, the patient's ability to establish a therapeutic working relationship and other parameters. In comparison with their older colleagues, younger therapists perceive themselves as less competent in their relationships with older patients. There are only slight differences with younger patients.


Assuntos
Pacientes , Psicoterapia , Humanos , Psicoterapeutas , Inquéritos e Questionários , Raciocínio Clínico , Relações Profissional-Paciente , Competência Clínica
3.
Z Psychosom Med Psychother ; 70(1): 77-93, 2024 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-38598707

RESUMO

Does the therapeutic style differ in age-homogeneous and age-heterogeneous therapeutic dyads? BACKGROUND AND AIMS: Differences between age-homogeneous and age-heterogeneous therapeutic dyads have rarely been the subject of research.The present study aimed to investigate differences in therapeutic style (Healing and Stressful Involvement). METHOD: A sample of 527 questionnaires completed by therapists of different ages was available. Therapy style was compared between two patient groups (under 40 and over 65 years old) and three therapist groups (25-39, 40-59, ≥ 60). RESULTS: The results show in particular more stress experienced by younger therapists in the treatment of older patients, while older therapists report less stress.There were no or fewer differences in the treatment of younger patients.The regression-analytical results show that the experience of stress in the therapy of older people is associated with a greater fear of old age. CONCLUSION: Finally, some conclusions are discussed with regard to training and supervision of therapists in the treatment of older people.


Assuntos
Medo , Psicoterapia , Humanos , Idoso , Psicoterapia/métodos , Inquéritos e Questionários , Relações Profissional-Paciente
4.
Phys Rev Lett ; 131(16): 160401, 2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37925713

RESUMO

For the efficient simulation of open quantum systems, we often use quantum jump trajectories given by pure states that evolve stochastically to unravel the dynamics of the underlying master equation. In the Markovian regime, when the dynamics is described by a Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation, this procedure is known as Monte Carlo wave function approach. However, beyond ultraweak system-bath coupling, the dynamics of the system is not described by an equation of GKSL type, but rather by the Redfield equation, which can be brought into pseudo-Lindblad form. Here, negative dissipation strengths prohibit the conventional approach. To overcome this problem, we propose a pseudo-Lindblad quantum trajectory (PLQT) unraveling. It does not require an effective extension of the state space, like other approaches, except for the addition of a single classical bit. We test the PLQT for the eternal non-Markovian master equation for a single qubit and an interacting Fermi-Hubbard chain coupled to a thermal bath and discuss its computational effort compared to solving the full master equation.

5.
Phys Rev Lett ; 129(20): 200403, 2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36461992

RESUMO

We put forth a new class of quantum master equations that correctly reproduce the asymptotic state of an open quantum system beyond the infinitesimally weak system-bath coupling limit. Our method is based on incorporating the knowledge of the reduced steady state into its dynamics. The correction not only steers the reduced system toward a correct steady state but also improves the accuracy of the dynamics, thereby refining the archetypal Born-Markov weak-coupling second-order master equations. In case of equilibrium, we use the exact mean-force Gibbs state to correct the Redfield quantum master equation. By benchmarking it with the exact solution of the damped harmonic oscillator, we show that our method also helps correct the long-standing issue of positivity violation, albeit without complete positivity. Our method of a canonically consistent quantum master equation opens a new perspective in the theory of open quantum systems leading to a reduced density matrix accurate beyond the commonly used Redfield and Lindblad equations, while retaining the same conceptual and numerical complexity.

6.
Chembiochem ; 21(9): 1285-1287, 2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32027064

RESUMO

Conjugation of proteins to AMP (AMPylation) is a prevalent post-translational modification (PTM) in human cells, involved in the regulation of unfolded protein response and neural development. Here we present a tailored pronucleotide probe suitable for in situ imaging and chemical proteomics profiling of AMPylated proteins. Using straightforward strain-promoted azide-alkyne click chemistry, the probe provides stable fluorescence labelling in living cells.


Assuntos
Monofosfato de Adenosina/química , Processamento de Proteína Pós-Traducional , Proteínas/química , Proteoma/metabolismo , Alcinos/química , Azidas/química , Química Click , Fluorescência , Células HeLa , Humanos , Imagem Molecular , Proteínas/metabolismo , Proteoma/análise
7.
Biospektrum (Heidelb) ; 26(7): 743-746, 2020.
Artigo em Alemão | MEDLINE | ID: mdl-33250577

RESUMO

Protein AMPylation is a prevalent protein post-translational modification in human cells involved in endoplasmic reticulum stress regulation and neural development. In this article we describe the design, synthesis and application of a pronucleotide probe suitable for in situ fluorescence imaging and chemical protemics profiling of AMPylated proteins. Our probe utilizes straightforward strain-promoted azidealkyne click reaction for fluorescence labeling in living cells.

