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2.
Artículo en Inglés | MEDLINE | ID: mdl-38622015

RESUMEN

Complex behaviors are mediated by a diverse class of neurons and glia produced during development. Both neural stem cell-intrinsic and -extrinsic temporal cues regulate the appropriate number, molecular identity, and circuit assembly of neurons. The Drosophila central complex (CX) is a higher-order brain structure regulating various behaviors, including sensory-motor integration, celestial navigation, and sleep. Most neurons and glia in the adult CX are formed during larval development by 16 Type II neural stem cells (NSCs). Unlike Type I NSCs, which directly give rise to the ganglion mother cells (GMCs), Type II NSCs give rise to multiple intermediate neural progenitors (INPs), and each INP in turn generates multiple GMCs, hence fostering the generation of longer and more diverse lineages. This makes Type II NSCs a suitable model to unravel the molecular mechanisms regulating neural diversity in more complex lineages. In this review, we elaborate on the classification and identification of NSCs based on the types of division adopted and the molecular markers expressed in each type. In the end, we discuss genetic methods for lineage analysis and birthdating. We also explain the temporal expression of stem cell factors and genetic techniques to study how stem cell factors may regulate neural fate specification.

3.
Artículo en Inglés | MEDLINE | ID: mdl-38622016

RESUMEN

From insects to humans, the nervous system generates complex behaviors mediated by distinct neural circuits that are composed of diverse cell types. During development, the spatiotemporal gene expression of the neural progenitors expands the diversity of neuronal and glial subtypes. Various neural stem cell-intrinsic and -extrinsic gene programs have been identified that are thought to play a major role in generating diverse neuronal and glial cell types. Drosophila has served as an excellent model system for discovering the fundamental principles of nervous system development and function. The sophisticated genetic tools allow us to link the origin and birth timing (the time when a particular neuron is born during development) of neuron types to unique neural stem cells (NSCs) and to a developmental time. In Drosophila, a special class of NSCs called Type II NSCs has adopted a more advanced division mode to generate lineages for the higher-order brain center, the central complex, which is an evolutionarily conserved brain region found in all insects. Type II NSCs, similar to the human outer radial glia, generate intermediate neural progenitors (INPs), which divide many times to produce about eight to 10 progeny. Both Type II NSCs and INPs express distinct transcription factors and RNA-binding proteins that have been proposed to regulate the specification of cell types populating the adult central complex. Here, we describe the recently invented lineage filtering system, called cell class-lineage intersection (CLIn), which enables the tracking and birthdating of the Type II NSC lineages. Using CLIn, one can easily generate clones of different Type II NSCs and identify not only the origins of neurons of interest but also their birth time.

4.
Artículo en Inglés | MEDLINE | ID: mdl-38604531

RESUMEN

BACKGROUND: Patient-reported outcome measures (PROMs) are validated and standardized tools that complement physician evaluations and guide treatment decisions. PROMs are crucial for monitoring atopic dermatitis (AD) and chronic urticaria (CU) in clinical practice, but there are unmet needs and knowledge gaps regarding their use in clinical practice. OBJECTIVE: We investigated the global real-world use of AD and CU PROMs in allergology and dermatology clinics as well as their associated local and regional networks. METHODS: Across 72 specialized allergy and dermatology centers and their local and regional networks, 2,534 physicians in 73 countries completed a 53-item questionnaire on the use of PROMs for AD and CU. RESULTS: Of 2,534 physicians, 1,308 were aware of PROMs. Of these, 14% and 15% used PROMs for AD and CU, respectively. Half of physicians who use PROMs do so only "rarely" or "sometimes". AD and CU PROM usage is associated with being female, younger, and a dermatologist. POSCORAD and UAS were the most utilized PROMs for AD and CU, respectively. Monitoring disease control and activity are the main drivers of the use of PROMs. Time constraints were the primary obstacle to using PROMs, followed by the impression that patients dislike PROMs. AD and CU PROM users would like training in selecting the proper PROM. CONCLUSION: Even though PROMs offer several benefits, their use in routine practice is suboptimal, and physicians perceive barriers to their use. It is essential to attain higher levels of PROM implementation in accordance with national and international standards.

