ROS-Suppression Nanoplatform Combined Activation of STAT3/Bcl-2 Pathway for Preventing Myocardial Infarction in Mice.

Myocardial infarction (MI) is the leading cause of death worldwide. The most effective way to treat myocardial infarction is to rescue ischemic cardiomyocytes. After an ischemic event, the overproduction of reactive oxygen species (ROS) is a key driver of myocardial injury. The produced ROS affects mitochondrial function and induces apoptosis in cardiomyocytes. This was accomplished by constructing platelet-membrane-encapsulated ROS-responsive drug-releasing nanoparticles (PMN@NIC-MalNPs) to deliver malonate and niclosamide (NIC). The results revealed that PMN@NIC-MalNPs degraded and released malonate and niclosamide in a high-level ROS microenvironment, effectively reducing the oxidative stress and apoptosis rate. By enhancing basal mitochondrial oxygen consumption rate (OCR), adenosine triphosphate (ATP) production, and spare respiratory capacity (SRC) in vitro, reduced the oxidative stress levels and restored mitochondrial function. In vivo studies revealed that the PMN@NIC-MalNPs improved cardiac dysfunction, inhibited succinate dehydrogenase (SDH) activity, increased ATP production, and reduced the myocardial infarct size in myocardial infarction model mice. Further, transcriptome analysis and Western blot revealed that PMN@NIC-MalNPs prevented apoptosis by activating the expressions of the signal transducer and activator of transcription 3 (STAT3) and Bcl-2, and inhibiting the expression of Bax. Thus, this study provides a novel therapeutic solution for treating myocardial infarction and predicting the viability of an antioxidant and antiapoptotic therapeutic solution in the treatment of myocardial injury.

Synthesis, Characterization, and Bioactivity of the Lichen Pigments Pulvinamide, Rhizocarpic Acid, and Epanorin and Congeners.

The lichen natural products pulvinamide, rhizocarpic acid, and epanorin have been synthesized and characterized spectroscopically and by X-ray crystallography. The syntheses, by ring-opening of pulvinic acid dilactone (PAD), may well be biomimetic, given the well-known occurrence of PAD in lichen. The enantiomers, ent-rhizocarpic acid and ent-epanorin, and corresponding carboxylic acids, norrhizocarpic acid and norepanorin, were similarly prepared. All compounds were assessed for growth inhibitory activity against selected bacteria, fungi, a protist, a mammalian tumor cell line, and normal cells. Rhizocarpic acid is weakly antibacterial (Bacillus subtilis MIC = 50 µg/mL) and possesses modest but selective antitumor activity (NS-1 murine myeloma MIC = 3.1 µg/mL) with >10-fold potency relative to its enantiomer (MIC = 50 µg/mL).

Post-Translational Formation of Aminomalonate by a Promiscuous Peptide-Modifying Radical SAM Enzyme.

Aminomalonate (Ama) is a widespread structural motif in Nature, whereas its biosynthetic route is only partially understood. In this study, we show that a radical S-adenosylmethionine (rSAM) enzyme involved in cyclophane biosynthesis exhibits remarkable catalytic promiscuity. This enzyme, named three-residue cyclophane forming enzyme (3-CyFE), mainly produces cyclophane in vivo, whereas it produces formylglycine (FGly) as a major product and barely produce cyclophane in vitro. Importantly, the enzyme can further oxidize FGly to produce Ama. Bioinformatic study revealed that 3-CyFEs have evolved from a common ancestor with anaerobic sulfatase maturases (anSMEs), and possess a similar set of catalytic residues with anSMEs. Remarkably, the enzyme does not need leader peptide for activity and is fully active on a truncated peptide containing only 5 amino acids of the core sequence. Our work discloses the first ribosomal path towards Ama formation, providing a possible hint for the rich occurrence of Ama in Nature.

Identification of the rhizospheric microbe and metabolites that led by the continuous cropping of ramie (Boehmeria nivea L. Gaud).