8.
Proc Natl Acad Sci U S A ; 113(32): 8927-32, 2016 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-27412863

RESUMO

General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative-convective equilibrium simulations, we show that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction. When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation.

9.
Nat Prod Rep ; 34(4): 343-360, 2017 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-28271107

RESUMO

Covering up to September 2016This review reports on natural compounds that derive from the isoxazolinone ring as well as the 3-nitropropanoic acid (3-NPA) moiety. These structural elements occur in compounds that have been identified in plants, insects, bacteria and fungi. In particular, plants belonging to the family of legumes produce such compounds. In the case of insects, isoxazolin-5-one and 3-NPA derivatives were found in leaf beetles of the subtribe Chrysomelina. A number of these natural products have been synthesized so far. In the case of the single compound 3-NPA, several synthetic strategies have been reported and some of the most efficient routes are reviewed. The toxicity of 3-NPA results from its ability to bind covalently to the catalytic center of succinate dehydrogenase causing irreversible inhibition of mitochondrial respiration. As a motif that is produced by many species of plants, leaf beetles and fungi, different detoxification mechanisms for 3-NPA have evolved in different species. These mechanisms are based on amide formation of 3-NPA with amino acids, reduction to ß-alanine, ester formation or oxidation to malonic acid semialdehyde. The biosynthetic pathways of 3-NPA and isoxazolin-5-one moieties have been studied in fungi, plants and leaf beetles. In the case of fungi, 3-NPA derives from aspartate, while leaf beetles use essential amino acids such as valine as ultimate precursors. In the case of plants, it is supposed that malonate serves as a precursor of 3-NPA, as indicated by feeding of 14C-labeled precursors to Indigofera spicata. In other leguminous plants it is suggested that asparagine is incorporated into compounds that derive from isoxazolin-5-one, which was indicated by 14C-labeled compounds as well. In the case of leaf beetles it was demonstrated that detection of radioactivity after 14C-labeling from a few precursors is not sufficient to unravel biosynthetic pathways.


Assuntos
Produtos Biológicos/química , Isoxazóis/química , Nitrocompostos/química , Propionatos/química , Animais , Produtos Biológicos/isolamento & purificação , Isoxazóis/isolamento & purificação , Estrutura Molecular , Nitrocompostos/isolamento & purificação , Propionatos/isolamento & purificação
10.
Org Biomol Chem ; 14(26): 6274-80, 2016 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-27272952

RESUMO

Stable-isotope-labeled precursors were used to establish the biosynthetic pathway leading from ß-alanine towards isoxazolin-5-one glucoside 1 and its 3-nitropropanoate (3-NPA) ester 2 in Chrysomelina larvae. Both structural elements originate from sequestered plant-derived ß-alanine or from propanoyl-CoA that is derived from the degradation of some essential amino acids, e.g. valine. ß-Alanine is converted into 3-NPA and isoxazolinone 5 by consecutive oxidations of the amino group of ß-Ala. Substituting the diphospho group of α-UDP-glucose with 5 generates the isoxazolin-5-one glucoside 1, which serves in the circulating hemolymph of the larva as a platform for esterification with 3-nitropropanoyl-CoA. The pathway was validated with larvae of Phaedon cochleariae, Chrysomela populi as well as Gastrophysa viridula.


Assuntos
Besouros/metabolismo , Glucosídeos/metabolismo , Isoxazóis/metabolismo , Nitrocompostos/metabolismo , Propionatos/metabolismo , Animais , Besouros/química , Glucosídeos/química , Isoxazóis/química , Conformação Molecular , Nitrocompostos/química , Propionatos/química
11.
J Chem Ecol ; 42(3): 240-8, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27033853