5.
Curr Microbiol ; 80(8): 256, 2023 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-37357232

RESUMEN

Different strategies were tested to reduce biofilm formation of the model marine bacteria Cobetia marina and Marinobacter hydrocarbonoclasticus on cross-linked polydimethylsiloxane (PDMS) coated aluminum and cellulose acetate surfaces modified by addition of multi-walled carbon nanotubes (MWCNT) or exposure of the surfaces to bromine vapors in the presence and absence of UV irradiation. The three surface modifications explored led to important reductions in biofilm formation for the two marine bacteria, up to 30% in the case of exposure to Br2(g). Biofouling reduction could be correlated to surface properties in all cases through the introduction of a quantitative theoretical model based on an effective roughness parameter, Raeff, that accounted for the different morphological changes observed. The model considers the possibility of bacterial inclusion into large surface wells, as observed by AFM in the case of Br2(g) + UV light treatment. In addition, a linear relationship was observed between biofouling reduction and the Raeff effective roughness parameter.


Asunto(s)
Incrustaciones Biológicas , Nanotubos de Carbono , Biopelículas , Dimetilpolisiloxanos , Bacterias
6.
Sci Rep ; 13(1): 7131, 2023 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-37130962

RESUMEN

Parageobacillus thermoglucosidasius is a thermophilic bacterium characterized by rapid growth, low nutrient requirements, and amenability to genetic manipulation. These characteristics along with its ability to ferment a broad range of carbohydrates make P. thermoglucosidasius a potential workhorse in whole-cell biocatalysis. The phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) catalyzes the transport and phosphorylation of carbohydrates and sugar derivatives in bacteria, making it important for their physiological characterization. In this study, the role of PTS elements on the catabolism of PTS and non-PTS substrates was investigated for P. thermoglucosidasius DSM 2542. Knockout of the common enzyme I, part of all PTSs, showed that arbutin, cellobiose, fructose, glucose, glycerol, mannitol, mannose, N-acetylglucosamine, N-acetylmuramic acid, sorbitol, salicin, sucrose, and trehalose were PTS-dependent on translocation and coupled to phosphorylation. The role of each putative PTS was investigated and six PTS-deletion variants could not grow on arbutin, mannitol, N-acetylglucosamine, sorbitol, and trehalose as the main carbon source, or showed diminished growth on N-acetylmuramic acid. We concluded that PTS is a pivotal factor in the sugar metabolism of P. thermoglucosidasius and established six PTS variants important for the translocation of specific carbohydrates. This study lays the groundwork for engineering efforts with P. thermoglucosidasius towards efficient utilization of diverse carbon substrates for whole-cell biocatalysis.


Asunto(s)
Acetilglucosamina , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato , Acetilglucosamina/metabolismo , Arbutina , Trehalosa , Fosfotransferasas/genética , Carbohidratos , Bacterias/metabolismo , Manitol , Sorbitol , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo
7.
ACS Sustain Chem Eng ; 10(16): 5078-5083, 2022 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-35493695

RESUMEN

Regioselective glycosylation is a chemical challenge, leading to multistep syntheses with protecting group manipulations, ultimately resulting in poor atom economy and compromised sustainability. Enzymes allow eco-friendly and regioselective bond formation with fully deprotected substrates in a single reaction. For the selective glucosylation of silibinin, a pharmaceutical challenged with low solubility, enzyme engineering has previously been employed, but the resulting yields and k cat were limited, prohibiting the application of the engineered catalyst. Here, we identified a naturally regioselective silibinin glucosyltransferase, UGT706F8, a family 1 glycosyltransferase from Zea mays. It selectively and efficiently (k cat = 2.1 ± 0.1 s-1; K M = 36.9 ± 5.2 µM; TTN = 768 ± 22) catalyzes the quantitative synthesis of silibinin 7-O-ß-d-glucoside. We solved the crystal structure of UGT706F8 and investigated the molecular determinants of regioselective silibinin glucosylation. UGT706F8 was the only regioselective enzyme among 18 glycosyltransferases found to be active on silibinin. We found the temperature optimum of UGT706F8 to be 34 °C and the pH optimum to be 7-8. Our results indicate that UGT706F8 is an efficient silibinin glycosyltransferase that enables biocatalytic production of silbinin 7-O-ß-d-glucoside.