Continuous cropping lowers the production and quality of ramie (Boehmeria nivea L. Gaud). This study aimed to reveal the metagenomic and metabolomic changes between the healthy- and obstacle-plant after a long period of continuous cropping. After 10 years of continuous cropping, ramie planted in some portions of the land exhibited weak growth and low yield (Obstacle-group), whereas, ramie planted in the other portion of the land grew healthy (Health-group). We collected rhizosphere soil and root samples from which measurements of soil chemical and plant physiochemical properties were taken. All samples were subjected to non-targeted gas chromatograph-mass spectrometer (GS/MS) metabolome analysis. Further, metagenomics was performed to analyze the functional genes in rhizospheric soil organisms. Based on the findings, ramie in Obstacle-group were characterized by shorter plant height, smaller stem diameter, and lower fiber production than that in Health-group. Besides, the Obstacle-group showed a lower relative abundance of Rhizobiaceae, Lysobacter antibioticus, and Bradyrhizobium japonicum, but a higher relative abundance of Azospirillum lipoferum and A. brasilense compared to the Health-group. Metabolomic analysis results implicated cysteinylglycine (Cys-Gly), uracil, malonate, and glycerol as the key differential metabolites between the Health- and Obstacle-group. Notably, this work revealed that bacteria such as Rhizobia potentially synthesize IAA and are likely to reduce the biotic stress of ramie. L. antibioticus also exerts a positive effect on plants in the fight against biotic stress and is mediated by metabolites including orthophosphate, uracil, and Cys-Gly, which may serve as markers for disease risk. These bacterial effects can play a key role in plant resistance to biotic stress via metabolic and methionine metabolism pathways.

Identification of histone malonylation in the human fetal brain and implications for diabetes-induced neural tube defects.

BACKGROUND: Neural tube defects (NTDs) are severe congenital malformations. Diabetes during pregnancy is a risk factor for NTDs, but its mechanism remains elusive. Emerging evidence suggests that protein malonylation is involved in diabetes. Here, we report the correlation between histone lysine malonylation in diabetes-induced NTDs. METHODS: Nano-HPLC/MS/MS was used to screen the histone malonylation profile in human embryonic brain tissue. Then, the histone malonylation level was compared between the brains of normal control mice and mice with diabetes-induced NTDs. Finally, the histone malonylation level was compared under high glucose exposure in an E9 neuroepithelial cell line (NE4C). RESULTS: A total of 30 histone malonylation sites were identified in human embryonic brain tissue, including 18 novel sites. Furthermore, we found an increased histone malonylation level in brain tissues from mice with diabetes-induced NTDs. Finally, both the histone malonylation modified sites and the modified levels were proved to be increased in the NE4C treated with high glucose. CONCLUSION: Our results present a comprehensive map of histone malonylation in the human fetal brain. Furthermore, we provide experimental evidence supporting a relationship between histone malonylation and NTDs caused by high glucose-induced diabetes. These findings offer new insights into the pathological role of histone modifications in human NTDs.

Lysine malonylation and propionylation are prevalent in human lens proteins.

Acylated lysine residues represent major chemical modifications in proteins. We investigated the malonylation and propionylation of lysine residues (MalK, PropK) in the proteins of aging human lenses. Western blot results showed that the two modifications are present in human lens proteins. Liquid chromatography-mass spectrometry (LC-MS/MS) results showed 4-18 and 4-32 pmol/mg protein of MalK and PropK, respectively, in human lens proteins with no apparent changes related to aging. Mass spectrometry results revealed that MalK- and PropK-modified lysine residues are present in all major crystallins, other cytosolic proteins, and membrane and cytoskeletal proteins of the lens. Several mitochondrial and cytosolic proteins in cultured human lens epithelial cells showed MalK and PropK modifications. Sirtuin 3 (SIRT3) and sirtuin 5 (SIRT5) were present in human lens epithelial and fiber cells. Moreover, lens epithelial cell lysate deacylated propionylated and malonylated lysozyme. The absence of SIRT3 and SIRT5 led to higher PropK and MalK levels in mouse lenses. Together, these data suggest that MalK and PropK are widespread modifications in lens and SIRT3 and SIRT5 could regulate their levels in lens epithelial cells.

Deciphering the binding mode and mechanistic insights of pentadecylidenemalonate (1b) as activator of histone acetyltransferase PCAF.