RESUMO

Juveniles of the leaf beetles in subtribe Chrysomelina have efficient defense strategies against predators. When disturbed, they transiently expose volatile deterrents in large droplets from nine pairs of defensive glands on their back. Here, we report on an additional line of defense consisting of the non-volatile isoxazolin-5-one glucoside and its 3-nitropropanoyl ester in the larval hemolymph. Because isoxazolin-5-one derivatives were not detectable in related leaf beetle taxa, they serve as a diagnostic marker for the Chrysomelina subtribe. Conjugation of isotopically labelled 3-nitropropionic acid to isoxazolin-5-one glucoside in vivo demonstrates its function as a carrier for the 3-nitropropanoyl esters. The previous identification of characteristic glucosides as precursors of the volatile deterrents underlines the general importance of glucosides for sequestration from food plants, and the subsequent transport in the hemolymph to the defense system. The combination of repellent volatiles with non-volatile toxic compounds in the hemolymph has the potential to create synergistic effects since the odorant stimulus may help predators learn to avoid some foods. The combination of the two defense lines has the advantage, that the hemolymph toxins provide reliable and durable protection, while the repellents may vary after a host plant change.


Assuntos
Besouros/fisiologia , Hemolinfa/metabolismo , Nitrocompostos/metabolismo , Propionatos/metabolismo , Animais , Besouros/metabolismo , Ésteres , Filogenia , Comportamento Predatório
12.
Chemistry ; 21(44): 15554-63, 2015 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-26394612

RESUMO

We report a combined spectroscopical-theoretical investigation on the photosensitization of transition metal nitrosyl complexes. For this purpose, ruthenium nitrosyl complexes based on tetradentate biscarboxamide ligands were synthesized. A crystal structure analysis of a lithium-based ligand intermediate is described. The Ru complexes have been characterized regarding their photophysical and nitric oxide (NO) releasing properties. Quantum chemical calculations have been performed to unravel the influence of the biscarboxamide ligand frame with respect to the molecular electronic properties of the NO-releasing pathway. A quantitative measure for the ligand design within photosensitized Ru complexes is introduced and evaluated spectroscopically and theoretically by using time-dependent density functional theory.

13.
Org Biomol Chem ; 13(13): 4025-30, 2015 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-25723136

RESUMO

A novel procedure for the synthesis of isoxazolin-5-one glycosides starting from unprotected carbohydrates is described. The substrate scope of the one-pot synthetic protocol was explored using D-configured glucose, xylose, maltose, fructose, ribose and 2-deoxyribose. Naturally occurring 2-(ß-D-glucopyranosyl)-3-isoxazolin-5-one and four novel isoxazolin-5-one glycosides derived from xylose, maltose and fructose were synthesized and purified by flash chromatography. The compounds were characterized in terms of chemical structure, photophysical properties as well as pH stability. The photohydrolysis rates of the synthesized glycosides were compared with uridine as a standard to determine the quantum yields for the photoreactions in water.


Assuntos
Glicosídeos/química , Glicosídeos/síntese química , Isoxazóis/química , Luz , Técnicas de Química Sintética , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio
14.
Intensive Crit Care Nurs ; 84: 103748, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38875775

RESUMO

OBJECTIVE: We tested the feasibility of a randomized controlled trial for comparing primary nursing with standard care. RESEARCH METHODOLOGY: Elective cardiac surgical patients were eligible for inclusion. Patients with an intensive care unit stay of ≥ 3 days were followed up until intensive care unit discharge. Recruitment period was one year. SETTING: Two intensive care units at a university hospital specialized in cardiovascular and diabetic diseases. MAIN OUTCOME MEASURES: Primary outcomes were recruitment and delivery rate. Primary clinical outcome was duration of delirium, as assessed by the Confusion Assessment Method for Intensive Care Units. Secondary outcomes included the incidence of delirium, anxiety (10-point Numeric Rating Scale), and the satisfaction of patient relatives (validated questionnaire). RESULTS: Of 369 patients screened, 269 could be allocated to primary nursing (n = 134) or standard care (n = 135), of whom 46 patients and 48 patients, respectively, underwent an intensive care unit stay ≥ 3 days. Thus, recruitment and delivery rates were 73 and 26 %, respectively. During primary nursing and standard care, 18 and 24 patients developed a delirium, with a median duration of 32 (IQR: 14-96) and 24 (IQR: 8-44) hours (P = 0.10). The risk difference of delirium for primary nursing versus standard care was 11 % and the relative risk was 0.65 (95 % CI: 0.28-1.46; P = 0.29). The extent of anxiety was similar between groups (P = 0.13). Satisfaction could be assessed in 73.5 % of relatives, without substantial differences between groups. CONCLUSION: Data demonstrate that a trial for comparing primary nursing with standard care is generally feasible. However, the incidence of delirium may be a better primary outcome parameter than delirium duration, both in terms of long-term patient outcome and robustness of data quality. IMPLICATIONS FOR CLINICAL PRACTICE: A randomized clinical trial regarding nursing organization during intensive care unit stay requires detailed planning of patient recruitment, data evaluation, and power calculation.