8.
Glob Chang Biol ; 27(18): 4381-4391, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34091988

RESUMEN

The temporal trend of aboveground net primary production (ANPP) is frequently used to estimate the effect of humans on ecosystems. In water-limited ecosystems, like most grazing areas in the world, the effect of humans act upon ANPP in combination with environmental variations. Our main objective was to quantify long-term (1981-2012) changes of ANPP and discriminate the causes of these changes between environmental and human at a subcontinental scale, across vast areas of Patagonia. We estimated ANPP through a radiative model based on remote sensing data. Then, we evaluated the relation between ANPP and environmental interannual variations of two hierarchically related factors: El Niño Southern Oscillation (ENSO) through the Southern Oscillation Index (SOI), and precipitation. We described the effect of humans through the shape of the temporal trends of the residuals (RESTREND) of the environmental model and quantified human relative impact through the RESTREND: ANPP trend ratio. ANPP interannual variation was significantly explained by ENSO (through SOI) and precipitation in 65% of the study area. The SOI had a positive association with annual precipitation. The association between ANPP and annual precipitation was positive. RESTREND analysis was statistically significant in 92% of the area where the tested environmental model worked, representing 60% of the study area, and it was mostly negative. However, its magnitude, revealed through the RESTREND: ANPP trend ratio, was relatively mild. Our analysis revealed that most of ANPP trends were associated with climate and that even when human density is low, its incidence seems to be mainly negative.


Asunto(s)
Ecosistema , Pradera , Clima , Cambio Climático , Humanos , Lluvia
9.
Clin Cancer Res ; 25(16): 4955-4965, 2019 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-31142501

RESUMEN

PURPOSE: mAbs including cetuximab can induce antibody-dependent cellular cytotoxicity (ADCC) and cytokine production mediated via innate immune cells with the ability to recognize mAb-coated tumors. Preclinical modeling has shown that costimulation of natural killer (NK) cells via the Fc receptor and the IL12 receptor promotes NK-cell-mediated ADCC and production of cytokines. PATIENTS AND METHODS: This phase I/II trial evaluated the combination of cetuximab with IL12 for the treatment of EGFR-expressing head and neck cancer. Treatment consisted of cetuximab 500 mg/m2 i.v. every 2 weeks with either 0.2 mcg/kg or 0.3 mcg/kg IL12 s.c. on days 2 and 5 of the 2-week cycle, beginning with cycle 2. Correlative studies from blood draws obtained prior to treatment and during therapy included measurement of ADCC, serum cytokine, and chemokine analysis, determination of NK cell FcγRIIIa polymorphisms, and an analysis of myeloid-derived suppressor cell (MDSC) frequency in peripheral blood. RESULTS: The combination of cetuximab and IL12 was well tolerated. No clinical responses were observed, however, 48% of patients exhibited prolonged progression-free survival (PFS; average of 6.5 months). Compared with patients that did not exhibit clinical benefit, patients with PFS >100 days exhibited increased ADCC as therapy continued compared with baseline, greater production of IFNγ, IP-10, and TNFα at the beginning of cycle 8 compared with baseline values and had a predominance of monocytic MDSCs versus granulocytic MDSCs prior to therapy. CONCLUSIONS: Further investigation of IL12 as an immunomodulatory agent in combination with cetuximab in head and neck squamous cell carcinoma is warranted.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Adulto , Anciano , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Biomarcadores de Tumor , Cetuximab/administración & dosificación , Citocinas/biosíntesis , Esquema de Medicación , Femenino , Humanos , Interleucina-12/administración & dosificación , Masculino , Persona de Mediana Edad , Terapia Molecular Dirigida , Metástasis de la Neoplasia , Estadificación de Neoplasias , Polimorfismo Genético , Pronóstico , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/mortalidad , Resultado del Tratamiento
10.
Melanoma Res ; 29(5): 491-500, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31116161