Histone acetyltransferases (HATs) is one among the conspicuous posttranslational modification in eukaryotic cells. p300/CBP Associated Factor (PCAF) and CREB-binding protein (CBP) are the two highly homologous HAT family which are vastly implicated in several diseases like cancer, diabetes, etc. Pentadecylidenemalonate, a simplified analog of anacardic acid, was reported as first mixed inhibitor/activator of HATs which inhibits p300/CBP and activates PCAF. It was appointed earlier as a valuable biological tool to understand the mechanism of lysine acetyltransferases due to its powerful apoptotic effect. In this study, pentadecylidenemalonate was taken for deciphering the binding mode, key interacting residues as well as mechanistic insights on PCAF and CBP as activator and inhibitor, respectively. This study is highly believed to help in rational design on antineoplastic drugs against PCAF. Communicated by Ramaswamy H. Sarma.

Identification and Quantitation of Malonic Acid Biomarkers of In-Born Error Metabolism by Targeted Metabolomics.

Malonic acid (MA), methylmalonic acid (MMA), and ethylmalonic acid (EMA) metabolites are implicated in various non-cancer disorders that are associated with inborn-error metabolism. In this study, we have slightly modified the published 3-nitrophenylhydrazine (3NPH) derivatization method and applied it to derivatize MA, MMA, and EMA to their hydrazone derivatives, which were amenable for liquid chromatography- mass spectrometry (LC-MS) quantitation. 3NPH was used to derivatize MA, MMA, and EMA, and multiple reaction monitoring (MRM) transitions of the corresponding derivatives were determined by product-ion experiments. Data normalization and absolute quantitation were achieved by using 3NPH derivatized isotopic labeled compounds 13C2-MA, MMA-D3, and EMA-D3. The detection limits were found to be at nanomolar concentrations and a good linearity was achieved from nanomolar to millimolar concentrations. As a proof of concept study, we have investigated the levels of malonic acids in mouse plasma with malonyl-CoA decarboxylase deficiency (MCD-D), and we have successfully applied 3NPH method to identify and quantitate all three malonic acids in wild type (WT) and MCD-D plasma with high accuracy. The results of this method were compared with that of underivatized malonic acid standards experiments that were performed using hydrophilic interaction liquid chromatography (HILIC)-MRM. Compared with HILIC method, 3NPH derivatization strategy was found to be very efficient to identify these molecules as it greatly improved the sensitivity, quantitation accuracy, as well as peak shape and resolution. Furthermore, there was no matrix effect in LC-MS analysis and the derivatized metabolites were found to be very stable for longer time. Graphical Abstract ᅟ.

Application of Metabolic Profiling to Abdominal Aortic Aneurysm Research.

Abdominal aortic aneurysm (AAA) is a complex disease posing diagnostic and therapeutic challenges. Metabonomics may aid in the diagnosis of AAA, determination of individualized risk, discovery of therapeutic targets, and improve understanding of pathogenesis. A systematic review of the diversity and outcomes of existing AAA metabonomic research has been performed. Original research studies applying metabonomics to human aneurysmal disease are included. Seven relevant articles were identified: four studies were based on plasma/serum metabolite profiling, and three studies examined aneurysmal tissue. Aminomalonic acid, guanidinosuccinic acid, and glycerol emerge as potential plasma biomarkers of large aneurysm. Lipid profiling improves predictive models of aneurysm presence. Patterns of metabolite variation associated with AAA relate to carbohydrate and lipid metabolism. Perioperative perturbations in metabolites suggest differential systemic inflammatory responses to surgery, generating hypotheses for adjunctive perioperative therapy. Significant limitations include small study sizes, lack of correction for multiple testing false discovery rates, and single time-point sampling. Metabolic profiling carries the potential to identify biomarkers of AAA and elucidate pathways underlying aneurysmal disease. Statistically and methodologically robust studies are required for validation, addressing the hiatus in understanding mechanisms of aneurysm growth and developing effective treatment strategies.

Comparative proteomic and metabolomic analysis of Streptomyces tsukubaensis reveals the metabolic mechanism of FK506 overproduction by feeding soybean oil.

FK506 (tacrolimus) is a 23-membered polyketide macrolide that possesses powerful immunosuppressant activity. In this study, feeding soybean oil into the fermentation culture of Streptomyces tsukubaensis improved FK506 production by 88.8%. To decipher the overproduction mechanism, comparative proteomic and metabolomic analysis was carried out. A total of 72 protein spots with differential expression in the two-dimensional gel electrophoresis (2-DE) were identified by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS), and 66 intracellular metabolites were measured by gas chromatography-mass spectrometer (GC-MS). The analysis of proteome and metabolome indicated that feeding soybean oil as a supplementary carbon source could not only strengthen the FK506 precursor metabolism and energy metabolism but also tune the pathways related to transcriptional regulation, translation, and stress response, suggesting a better intracellular metabolic environment for the synthesis of FK506. Based on these analyses, 20 key metabolites and precursors of FK506 were supplemented into the soybean oil medium. Among them, lysine, citric acid, shikimic acid, and malonic acid performed excellently for promoting the FK506 production and biomass. Especially, the addition of malonic acid achieved the highest FK506 production, which was 1.56-fold of that in soybean oil medium and 3.05-fold of that in initial medium. This report represented the first comprehensive study on the comparative proteomics and metabolomics applied in S. tsukubaensis, and it would be a rational guidance to further strengthen the FK506 production.

Discovery of novel anti-angiogenesis agents. Part 6: Multi-targeted RTK inhibitors.

Angiogenesis is modulated by a multitude of pro-angiogenic factors including VEGFR-2, Tie-2, and EphB4. Moreover, their crosstalk also had been well elaborated. We have identified several diarylurea-based VEGFR-2 inhibitors as potential anti-angiogenesis agents. As a continuation to our previous research, two series of diaryl malonamide and diaryl thiourea derivatives have been developed as multiplex VEGFR-2/Tie-2/EphB4 inhibitors. Interestingly, the biological evaluation indicated that several compounds bearing trifluoromethyl or trifluoromethoxyl exhibited promising multiplex inhibition against angiogenesis-related VEGFR-2, Tie-2, and EphB4. The representative compound (18a) displayed both potent multi-targeted RTK inhibition and considerable antiproliferative activities against human umbilical vein endothelial cells (EA.hy926). These results will contribute to the discovery of novel muti-targeted anti-angiogenesis agents.

Divergent biosynthesis yields a cytotoxic aminomalonate-containing precolibactin.

Colibactin is an as-yet-uncharacterized genotoxic secondary metabolite produced by human gut bacteria. Here we report the biosynthetic discovery of two new precolibactin molecules from Escherichia coli, including precolibactin-886, which uniquely incorporates the highly sought genotoxicity-associated aminomalonate building block into its unprecedented macrocyclic structure. This work provides new insights into the biosynthetic logic and mode of action of this colorectal-cancer-linked microbial chemical.

Composites of malonic acid diamides and phospholipids--Impact of lipoplex stability on transfection efficiency.

The use of cationic lipids as gene delivery systems is a basic method in gene therapy. Through ongoing research, lipofection is currently the leader of non-viral vectors in clinical trials. However, in order to unleash the full potential of lipofection further intensive investigations are indispensable. In this study, various lipoplex formulations were compared regarding their ability to bind DNA. To obtain information about a possible premature release of DNA at the cell surface, heparin and chondroitin dependent lipoplex destabilization experiments were carried out. Complementary investigations in cell culture were performed to quantify DNA outside the cell. Additionally, DNase I stability was investigated. In this regard a multitude of methods, namely confocal laser scanning microscopy (CLSM), polymerase chain reaction (PCR), cell culture experiments, ethidium bromide assay, gel electrophoresis, Langmuir-isotherm experiments, infrared reflection absorption spectroscopy (IRRAS), Brewster angle microscopy (BAM), zeta-(ζ)-potential measurements, and dynamic light scattering (DLS), were applied. Although the complexation of DNA is a fundamental step, we show that the DNA release by biological agents (proteoglycans) and an unsuccessful cell attachment are major transfection limiting parameters.

Regulation of human serine racemase activity and dynamics by halides, ATP and malonate.

D-Serine is a non-proteinogenic amino acid that acts as a co-agonist of the NMDA receptors in the central nervous system. D-Serine is produced by human serine racemase (hSR), a homodimeric pyridoxal 5'-phosphate (PLP)-dependent enzyme that also catalyzes the physiologically relevant ß-elimination of both L- and D-serine to pyruvate and ammonia. After improving the protein purification yield and stability, which had so far limited the biochemical characterization of hSR, we found that the catalytic activity is affected by halides, in the order fluoride > chloride > bromide. On the contrary, iodide elicited a complete inhibition, accompanied by a modulation of the tautomeric equilibrium of the internal aldimine. We also investigated the reciprocal effects of ATP and malonate, an inhibitor that reversibly binds at the active site, 20 Å away from the ATP-binding site. ATP increased ninefold the affinity of hSR for malonate and malonate increased 100-fold that of ATP, confirming an allosteric interaction between the two binding sites. To further investigate this allosteric communication, we probed the active site accessibility by quenching of the coenzyme fluorescence in the absence and presence of ATP. We found that ATP stabilizes a closed conformation of the external aldimine Schiff base, suggesting a possible mechanism for ATP-induced hSR activation.

Biochemical modulation of cell energy by 2-deoxyglucose and malonate in 7,12-dimethylbenz(a)anthracene-induced carcinogenesis in rats.

The goal of this study was to explore the impact of 2-deoxglucose or malonate individually or in combination on the level of cell energy (adenosine-5'-triphosphate) and oxidative stress in 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary proliferation in rats. A total of 60 adult female Sprague Dawley rats were randomly divided into five groups (12 rats each): group I serves as the control group. Rats in groups (II-V) were administrated intragastrically a single dose of 50 mg/kg body weight (bw) of DMBA. A day after DMBA administration, rats in group III were injected intraperitoneally (ip) with 100 mg 2-deoxyglucose (2-DG)/kg bw daily. Rats in group IV were injected ip with 10 mg sodium malonate/kg bw daily. Rats in group V were injected ip with 100 mg 2-DG/kg bw and 10 mg sodium malonate/kg bw (treatment for 90 days). The results obtained showed that DMBA induced oxidative stress by decreasing the activities of glutathione reductase (GRase) and superoxide dismutase (SOD), glutathione peroxidase (GPx) and elevating the levels of malondialdehyde (MDA) and nitric oxide (NO) in mammary tissues when compared with control. The combined treatment protected against the previous deleterious changes by a significant elevation in the activities of GRase and SOD, GPx and lowering the levels of MDA and NO more potentially when compared with individual treatment. Apoptosis, as indicated by a significant release of cytochrome c from mitochondria into the cytosol, observed in DMBA-injected rats was positively significantly correlated with the elevation of the level of NO. These data explained the possible additive effect of 2-DG and malonate by depleting the cell energy by their protective effects against the earlier stages of carcinogenesis.

Mapeamento cruzado: títulos diagnósticos formulados segundo a CIPE® versus diagnósticos da NANDA Internacional / Cross-Mapping: diagnostic labels formulated according to the ICNP® versus diagnosis of NANDA International / Cruz mapeo: etiquetas diagnósticas formuladas de acuerdo con la CIPE® y comparación con los diagnósticos de la NANDA Internacional

Estudo descritivo cujos objetivos foram elaborar títulos diagnósticos de enfermagem segundo a CIPE®, realizar mapeamento cruzado entre as formulações diagnósticas e os títulos diagnósticos da NANDA-I, identificar dentre os títulos diagnósticos formulados os constantes e não constantes na NANDA-I e realizar mapeamento dos títulos formulados com as Necessidades Humanas Básicas. Utilizou-se técnica de oficina, com 32 enfermeiros de unidades de terapia intensiva, de mapeamento cruzado e de validação por concordância com peritos. Na oficina foram elaborados 1.665 títulos diagnósticos submetidos a processo de refinamento que resultou em 120 títulos, submetidos a mapeamento cruzado com títulos diagnósticos da NANDA-I e com as necessidades humanas básicas. Os produtos do mapeamento foram submetidos à validação de conteúdo por dois enfermeiros peritos, obtendo-se índices de concordância de 92% e 100%. Constatou-se que 63 títulos constavam na NANDA-I e 47 não.

This descriptive study aimed at elaborating nursing diagnostic labels according to ICNP®; conducting a cross-mapping between the diagnostic formulations and the diagnostic labels of NANDA-I; identifying the diagnostic labels thus obtained that were also listed in the NANDA-I; and mapping them according to Basic Human Needs. The workshop technique was applied to 32 intensive care nurses, the cross-mapping and validation based on agreement with experts. The workshop produced 1665 diagnostic labels which were further refined into 120 labels. They were then submitted to a cross-mapping process with both NANDA-I diagnostic labels and the Basic Human Needs. The mapping results underwent content validation by two expert nurses leading to concordance rates of 92% and 100%. It was found that 63 labels were listed in NANDA-I and 47 were not.

Estudio descriptivo cuyos objetivos fueron la elaboración de etiquetas de diagnósticos de enfermería según la CIPE®, para llevar a cabo lo mapeo cruzado entre el diagnóstico formulado y las etiquetas de los diagnósticos NANDA-I, para identificar entre los títulos de diagnósticos formulados los que eran constantes y no constantes en NANDA-I y asignarlos a las necesidades humanas básicas. Fueron conducidas técnica de oficina con 32 enfermeros de las unidades de cuidados intensivos, mapeo cruzado y validación de acuerdo con los expertos. Se elaboró 1665 títulos diagnósticos en la oficina sometidos a un proceso de refinamiento. El resultado fue de 120 títulos que se presentaron a un proceso de mapeo con los títulos de diagnósticos de la NANDA-I y con las necesidades humanas básicas. Validación de contenido se realizó con los productos de lo mapeo por dos enfermeras expertas y las tasas de concordancia del 92% y 100% fueron obtenidas. Se encontró que 63 títulos estaban contenidos en la NANDA-I y 47 no lo hicieron.

Burnout syndrome among undergraduate nursing students at a public university / Síndrome de Burnout entre estudantes de graduação em enfermagem de uma universidade pública / Síndrome de Burnout entre estudiantes de pregrado en enfermería de una universidad pública

OBJECTIVE: to investigate the burnout syndrome and its relationship with demographic and academic variables among undergraduate nursing students at a public university in Southern Brazil. METHOD: a quantitative study with 168 students, by applying an adaptation of the Maslach Burnout Inventory - Student Survey, validated for this study. We used descriptive and variance analysis of the data analysis. RESULTS: we found that students do not have the burnout syndrome, manifesting high average scores in Emotional Exhaustion, low in Disbelief and high in Professional Effectiveness; that younger students who perform leisure activities have greater Professional Effectiveness, unlike students in early grades with no extracurricular activities; combining work and studies negatively influenced only the Professional Effectiveness factor, while the intention of giving up influenced negatively Disbelief and Professional Effectiveness factors. CONCLUSION: the situations that lead students to Emotional Exhaustion need to be recognized, considering the specificity of their study environments. .

OBJETIVO: investigar a síndrome de Burnout e sua relação com variáveis sociodemográficas e acadêmicas, entre estudantes de graduação em enfermagem de uma universidade pública do Sul do Brasil. MÉTODO: estudo quantitativo, realizado com 168 estudantes, mediante a aplicação de uma adaptação do Maslach Burnout Inventory - Student Survey, validada para este estudo. Utilizou-se a análise descritiva e de variância para análise dos dados. RESULTADOS: constatou-se que os estudantes não apresentam a síndrome de Burnout, manifestando médias altas em exaustão emocional, baixas em descrença e altas em eficácia profissional; que estudantes mais jovens e que realizam atividades de lazer apresentam maior eficácia profissional, diferentemente de estudantes das séries iniciais e que não realizam atividades extracurriculares; conciliar trabalho e estudos influenciou negativamente apenas o fator eficácia profissional, enquanto a intenção de desistir do curso influenciou negativamente os fatores descrença e eficácia profissional. CONCLUSÃO: faz-se necessário o reconhecimento das situações que levam os estudantes à exaustão emocional, considerando a especificidade de seus ambientes de formação. .

OBJETIVO: investigar la síndrome de burnout y su relación con variables sociodemográficas y académicas, entre estudiantes de pregrado en enfermería de una universidad pública del Sur de Brasil. MÉTODO: estudio cuantitativo, desarrollado con 168 estudiantes, mediante la aplicación de una adaptación del Maslach Burnout Inventory - Student Survey, validada para fines de ese estudio. Fueron utilizados los análisis descriptivo y de variancia para analizar los datos. RESULTADOS: se constató que los estudiantes no presentan la síndrome de burnout, manifestando altos promedios en Agotamiento Emocional, bajos en Descreencia y altos en Eficacia Profesional; que estudiantes más jóvenes y que practican actividades de ocio presentan mayor Eficacia Profesional, diferentemente de estudiantes de los años iniciales sin actividades extracurriculares; conciliar trabajo y estudios influyó negativamente apenas el factor Eficacia Profesional, mientras la intención de desistir del curso influyó negativamente los factores Descreencia y Eficacia Profesional. CONCLUSIÓN: es necesario reconocer las situaciones que llevan a los estudiantes al Agotamiento Emocional, considerando la especificidad de sus ambientes de formación. .

Glycosylation and subsequent malonylation of isoflavonoids in E. coli: strain development, production and insights into future metabolic perspectives.

Genistin and daidzein exhibit a protective effect on DNA damage and inhibit cell proliferation. Glycosylation and malonylation of the compounds increase water solubility and stability. Constructed pET15b-GmIF7GT and pET28a-GmIF7MAT were used for the transformation of Escherichia coli and bioconversion of genistein and daidzein. To increase the availability of malonyl-CoA, a critical precursor of GmIF7MAT, genes for the acyl-CoA carboxylase α and ß subunits (nfa9890 and nfa9940), biotin ligase (nfa9950), and acetyl-CoA synthetase (nfa3550) from Nocardia farcinia were also introduced. Thus, the isoflavonoids were glycosylated at position 7 by 7-O-glycosyltranferase and were further malonylated at position 6(″) of glucose by malonyl-CoA: isoflavone 7-O-glucoside-6(″)-O-malonyltransferase both from Glycine max. Engineered E. coli produced 175.7 µM (75.90 mg/L) of genistin and 14.2 µM (7.37 mg/L) genistin 6''-O-malonate. Similar conditions produced 162.2 µM (67.65 mg/L) daidzin and 12.4 µM (6.23 mg/L) daidzin 6''-O-malonate when 200 µM of each substrate was supplemented in the culture. Based on our findings, we speculate that isoflavonoids and their glycosides may prove useful as anticancer drugs with added advantage of increased solubility, stability and bioavailability.

[Estimation of ATP-dependent K(+)-channel contribution to potential-dependent potassium uptake in the rat brain mitochondria].

The effect of potassium on state 4 respiration (substrate oxidation in the absence of ADP) was investigated. It was shown that potential-dependent potassium uptake in the brain mitochondria results in mitochondrial depolarization. Taking into account depolarization effect of potassium, the contribution of the endogenous proton leak as well as K(+)-uptake to the respiration rate was calculated. It was shown that such estimation allows the share of ATP-dependent potassium channel contribution to potential-dependent potassium uptake to be determined by polarographic method.

Changes on organic acid secretion and accumulation in Plantago almogravensis Franco and Plantago algarbiensis Samp. under aluminum stress.

We investigated the effect of Al (400µM) on organic acids secretion, accumulation and metabolism in Plantago almogravensis Franco and Plantago algarbiensis Samp. Al induced a significant reduction on root elongation only in P. algarbiensis. Both species accumulated considerable amounts of Al (>120µgg(-1)) in their tissues, roots exhibiting the highest contents (>900µgg(-1)). Al stimulated malonic acid secretion in P. algarbiensis, while citric, succinic and malic acids were secreted by P. almogravensis. Moreover, Al uptake was accompanied by substantial increases of citric, oxalic, malonic and fumaric acids contents in the plantlets of either species. Overall, the acid metabolizing enzymes were not directly involved in the Al induced organic acid secretion and accumulation. Our data suggest that Al detoxification in P. almogravensis implies both secretion of organic acids from roots and tolerance to high Al tissue concentrations, while in P. algarbiensis only the tolerance mechanism seems to be involved.