15.
Circulation ; 126(11 Suppl 1): S176-82, 2012 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-22965980

RESUMO

BACKGROUND: This study aimed to assess if clampless off-pump coronary artery bypass grafting (CABG) decreases risk-adjusted mortality, stroke rate, and morbidity in unselected patients in comparison to conventional CABG. METHODS AND RESULTS: Between July 2009 and November 2010, data of 1282 consecutive patients undergoing isolated CABG were prospectively recorded. In 30.8% (n=395), clampless off-pump revascularization was used, either with the PAS-Port automated central venous anastomosis system (n=310) or as total arterial revascularization without central anastomoses (n=85). Propensity score (PS) matching was performed based on 15 preoperative risk variables to correct for selection bias. In-hospital mortality and stroke rate as primary end point, as well as major complications and follow-up outcome of clampless off-pump (lessOPCAB) and conventional CABG (cCABG) were compared in 394 matched patient pairs (total: 788 patients). The clampless off-pump technique decreased the in-hospital rate of death (odds ratio, 0.25; 95% confidence interval, 0.05-1.18, P=0.080) and stroke (odds ratio, 0.36; 95% confidence interval, 0.13-0.99, P=0.048) significantly. Complications such as low cardiac output syndrome, prolonged ventilation and rethoracotomy were also reduced by lessOPCAB. Over a 2-year follow-up period overall survival, cerebrovascular and major adverse event rate were significantly lower in the lessOPCAB group, while the repeat revascularization rate was comparable. CONCLUSIONS: In a retrospective PS-matched analysis, clampless off-pump CABG lowers mortality, stroke rate and other morbidity in an unselected group of patients with coronary artery disease.


Assuntos
Ponte de Artéria Coronária sem Circulação Extracorpórea/métodos , Índice de Gravidade de Doença , Idoso , Idoso de 80 Anos ou mais , Anastomose Cirúrgica/métodos , Constrição , Ponte de Artéria Coronária/estatística & dados numéricos , Ponte de Artéria Coronária sem Circulação Extracorpórea/estatística & dados numéricos , Embolia/epidemiologia , Embolia/etiologia , Feminino , Seguimentos , Mortalidade Hospitalar , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/mortalidade , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Risco , Viés de Seleção , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia , Resultado do Tratamento
16.
J Org Chem ; 78(24): 12779-83, 2013 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-24266449

RESUMO

A novel synthetic route was developed for the construction of isoxazolin-5-one glucosides using a cascade reaction. An X-ray crystal structure analysis of a isoxazolin-5-one glucoside confirmed the structure and stereochemistry of the heterocycle. The properties of the α- and ß-anomers of the isoxazolin-5-one glucosides were compared. The first synthesis of 2-[6'-(3″-nitropropanoyl)-ß-D-glucopyranosyl]-3-isoxazolin-5-one was realized by direct enzymatic esterification without need of further protective groups.


Assuntos
Glucosídeos/síntese química , Isoxazóis/síntese química , Cristalografia por Raios X , Glucosídeos/química , Isoxazóis/química , Modelos Moleculares , Conformação Molecular
17.
Chemosphere ; 338: 139534, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37467858

RESUMO

Gadolinium-based contrast agents (GBCAs) are found increasingly in different water bodies, making the investigation of their uptake and distribution behavior in plants a matter of high interest to assess their potential effects on the environment. Depending on the used complexing agent, they are classified into linear or macrocyclic GBCAs, with macrocyclic complexes being more stable. In this study, by using TbCl3, Gd-DTPA-BMA, and Eu-DOTA as model compounds for ionic, linear, and macrocyclic lanthanide species, the elemental species-dependent uptake into leaves of Arabidopsis thaliana under identical biological conditions was studied. After growing for 14 days on medium containing the lanthanide species, the uptake of all studied compounds was confirmed by means of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Furthermore, the uptake rate of TbCl3 and the linear Gd-DTPA-BMA was similar, with Tb and Gd hotspots colocated in the areas of hydathodes and the trichomes of the leaves. In contrast, in the case of the macrocyclic Eu-DOTA, Eu was mainly located in the leaf veins. Additionally, Eu was colocated with Tb and Gd in the hydathode at the tip of the leave. Removal of the lanthanide species from the medium led to a decrease in signal intensities, indicating their subsequent release to some extent. However, seven days after the removal, depositions of Eu, Gd, and Tb were still present in the same areas of the leaves as before, showing that complete elimination was not achieved after this period of time. Overall, more Eu was present in the leaves compared to Gd and Tb, which can be explained by the high stability of the Eu-DOTA complex, potentially leading to a higher transport rate into the leaves, whereas TbCl3 and Gd-DTPA-BMA could interact with the roots, reducing their mobility.