RESUMEN

Neuroblastoma RAS viral oncogene homolog is a commonly mutated oncogene in melanoma, and therapeutic targeting of neuroblastoma RAS viral oncogene homolog has proven difficult. We characterized the expression and phenotypic functions of five recently discovered splice isoforms of neuroblastoma RAS viral oncogene homolog in melanoma. Canonical neuroblastoma RAS viral oncogene homolog (isoform-1) was expressed to the highest degree and its expression was significantly increased in melanoma metastases compared to primary lesions. Isoform-5 expression in metastases showed a significant, positive correlation with survival and tumours over-expressing isoform-5 had significantly decreased growth in a xenograft model. In contrast, over-expression of any isoform resulted in enhanced proliferation, and invasiveness was increased with over-expression of isoform-1 or isoform-2. Downstream signalling analysis indicated that the isoforms signalled differentially through the mitogen-activated protein kinase and PI3K pathways and A375 cells over-expressing isoform-2 or isoform-5 showed resistance to vemurafenib treatment in vitro. The neuroblastoma RAS viral oncogene homolog isoforms appear to play varying roles in melanoma phenotype and could potentially serve as biomarkers for therapeutic response and disease prognosis.


Asunto(s)
Empalme Alternativo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Melanoma/genética , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Neoplasias Cutáneas/metabolismo , Animales , Biomarcadores de Tumor , Línea Celular Tumoral , Proliferación Celular , Resistencia a Antineoplásicos , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Melanoma/terapia , Ratones , Ratones Desnudos , Mutación , Metástasis de la Neoplasia , Trasplante de Neoplasias , Fosfatidilinositol 3-Quinasas/metabolismo , Pronóstico , Isoformas de Proteínas , ARN Mensajero/metabolismo , Transducción de Señal/genética , Neoplasias Cutáneas/terapia , Vemurafenib/uso terapéutico
11.
Melanoma Res ; 28(5): 390-397, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30020196

RESUMEN

The NEDD8 pathway is a known activator of the ubiquitin-protease system, a complex that is partially responsible for the degradation of proteins involved in cell-cycle regulation and neoplastic growth. In this study, we evaluated the antitumor potential of MLN4924 (pevonedistat), a potent NEDD8 inhibitor. We hypothesized that MLN4924 treatment induces apoptosis in human melanoma cells. A375 and Mel39 BRAF V600E mutant melanoma cell lines were treated in vitro with MLN4924 alone or in combination with interferon-α (IFN-α) or vemurafenib - therapeutic agents utilized on melanoma patients. Annexin/propidium iodine flow cytometry analysis showed that treatment with MLN4924 for 72 h induced apoptosis in A375 and Mel39 melanoma cells with an IC50 of 1200 and 143 nmol/l, respectively. Combination therapy of A375 cells with 10 U/ml IFN-α and 1200 nmol/l MLN4924 led to a significant increase in cell death (78.2±3.7%) compared with single-agent treatment by IFN-α (17.5±2.5%) or MLN4924 (50.7±1.0%; P<0.005). Treatment of A375 cells with 1 µmol/l vemurafenib had a notable effect on cell viability. However, the addition of MLN4924 to vemurafenib had an inhibitory effect on apoptosis. Results from MTS proliferation assays indicate that MLN4924 has antiproliferative effects on melanoma cells in vitro, with the addition of IFN-α further inhibiting proliferation. Pretreatment with MLN4924 led to A375 cell sensitization to vemurafenib treatment and immunoblot analysis of MLN4924-treated cells revealed cleavage of caspase-3, caspase-7, caspase-9, and poly-ADP-ribose polymerase. These results show that MLN4924 does have an efficacy in treating melanoma in vitro alone or in combination with IFN-α, and thus it may have potential use in patients with advanced melanoma.


Asunto(s)
Ciclopentanos/uso terapéutico , Inhibidores Enzimáticos/uso terapéutico , Melanoma/tratamiento farmacológico , Pirimidinas/uso terapéutico , Neoplasias Cutáneas/tratamiento farmacológico , Línea Celular Tumoral , Ciclopentanos/farmacología , Inhibidores Enzimáticos/farmacología , Humanos , Melanoma/mortalidad , Melanoma/patología , Pirimidinas/farmacología , Neoplasias Cutáneas/mortalidad , Neoplasias Cutáneas/patología , Tasa de Supervivencia
12.
Sci Rep ; 8(1): 7152, 2018 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-29740087

RESUMEN

The lactose operon (lacTEGF) from Lactobacillus casei strain BL23 has been previously studied. The lacT gene codes for a transcriptional antiterminator, lacE and lacF for the lactose-specific phosphoenolpyruvate: phosphotransferase system (PTSLac) EIICB and EIIA domains, respectively, and lacG for the phospho-ß-galactosidase. In this work, we have shown that L. casei is able to metabolize N-acetyllactosamine (LacNAc), a disaccharide present at human milk and intestinal mucosa. The mutant strains BL153 (lacE) and BL155 (lacF) were defective in LacNAc utilization, indicating that the EIICB and EIIA of the PTSLac are involved in the uptake of LacNAc in addition to lactose. Inactivation of lacG abolishes the growth of L. casei in both disaccharides and analysis of LacG activity showed a high selectivity toward phosphorylated compounds, suggesting that LacG is necessary for the hydrolysis of the intracellular phosphorylated lactose and LacNAc. L. casei (lacAB) strain deficient in galactose-6P isomerase showed a growth rate in lactose (0.0293 ± 0.0014 h-1) and in LacNAc (0.0307 ± 0.0009 h-1) significantly lower than the wild-type (0.1010 ± 0.0006 h-1 and 0.0522 ± 0.0005 h-1, respectively), indicating that their galactose moiety is catabolized through the tagatose-6P pathway. Transcriptional analysis showed induction levels of the lac genes ranged from 130 to 320-fold in LacNAc and from 100 to 200-fold in lactose, compared to cells growing in glucose.


Asunto(s)
Amino Azúcares/metabolismo , Operón Lac/genética , Leche Humana/metabolismo , Oligosacáridos/metabolismo , Isomerasas Aldosa-Cetosa/genética , Isomerasas Aldosa-Cetosa/metabolismo , Proliferación Celular/genética , Galactosa/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiología , Lacticaseibacillus casei/genética , Lacticaseibacillus casei/metabolismo , Lactosa/metabolismo , Leche Humana/microbiología , Oligosacáridos/genética , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/genética , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/metabolismo
13.
Proc Natl Acad Sci U S A ; 114(36): 9629-9634, 2017 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-28827320

RESUMEN

Activating mutations in BRAF are found in 50% of melanomas and although treatment with BRAF inhibitors (BRAFi) is effective, resistance often develops. We now show that recently discovered NRAS isoform 2 is up-regulated in the setting of BRAF inhibitor resistance in melanoma, in both cell lines and patient tumor tissues. When isoform 2 was overexpressed in BRAF mutant melanoma cell lines, melanoma cell proliferation and in vivo tumor growth were significantly increased in the presence of BRAFi treatment. shRNA-mediated knockdown of isoform 2 in BRAFi resistant cells restored sensitivity to BRAFi compared with controls. Signaling analysis indicated decreased mitogen-activated protein kinase (MAPK) pathway signaling and increased phosphoinositol-3-kinase (PI3K) pathway signaling in isoform 2 overexpressing cells compared with isoform 1 overexpressing cells. Immunoprecipitation of isoform 2 validated a binding affinity of this isoform to both PI3K and BRAF/RAF1. The addition of an AKT inhibitor to BRAFi treatment resulted in a partial restoration of BRAFi sensitivity in cells expressing high levels of isoform 2. NRAS isoform 2 may contribute to resistance to BRAFi by facilitating PI3K pathway activation.


Asunto(s)
GTP Fosfohidrolasas/genética , Melanoma/tratamiento farmacológico , Melanoma/genética , Proteínas de la Membrana/genética , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/genética , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Movimiento Celular , Resistencia a Antineoplásicos/genética , GTP Fosfohidrolasas/antagonistas & inhibidores , GTP Fosfohidrolasas/metabolismo , Técnicas de Silenciamiento del Gen , Humanos , Indoles/uso terapéutico , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/genética , Melanoma/metabolismo , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/metabolismo , Mutación , Fosfatidilinositol 3-Quinasas/metabolismo , Isoformas de Proteínas/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Neoplásico/genética , ARN Neoplásico/metabolismo , Neoplasias Cutáneas/metabolismo , Sulfonamidas/uso terapéutico , Regulación hacia Arriba , Vemurafenib
14.
Appl Microbiol Biotechnol ; 101(1): 205-215, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27714445

RESUMEN

Lacto-N-biose (LNB) and galacto-N-biose (GNB) are major building blocks of free oligosaccharides and glycan moieties of glyco-complexes present in human milk and gastrointestinal mucosa. We have previously characterized the phospho-ß-galactosidase GnbG from Lactobacillus casei BL23 that is involved in the metabolism of LNB and GNB. GnbG has been used here in transglycosylation reactions, and it showed the production of LNB and GNB with N-acetylglucosamine and N-acetylgalactosamine as acceptors, respectively. The reaction kinetics demonstrated that GnbG can convert 69 ± 4 and 71 ± 1 % of o-nitrophenyl-ß-D-galactopyranoside into LNB and GNB, respectively. Those reactions were performed in a semi-preparative scale, and the synthesized disaccharides were purified. The maximum yield obtained for LNB was 10.7 ± 0.2 g/l and for GNB was 10.8 ± 0.3 g/l. NMR spectroscopy confirmed the molecular structures of both carbohydrates and the absence of reaction byproducts, which also supports that GnbG is specific for ß1,3-glycosidic linkages. The purified sugars were subsequently tested for their potential prebiotic properties using Lactobacillus species. The results showed that LNB and GNB were fermented by the tested strains of L. casei, Lactobacillus rhamnosus (except L. rhamnosus strain ATCC 53103), Lactobacillus zeae, Lactobacillus gasseri, and Lactobacillus johnsonii. DNA hybridization experiments suggested that the metabolism of those disaccharides in 9 out of 10 L. casei strains, all L. rhamnosus strains and all L. zeae strains tested relies upon a phospho-ß-galactosidase homologous to GnbG. The results presented here support the putative role of human milk oligosaccharides for selective enrichment of beneficial intestinal microbiota in breast-fed infants.


Asunto(s)
Disacáridos/metabolismo , Glicósido Hidrolasas/metabolismo , Mucosa Intestinal/metabolismo , Lactobacillus/metabolismo , Leche Humana/metabolismo , Prebióticos , Acetilgalactosamina/metabolismo , Acetilglucosamina/metabolismo , Disacáridos/química , Glicosilación , Cinética , Lactobacillus/enzimología , Espectroscopía de Resonancia Magnética , Hibridación de Ácido Nucleico
15.
PLoS One ; 11(11): e0166264, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27846291

RESUMEN

Polyploidy and symbiotic Epichloë fungal endophytes are common and heritable characteristics that can facilitate environmental range expansion in grasses. Here we examined geographic patterns of polyploidy and the frequency of fungal endophyte colonized plants in 29 Festuca rubra L. populations from eight geographic sites across latitudes from Spain to northernmost Finland and Greenland. Ploidy seemed to be positively and negatively correlated with latitude and productivity, respectively. However, the correlations were nonlinear; 84% of the plants were hexaploids (2n = 6x = 42), and the positive correlation between ploidy level and latitude is the result of only four populations skewing the data. In the southernmost end of the gradient 86% of the plants were tetraploids (2n = 4x = 28), whereas in the northernmost end of the gradient one population had only octoploid plants (2n = 8x = 56). Endophytes were detected in 22 out of the 29 populations. Endophyte frequencies varied among geographic sites, and populations and habitats within geographic sites irrespective of ploidy, latitude or productivity. The highest overall endophyte frequencies were found in the southernmost end of the gradient, Spain, where 69% of plants harbored endophytes. In northern Finland, endophytes were detected in 30% of grasses but endophyte frequencies varied among populations from 0% to 75%, being higher in meadows compared to riverbanks. The endophytes were detected in 36%, 30% and 27% of the plants in Faroe Islands, Iceland and Switzerland, respectively. Practically all examined plants collected from southern Finland and Greenland were endophyte-free, whereas in other geographic sites endophyte frequencies were highly variable among populations. Common to all populations with high endophyte frequencies is heavy vertebrate grazing. We propose that the detected endophyte frequencies and ploidy levels mirror past distribution history of F. rubra after the last glaciation period, and local adaptations to past or prevailing selection forces such as vertebrate grazing.


Asunto(s)
Endófitos/genética , Epichloe/genética , Festuca/genética , Ploidias , Dinamarca , Ecosistema , Endófitos/crecimiento & desarrollo , Epichloe/crecimiento & desarrollo , Festuca/crecimiento & desarrollo , Festuca/microbiología , Finlandia , Genética de Población , Islandia , España , Suiza , Simbiosis/genética
16.
Ecol Appl ; 26(5): 1370-1380, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27755747

RESUMEN

Grazing intensity elicits changes in the composition of plant functional groups in both shortgrass steppe (SGS) and northern mixed-grass prairie (NMP) in North America. How these grazing intensity-induced changes control aboveground net primary production (ANPP) responses to precipitation remains a central open question, especially in light of predicted climate changes. Here, we evaluated effects of four levels (none, light, moderate, and heavy) of long-term (>30 yr) grazing intensity in SGS and NMP on: (1) ANPP; (2) precipitation-use efficiency (PUE, ANPP : precipitation); and (3) precipitation marginal response (PMR; slope of a linear regression model between ANPP and precipitation). We advance prior work by examining: (1) the consequences of a range of grazing intensities (more grazed vs. ungrazed); and (2) how grazing-induced changes in ANPP and PUE are related both to shifts in functional group composition and physiological responses within each functional group. Spring (April-June) precipitation, the primary determinant of ANPP, was only 12% higher in NMP than in SGS, yet ANPP and PUE were 25% higher. Doubling grazing intensity in SGS and nearly doubling it in NMP reduced ANPP and PUE by only 24% and 33%, respectively. Increased grazing intensity reduced C3 graminoid biomass and increased C4 grass biomass in both grasslands. Functional group shifts affected PUE through biomass reductions, as PUE was positively associated with the relative abundance of C3 species and negatively with C4 species across both grasslands. At the community level, PMR was similar between grasslands and unaffected by grazing intensity. However, PMR of C3 graminoids in SGS was eightfold higher in the ungrazed treatment than under any grazed level. In NMP, PMR of C3 graminoids was only reduced under heavy grazing intensity. Knowing the ecological consequences of grazing intensity provides valuable information for mitigation and adaptation strategies in response to predicted climate change. For example, moderate grazing (the recommended rate) in SGS would sequester the same amount of aboveground carbon as light grazing because ANPP was nearly the same. In contrast, reductions in grazing intensity in NMP from moderate to light intensity would increase the amount of aboveground carbon sequestrated by 25% because of increased ANPP.


Asunto(s)
Crianza de Animales Domésticos , Conducta Alimentaria/fisiología , Pradera , Ganado/fisiología , Lluvia , Animales , Colorado , Poaceae/clasificación , Wyoming
19.
Appl Environ Microbiol ; 82(2): 570-7, 2016 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-26546429

RESUMEN

Human milk oligosaccharides (HMOs) are considered to play a key role in establishing and maintaining the infant gut microbiota. Lacto-N-triose forms part of both type 1 and type 2 HMOs and also of the glycan moieties of glycoproteins. Upstream of the previously characterized gene cluster involved in lacto-N-biose and galacto-N-biose metabolism from Lactobacillus casei BL23, there are two genes, bnaG and manA, encoding a ß-N-acetylglucosaminidase precursor and a mannose-6-phosphate isomerase, respectively. In this work, we show that L. casei is able to grow in the presence of lacto-N-triose as a carbon source. Inactivation of bnaG abolished the growth of L. casei on this oligosaccharide, demonstrating that BnaG is involved in its metabolism. Interestingly, whole cells of a bnaG mutant were totally devoid of ß-N-acetylglucosaminidase activity, suggesting that BnaG is an extracellular wall-attached enzyme. In addition to hydrolyzing lacto-N-triose into N-acetylglucosamine and lactose, the purified BnaG enzyme also catalyzed the hydrolysis of 3'-N-acetylglucosaminyl-mannose and 3'-N-acetylgalactosaminyl-galactose. L. casei can be cultured in the presence of 3'-N-acetylglucosaminyl-mannose as a carbon source, but, curiously, the bnaG mutant strain was not impaired in its utilization. These results indicate that the assimilation of 3'-N-acetylglucosaminyl-mannose is independent of BnaG. Enzyme activity and growth analysis with a manA-knockout mutant showed that ManA is involved in the utilization of the mannose moiety of 3'-N-acetylglucosaminyl-mannose. Here we describe the physiological role of a ß-N-acetylglucosaminidase in lactobacilli, and it supports the metabolic adaptation of L. casei to the N-acetylglucosaminide-rich gut niche.


Asunto(s)
Acetilglucosaminidasa/metabolismo , Proteínas Bacterianas/metabolismo , Pared Celular/enzimología , Lacticaseibacillus casei/enzimología , Leche Humana/microbiología , Trisacáridos/metabolismo , Acetilglucosaminidasa/genética , Proteínas Bacterianas/genética , Pared Celular/genética , Humanos , Lacticaseibacillus casei/genética , Lacticaseibacillus casei/crecimiento & desarrollo , Lacticaseibacillus casei/metabolismo , Leche Humana/metabolismo , Oligosacáridos/metabolismo
20.
Rev. ing. bioméd ; 9(18): 57-64, jul.-dic. 2015. graf
Artículo en Español | LILACS | ID: lil-769169

RESUMEN

La metrología como ciencia de las mediciones posee su utilización en el sector industrial, pero se resalta la importancia en su aplicación en el área de la salud, dado que con los procesos metrológicos se puede identificar la exactitud y precisión que pueden poseer los equipos biomédicos; de ahí la pertinencia de destacar la necesidad de desarrollar la normatividad que en el tema de metrología en equipo biomédico debe expedir aquellas organizaciones en el país que velan por la protección social relacionada con los servicios de promoción, protección y recuperación de la salud presentados en normas en cada país. Para dar cumplimiento a esto en toda institución hospitalaria en Colombia se debe realizar un proceso de habilitación, como requisito mínimo de calidad para prestar el servicio de salud, según lo establece el Decreto 2003 de 2014, donde se establece de obligatorio cumplimiento la calibración de los equipos médicos; pero no hay unos criterios únicos y normativos que determinen una debida gestión metrológica en las entidades de salud, por lo tanto este articulo pretende presentar una caracterización de la Gestión Metrológica en equipos biomédicos partiendo de normativa nacional e internacional y realizando validación en entidades prestadoras del servicio de salud, en el marco del proyecto de investigación producción más limpia en el clúster salud de la ciudad de Medellín.


Metrology as the science of measurement has its use in the industrial sector, but the importance of its application in the area of health is highlighted, since, with metrological processes the accuracy and precision of biomedical equipment can be identified; hence the relevance of emphasizing the need to develop regulations in metrology in biomedical equipment by those organizations in the country that ensure the social protection services related to the promotion, protection, and recovery found in standards in each country. To fulfill this in every hospital institution in Colombia institutions must undertake a process of availability, as a minimum requirement to provide quality health services, as established by Decree 2003 of 2014, which makes mandatory calibrating medical equipments; but there is a unique and normative standard which determine an appropriate metrological management in health institutions, so this article aims to present a characterization of metrological management in biomedical equipment based on national and international standards and performing validation care in health institutions, in the framework of the research project Cleaner Production in Medellin's health cluster.


A Metrologia, como a ciência da medição tem a sua utilização no sector industrial, mas se sublinha a importância na sua aplicação na área da saúde, como acontece com os processos metrológicos podem se identificar a exatidão e precisão que pode ter os equipamentos biomédicos; daí a relevância de enfatizar a necessidade de desenvolver as normas em tema de metrologia em equipamentos biomédicos deve emitir essas organizações no país que garantam os serviços de proteção social relacionadas com a promoção, proteção e recuperação da saúde apresentado nas normas de cada país. Para cumprir isto em cada instituição hospitalar na Colômbia deve se empreender um processo de habilitação, como requisito mínimo para prestar o serviço de saúde de qualidade, conforme o estabelecido pelo Decreto 2003 de 2014, que estabelece calibragem obrigatória dos equipamentos médicos; Mas não há uns padrões únicos e normativos que determinem uma gestão metrológica apropriada nas instituições de saúde, de modo que este artigo tem como objetivo apresentar uma caracterização da gestão metrológica em equipamentos biomédicos com base em normas nacionais e internacional e realizando validação em entidades fornecedoras de saúde, no âmbito do projeto de pesquisa mais limpa no cluster da saúde da cidade de Medellín.

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