Assuntos
Arabidopsis , Elementos da Série dos Lantanídeos , Terapia a Laser , Compostos Organometálicos , Compostos Organometálicos/química , Gadolínio , Gadolínio DTPA/química , Meios de Contraste/química
18.
Artigo em Alemão | MEDLINE | ID: mdl-22957395

RESUMO

The capacity of affect regulation develops with priority in reciprocal, non-verbal communication processes between the early caregiver and the baby. In this process, the projective identification plays the role of crucial means of communication. Processes of projective identification which emerge in therapeutic and educational interactions can be understood as such an early form of communication which contributes to the afterward-ripening of the capacity of affect regulation. Before the background of recent neuro-psychological findings it becomes clear, why the reciprocal and non-verbal communication between the early caregiver and infant as well as between the therapist and the patient is of such fundamental importance for the structural (re-) maturation of the right cerebral hemisphere, as well as for the connections between the left and right hemisphere. In case the projective identification persists as a defensive strategy in dealing with other people, pathological interaction circles can develop which can be overcome only when, for example, the other person assumes the role of the "regulating other".


Assuntos
Afeto/fisiologia , Cérebro/fisiologia , Identificação Psicológica , Controle Interno-Externo , Relações Interpessoais , Projeção , Adolescente , Adulto , Criança , Pré-Escolar , Comunicação , Humanos , Lactente , Masculino , Relações Mãe-Filho , Apego ao Objeto , Relações Médico-Paciente , Terapia Psicanalítica , Teoria da Mente
19.
J Mass Spectrom ; 57(3): e4812, 2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35156258

RESUMO

The identification and quantification of modified peptides are critical for the functional characterization of post-translational protein modifications (PTMs) to elucidate their biological function. Nowadays, quantitative mass spectrometry coupled with various bioinformatic pipelines has been successfully used for the determination of a wide range of PTMs. However, direct characterization of low abundant protein PTMs in bottom-up proteomic workflow remains challenging. Here, we present the synthesis and evaluation of tandem mass spectrometry tags (TMT) which are introduced via click-chemistry into peptides bearing alkyne handles. The fragmentation properties of the two mass tags were validated and used for screening in a model system and analysis of AMPylated proteins. The presented tags provide a valuable tool for diagnostic peak generation to increase confidence in the identification of modified peptides and potentially for direct peptide-PTM quantification from various experimental conditions.

20.
Insect Sci ; 29(2): 453-466, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34235855

RESUMO

Chrysomelina beetlesstore 3-nitropropionic acid in form of a pretoxin, isoxazolin-5-one glucoside-conjugated ester, to protect themselves against predators. Here we identified a cytochrome P450 monooxygenase, CYP347W1, to be involved in the production of the 3-nitropropionic acid moiety of the isoxazolin-5-one glucoside ester. Knocking down CYP347W1 led to a significant depletion in the concentration of the isoxazolin-5-one glucoside ester and an increase in the concentration of the isoxazolin-5-one glucoside in the larval hemolymph. Enzyme assays with the heterologously expressed CYP347W1 showed free ß-alanine was not the direct substrate. Homology modeling indicated that ß-alanine-CoA ester can fit into CYP347W1's active site. Furthermore, we proved that Phaedon cochleariae eggs are not able to de novo synthesize 3-NPA, although both isoxazolin-5-one glucoside and its 3-NPA-conjugated ester are present in the eggs. These results provide direct evidence for the involvement of CYP347W1 in the biosynthesis of a P. cochleariae chemical defense compound.


Assuntos
Besouros , Mostardeira , Animais , Besouros/química , Neurotoxinas/toxicidade , Nitrocompostos/farmacologia , Propionatos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA