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da Silva ACR, Ferro JA, Reinach FC, Farah CS, Furlan LR, Quaggio RB, Monteiro-Vitorello CB, Van Sluys MA, Almeida NF, Alves LMC, do Amaral AM, Bertolini MC, Camargo LEA, Camarotte G, Cannavan F, Cardozo J, Chambergo F, Ciapina LP, Cicarelli RMB, Coutinho LL, Cursino-Santos JR, El-Dorry H, Faria JB, Ferreira AJS, Ferreira RCC, Ferro MIT, Formighieri EF, Franco MC, Greggio CC, Gruber A, Katsuyama AM, Kishi LT, Leite RP, Lemos EGM, Lemos MVF, Locali EC, Machado MA, Madeira AMBN, Martinez-Rossi NM, Martins EC, Meidanis J, Menck CFM, Miyaki CY, Moon DH, Moreira LM, Novo MTM, Okura VK, Oliveira MC, Oliveira VR, Pereira HA, Rossi A, Sena JAD, Silva C, de Souza RF, Spinola LAF, Takita MA, Tamura RE, Teixeira EC, Tezza RID, Trindade dos Santos M, Truffi D, Tsai SM, White FF, Setubal JC, Kitajima JP. Comparison of the genomes of two Xanthomonas pathogens with differing host specificities. Nature 2002; 417:459-63. [PMID: 12024217 DOI: 10.1038/417459a] [Citation(s) in RCA: 803] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.
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Gómez-Ambrosi J, Silva C, Galofré JC, Escalada J, Santos S, Millán D, Vila N, Ibañez P, Gil MJ, Valentí V, Rotellar F, Ramírez B, Salvador J, Frühbeck G. Body mass index classification misses subjects with increased cardiometabolic risk factors related to elevated adiposity. Int J Obes (Lond) 2011; 36:286-94. [PMID: 21587201 DOI: 10.1038/ijo.2011.100] [Citation(s) in RCA: 401] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
CONTEXT Body mass index (BMI) is widely used as a measure of overweight and obesity, but underestimates the prevalence of both conditions, defined as an excess of body fat. OBJECTIVE We assessed the degree of misclassification on the diagnosis of obesity using BMI as compared with direct body fat percentage (BF%) determination and compared the cardiovascular and metabolic risk of non-obese and obese BMI-classified subjects with similar BF%. DESIGN We performed a cross-sectional study. SUBJECTS A total of 6123 (924 lean, 1637 overweight and 3562 obese classified according to BMI) Caucasian subjects (69% females), aged 18-80 years. METHODS BMI, BF% determined by air displacement plethysmography and well-established blood markers of insulin sensitivity, lipid profile and cardiovascular risk were measured. RESULTS We found that 29% of subjects classified as lean and 80% of individuals classified as overweight according to BMI had a BF% within the obesity range. Importantly, the levels of cardiometabolic risk factors, such as C-reactive protein, were higher in lean and overweight BMI-classified subjects with BF% within the obesity range (men 4.3 ± 9.2, women 4.9 ± 19.5 mg l(-1)) as well as in obese BMI-classified individuals (men 4.2 ± 5.5, women 5.1 ± 13.2 mg l(-1)) compared with lean volunteers with normal body fat amounts (men 0.9 ± 0.5, women 2.1 ± 2.6 mg l(-1); P<0.001 for both genders). CONCLUSION Given the elevated concentrations of cardiometabolic risk factors reported herein in non-obese individuals according to BMI but obese based on body fat, the inclusion of body composition measurements together with morbidity evaluation in the routine medical practice both for the diagnosis and the decision-making for instauration of the most appropriate treatment of obesity is desirable.
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Research Support, Non-U.S. Gov't |
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Beljonne D, Pourtois G, Silva C, Hennebicq E, Herz LM, Friend RH, Scholes GD, Setayesh S, Mullen K, Bredas JL. Interchain vs. intrachain energy transfer in acceptor-capped conjugated polymers. Proc Natl Acad Sci U S A 2002; 99:10982-7. [PMID: 12177444 PMCID: PMC123196 DOI: 10.1073/pnas.172390999] [Citation(s) in RCA: 233] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The energy-transfer processes taking place in conjugated polymers are investigated by means of ultrafast spectroscopy and correlated quantum-chemical calculations applied to polyindenofluorenes end-capped with a perylene derivative. Comparison between the time-integrated luminescence and transient absorption spectra measured in solution and in films allows disentangling of the contributions arising from intrachain and from interchain energy-migration phenomena. Intrachain processes dominate in solution where photoexcitation of the polyindenofluorene units induces a rather slow energy transfer to the perylene end moieties. In films, close contacts between chains favors interchain transport of the excited singlet species (from the conjugated bridge of one chain to the perylene unit of a neighboring one); this process is characterized by a 1-order-of-magnitude increase in transfer rate with respect to solution. This description is supported fully by the results of quantum-chemical calculations that go beyond the usual point-dipole model approximation and account for geometric relaxation phenomena in the excited state before energy migration. The calculations indicate a two-step mechanism for intrachain energy transfer with hopping along the conjugated chains as the rate-limiting step; the higher efficiency of the interchain transfer process is mainly due to larger electronic coupling matrix elements between closely lying chains.
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Akerib DS, Alsum S, Araújo HM, Bai X, Bailey AJ, Balajthy J, Beltrame P, Bernard EP, Bernstein A, Biesiadzinski TP, Boulton EM, Bramante R, Brás P, Byram D, Cahn SB, Carmona-Benitez MC, Chan C, Chiller AA, Chiller C, Currie A, Cutter JE, Davison TJR, Dobi A, Dobson JEY, Druszkiewicz E, Edwards BN, Faham CH, Fiorucci S, Gaitskell RJ, Gehman VM, Ghag C, Gibson KR, Gilchriese MGD, Hall CR, Hanhardt M, Haselschwardt SJ, Hertel SA, Hogan DP, Horn M, Huang DQ, Ignarra CM, Ihm M, Jacobsen RG, Ji W, Kamdin K, Kazkaz K, Khaitan D, Knoche R, Larsen NA, Lee C, Lenardo BG, Lesko KT, Lindote A, Lopes MI, Manalaysay A, Mannino RL, Marzioni MF, McKinsey DN, Mei DM, Mock J, Moongweluwan M, Morad JA, Murphy ASJ, Nehrkorn C, Nelson HN, Neves F, O'Sullivan K, Oliver-Mallory KC, Palladino KJ, Pease EK, Phelps P, Reichhart L, Rhyne C, Shaw S, Shutt TA, Silva C, Solmaz M, Solovov VN, Sorensen P, Stephenson S, Sumner TJ, Szydagis M, Taylor DJ, Taylor WC, Tennyson BP, Terman PA, Tiedt DR, To WH, Tripathi M, Tvrznikova L, Uvarov S, Verbus JR, Webb RC, White JT, Whitis TJ, Witherell MS, Wolfs FLH, Xu J, Yazdani K, Young SK, et alAkerib DS, Alsum S, Araújo HM, Bai X, Bailey AJ, Balajthy J, Beltrame P, Bernard EP, Bernstein A, Biesiadzinski TP, Boulton EM, Bramante R, Brás P, Byram D, Cahn SB, Carmona-Benitez MC, Chan C, Chiller AA, Chiller C, Currie A, Cutter JE, Davison TJR, Dobi A, Dobson JEY, Druszkiewicz E, Edwards BN, Faham CH, Fiorucci S, Gaitskell RJ, Gehman VM, Ghag C, Gibson KR, Gilchriese MGD, Hall CR, Hanhardt M, Haselschwardt SJ, Hertel SA, Hogan DP, Horn M, Huang DQ, Ignarra CM, Ihm M, Jacobsen RG, Ji W, Kamdin K, Kazkaz K, Khaitan D, Knoche R, Larsen NA, Lee C, Lenardo BG, Lesko KT, Lindote A, Lopes MI, Manalaysay A, Mannino RL, Marzioni MF, McKinsey DN, Mei DM, Mock J, Moongweluwan M, Morad JA, Murphy ASJ, Nehrkorn C, Nelson HN, Neves F, O'Sullivan K, Oliver-Mallory KC, Palladino KJ, Pease EK, Phelps P, Reichhart L, Rhyne C, Shaw S, Shutt TA, Silva C, Solmaz M, Solovov VN, Sorensen P, Stephenson S, Sumner TJ, Szydagis M, Taylor DJ, Taylor WC, Tennyson BP, Terman PA, Tiedt DR, To WH, Tripathi M, Tvrznikova L, Uvarov S, Verbus JR, Webb RC, White JT, Whitis TJ, Witherell MS, Wolfs FLH, Xu J, Yazdani K, Young SK, Zhang C. Results from a Search for Dark Matter in the Complete LUX Exposure. PHYSICAL REVIEW LETTERS 2017; 118:021303. [PMID: 28128598 DOI: 10.1103/physrevlett.118.021303] [Show More Authors] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Indexed: 06/06/2023]
Abstract
We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×10^{4} kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV c^{-2}, WIMP-nucleon spin-independent cross sections above 2.2×10^{-46} cm^{2} are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10^{-46} cm^{2} at 50 GeV c^{-2}.
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Johnston JB, Silva C, Holden J, Warren KG, Clark AW, Power C. Monocyte activation and differentiation augment human endogenous retrovirus expression: implications for inflammatory brain diseases. Ann Neurol 2001; 50:434-42. [PMID: 11601494 DOI: 10.1002/ana.1131] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Human endogenous retroviruses (HERVs) have been implicated as causative agents in diseases characterized by inflammation and macrophage activation, such as multiple sclerosis. Because monocyte activation and differentiation influence retroviral transcription and replication, we investigated the contribution of these processes to the expression of four HERV families (HERV-W, HERV-K, HERV-E, and HERV-H) in human monocytes, and autopsied brain tissue from patients with brain diseases associated with increased macrophage activity. Reverse transcriptase-polymerase chain reaction analysis of primary macrophages and U937 monocytoid cells stimulated with phorbol-12-myristate-13-acetate or lipopolysaccharide revealed three- to ninefold increases in HERV-W, HERV-K, and HERV-H RNA levels. In addition, elevated reverse transcriptase activity and HERV RNA were detectable in supernatants from PMA-stimulated U937 cultures, properties that could be attenuated with the inhibitor of monocyte differentiation threonine-lysine-proline. In contrast, stimulation of monocytes decreased or had no effect on HERV-E expression. Compared with controls, HERV-W and HERV-K expression was increased in brain tissue from patients with multiple sclerosis or human immunodeficiency virus infection or AIDS, with concomitant elevated tumor necrosis factor-alpha levels. Similarly, elevated HERV-W levels were detected in patients with Alzheimer's dementia only when tumor necrosis factor-alpha expression was also evident (2 of 6 cases). The detection of several HERVs in inflammatory brain diseases and the capacity to augment HERV expression in monocytes with compounds that influence cellular activity suggest that increased expression of these viruses is a consequence of increased immune activity rather than causative of distinct diseases.
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Abstract
Although violence against women is recognized as a major public health problem, few interventions have been developed to reduce abuse. In this study, 132 pregnant women received three counseling sessions that were designed to reduce further abuse. A comparison group of 67 abused women were offered wallet-sized cards listing community resources for abuse. Women in both groups were followed at 6 months and 12 months post-delivery. Using repeated measures MANCOVA with entry scores as a covariate, we found significantly less violence reported by women in the intervention group than by women in the comparison group.
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Letter |
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Akerib DS, Araújo HM, Bai X, Bailey AJ, Balajthy J, Bedikian S, Bernard E, Bernstein A, Bolozdynya A, Bradley A, Byram D, Cahn SB, Carmona-Benitez MC, Chan C, Chapman JJ, Chiller AA, Chiller C, Clark K, Coffey T, Currie A, Curioni A, Dazeley S, de Viveiros L, Dobi A, Dobson J, Dragowsky EM, Druszkiewicz E, Edwards B, Faham CH, Fiorucci S, Flores C, Gaitskell RJ, Gehman VM, Ghag C, Gibson KR, Gilchriese MGD, Hall C, Hanhardt M, Hertel SA, Horn M, Huang DQ, Ihm M, Jacobsen RG, Kastens L, Kazkaz K, Knoche R, Kyre S, Lander R, Larsen NA, Lee C, Leonard DS, Lesko KT, Lindote A, Lopes MI, Lyashenko A, Malling DC, Mannino R, McKinsey DN, Mei DM, Mock J, Moongweluwan M, Morad J, Morii M, Murphy ASJ, Nehrkorn C, Nelson H, Neves F, Nikkel JA, Ott RA, Pangilinan M, Parker PD, Pease EK, Pech K, Phelps P, Reichhart L, Shutt T, Silva C, Skulski W, Sofka CJ, Solovov VN, Sorensen P, Stiegler T, O'Sullivan K, Sumner TJ, Svoboda R, Sweany M, Szydagis M, Taylor D, Tennyson B, Tiedt DR, Tripathi M, Uvarov S, Verbus JR, Walsh N, Webb R, White JT, White D, Witherell MS, Wlasenko M, Wolfs FLH, et alAkerib DS, Araújo HM, Bai X, Bailey AJ, Balajthy J, Bedikian S, Bernard E, Bernstein A, Bolozdynya A, Bradley A, Byram D, Cahn SB, Carmona-Benitez MC, Chan C, Chapman JJ, Chiller AA, Chiller C, Clark K, Coffey T, Currie A, Curioni A, Dazeley S, de Viveiros L, Dobi A, Dobson J, Dragowsky EM, Druszkiewicz E, Edwards B, Faham CH, Fiorucci S, Flores C, Gaitskell RJ, Gehman VM, Ghag C, Gibson KR, Gilchriese MGD, Hall C, Hanhardt M, Hertel SA, Horn M, Huang DQ, Ihm M, Jacobsen RG, Kastens L, Kazkaz K, Knoche R, Kyre S, Lander R, Larsen NA, Lee C, Leonard DS, Lesko KT, Lindote A, Lopes MI, Lyashenko A, Malling DC, Mannino R, McKinsey DN, Mei DM, Mock J, Moongweluwan M, Morad J, Morii M, Murphy ASJ, Nehrkorn C, Nelson H, Neves F, Nikkel JA, Ott RA, Pangilinan M, Parker PD, Pease EK, Pech K, Phelps P, Reichhart L, Shutt T, Silva C, Skulski W, Sofka CJ, Solovov VN, Sorensen P, Stiegler T, O'Sullivan K, Sumner TJ, Svoboda R, Sweany M, Szydagis M, Taylor D, Tennyson B, Tiedt DR, Tripathi M, Uvarov S, Verbus JR, Walsh N, Webb R, White JT, White D, Witherell MS, Wlasenko M, Wolfs FLH, Woods M, Zhang C. First results from the LUX dark matter experiment at the Sanford underground research facility. PHYSICAL REVIEW LETTERS 2014; 112:091303. [PMID: 24655239 DOI: 10.1103/physrevlett.112.091303] [Show More Authors] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Indexed: 06/03/2023]
Abstract
The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota). The LUX cryostat was filled for the first time in the underground laboratory in February 2013. We report results of the first WIMP search data set, taken during the period from April to August 2013, presenting the analysis of 85.3 live days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10(-46) cm(2) at a WIMP mass of 33 GeV/c(2). We find that the LUX data are in disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.
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Sodhi A, Gong J, Silva C, Qian D, Barnes PF. Clinical correlates of interferon gamma production in patients with tuberculosis. Clin Infect Dis 1997; 25:617-20. [PMID: 9314449 DOI: 10.1086/513769] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
To determine if the capacity to produce interferon (IFN) gamma is related to the clinical manifestations of tuberculosis, we correlated Mycobacterium tuberculosis-induced IFN-gamma production by peripheral blood mononuclear cells (PBMCs) with clinical, radiographic, and laboratory variables for 63 human immunodeficiency virus (HIV)-negative patients and 43 HIV-positive patients with tuberculosis. For HIV-negative patients whose chest radiographs showed moderately advanced disease, the mean IFN-gamma concentration +/- SD was 1,639 +/- 388 pg/mL, whereas that for patients with far-advanced disease was 327 +/- 100 pg/mL (P = .0001). For HIV-infected patients who had only pleuropulmonary disease, the mean IFN-gamma concentration was 1,002 +/- 257 pg/mL, whereas that for patients with disease outside the lungs and pleura was 149 +/- 55 pg/mL (P = .0004). Multivariate analysis confirmed that the radiographic extent of disease and the site of disease were the only independent predictors of IFN-gamma production in HIV-negative and HIV-infected patients (P < or = .001). We conclude that reduced IFN-gamma production by PBMCs is a marker of severe tuberculosis in both HIV-negative and HIV-infected patients with tuberculosis.
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Silva C, Rio ME, Cruz F. Desensitization of bladder sensory fibers by intravesical resiniferatoxin, a capsaicin analog: long-term results for the treatment of detrusor hyperreflexia. Eur Urol 2000; 38:444-52. [PMID: 11025384 DOI: 10.1159/000020322] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVES To assess the pungency and the desensitizing effects of intravesical resiniferatoxin, an ultrapotent capsaicin analog, in patients with detrusor hyperreflexia. METHODS Fourteen patients with detrusor hyperreflexia were instilled during 30 min, without any form of local anesthesia, with 100 ml (or the bladder capacity if lower than that volume) of 50 or 100 nM resiniferatoxin solutions in 10% alcohol in saline. Patients were evaluated by voiding chart and urodynamic tests (volume to first contraction, maximal cystometric capacity, maximal detrusor pressure, icewater test) at 14, 30, 60, and 90 days and every 3 months thereafter RESULTS Resiniferatoxin instillation did not evoke pain or temporary worsening of urinary symptoms. Treatment improved or abolished incontinence in 9 out of 12 incontinent patients. Mean urinary frequency decreased from 14.2+/-6.4 to 10.3+/-3.2 at 3 months (p = 0.01). At this time point, mean maximal cystometric capacity increased from 182.3+/-119.8 to 330.0+/-201.6 ml (p = 0.01) and the ice water test, positive in 13 cases, became negative in 8 of them. Maximal detrusor pressure was not modified by the treatment. The effect was long-lasting, reaching 12 months in 7 cases. CONCLUSIONS The absence of irritative symptoms during bladder instillation of resiniferatoxin and the rapid onset of desensitization make this vanilloid superior to capsaicin for the treatment of detrusor hyperreflexia.
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Stachenfeld NS, Silva C, Keefe DL. Estrogen modifies the temperature effects of progesterone. J Appl Physiol (1985) 2000; 88:1643-9. [PMID: 10797125 DOI: 10.1152/jappl.2000.88.5.1643] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To test the hypothesis that progestin-mediated increases in resting core temperature and the core temperature threshold for sweating onset are counteracted by estrogen, we studied eight women (24 +/- 2 yr) at 27 degrees C rest, during 20 min of passive heating (35 degrees C), and during 40 min of exercise at 35 degrees C. Subjects were tested four times, during the early follicular and midluteal menstrual phases, after 4 wk of combined estradiol-norethindrone (progestin) oral contraceptive administration (OC E+P), and after 4 wk of progestin-only oral contraceptive administration (OC P). The order of the OC P and OC E+P were randomized. Baseline esophageal temperature (T(es)) at 27 degrees C was higher (P < 0.05) in the luteal phase (37.08 +/- 0.21 degrees C) and in OC P (37.60 +/- 0.31 degrees C) but not during OC E+P (37.04 +/- 0.23 degrees C) compared with the follicular phase (36.66 +/- 0.21 degrees C). T(es) remained above follicular phase levels throughout passive heating and exercise during OC P, whereas T(es) in the luteal phase was greater than in the follicular phase throughout exercise (P < 0.05). The T(es) threshold for sweating was also greater in the luteal phase (38.02 +/- 0.28 degrees C) and OC P (38.07 +/- 0.17 degrees C) compared with the follicular phase (37.32 +/- 0.11 degrees C) and OC E+P (37.46 +/- 0.18 degrees C). Progestin administration raised the T(es) threshold for sweating during OC P, but this effect was not present when estrogen was administered with progestin, suggesting that estrogen modifies progestin-related changes in temperature regulation. These data are also consistent with previous findings that estrogen lowers the thermoregulatory operating point.
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Stachenfeld NS, Silva C, Keefe DL, Kokoszka CA, Nadel ER. Effects of oral contraceptives on body fluid regulation. J Appl Physiol (1985) 1999; 87:1016-25. [PMID: 10484572 DOI: 10.1152/jappl.1999.87.3.1016] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To test the hypothesis that estrogen reduces the operating point for osmoregulation of arginine vasopressin (AVP), thirst, and body water balance, we studied nine women (25 +/- 1 yr) during 150 min of dehydrating exercise followed by 180 min of ad libitum rehydration. Subjects were tested six different times, during the early-follicular (twice) and midluteal (twice) menstrual phases and after 4 wk of combined [estradiol-norethindrone (progestin), OC E + P] and 4 wk of norethindrone (progestin only, OC P) oral contraceptive administration, in a randomized crossover design. Basal plasma osmolality (P(osm)) was lower in the luteal phase (281 +/- 1 mosmol/kgH(2)O, combined means, P < 0.05), OC E + P (281 +/- 1 mosmol/kgH(2)O, P < 0.05), and OC P (282 +/- 1 mosmol/kgH(2)O, P < 0. 05) than in the follicular phase (286 +/- 1 mosmol/kgH(2)O, combined means). High plasma estradiol concentration lowered the P(osm) threshold for AVP release during the luteal phase and during OC E + P [x-intercepts, 282 +/- 2, 278 +/- 2, 276 +/- 2, and 280 +/- 2 mosmol/kgH(2)O, for follicular, luteal (combined means), OC E + P, and OC P, respectively; P < 0.05, luteal phase and OC E + P vs. follicular phase] during exercise dehydration, and 17beta-estradiol administration lowered the P(osm) threshold for thirst stimulation [x-intercepts, 280 +/- 2, 279 +/- 2, 276 +/- 2, and 280 +/- 2 mosmol/kgH(2)O for follicular, luteal, OC E + P, and OC P, respectively; P < 0.05, OC E + P vs. follicular phase], without affecting body fluid balance. When plasma 17beta-estradiol concentration was high, P(osm) was low throughout rest, exercise, and rehydration, but plasma arginine vasopressin concentration, thirst, and body fluid retention were unchanged, indicating a lowering of the osmotic operating point for body fluid regulation.
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Rodríguez A, Gómez-Ambrosi J, Catalán V, Rotellar F, Valentí V, Silva C, Mugueta C, Pulido MR, Vázquez R, Salvador J, Malagón MM, Colina I, Frühbeck G. The ghrelin O-acyltransferase-ghrelin system reduces TNF-α-induced apoptosis and autophagy in human visceral adipocytes. Diabetologia 2012; 55:3038-50. [PMID: 22869322 DOI: 10.1007/s00125-012-2671-5] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/25/2012] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Proinflammatory and proapoptotic cytokines such as TNF-α are upregulated in human obesity. We evaluated the association between ghrelin isoforms (acylated and desacyl ghrelin) and TNF-α in obesity and obesity-associated type 2 diabetes, as well as the potential role of ghrelin in the control of apoptosis and autophagy in human adipocytes. METHODS Plasma concentrations of the ghrelin isoforms and TNF-α were measured in 194 participants. Ghrelin and ghrelin O-acyltransferase (GOAT) levels were analysed by western-blot, immunohistochemistry and real-time PCR in 53 biopsies of human omental adipose tissue. We also determined the effect of acylated and desacyl ghrelin (10 to 1,000 pmol/l) on TNF-α-induced apoptosis and autophagy-related molecules in omental adipocytes. RESULTS Circulating concentrations of acylated ghrelin and TNF-α were increased, whereas desacyl ghrelin levels were decreased in obesity-associated type 2 diabetes. Ghrelin and GOAT were produced in omental and subcutaneous adipose tissue. Visceral adipose tissue from obese patients with type 2 diabetes showed higher levels of GOAT, increased adipocyte apoptosis and increased expression of the autophagy-related genes ATG5, BECN1 and ATG7. In differentiating human omental adipocytes, incubation with acylated and desacyl ghrelin reduced TNF-α-induced activation of caspase-8 and caspase-3, and cell death. In addition, acylated ghrelin reduced the basal expression of the autophagy-related genes ATG5 and ATG7, while desacyl ghrelin inhibited the TNF-α-induced increase of ATG5, BECN1 and ATG7 expression. CONCLUSIONS/INTERPRETATION Apoptosis and autophagy are upregulated in human visceral adipose tissue of patients with type 2 diabetes. Acylated and desacyl ghrelin reduce TNF-α-induced apoptosis and autophagy in human visceral adipocytes.
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McFarlane J, Parker B, Soeken K, Silva C, Reel S. Safety behaviors of abused women after an intervention during pregnancy. J Obstet Gynecol Neonatal Nurs 1998; 27:64-9. [PMID: 9475129 DOI: 10.1111/j.1552-6909.1998.tb02592.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE To evaluate an intervention protocol, administered during pregnancy, for increasing safety-seeking behaviors of abused women. DESIGN Prospective, ethnically stratified cohort analysis. SETTING Public prenatal clinics. PARTICIPANTS Pregnant women reporting physical or sexual abuse in the year before or during the present pregnancy. One hundred thirty-two women met study criteria, received the intervention, and were followed for 1 year after the completion of the pregnancy. INTERVENTION Three education, advocacy, and community referral sessions that included information on safety behaviors. MAIN OUTCOME MEASURE Adoption of safety behaviors by abused women. Safety behaviors were measured before the intervention, twice during pregnancy, and at 2, 6, and 12 months after completion of the pregnancy. RESULTS Repeated measures analysis of variance showed a significant increase in adoption of each safety behavior (p < .0001), with most behaviors showing a significant increase after the first intervention session. CONCLUSIONS Pregnant women who were abused and were offered an intervention protocol report a significant increase in safety behavior adoption during and after pregnancy. Abuse during pregnancy is common. Identification of abuse and immediate clinical intervention that includes information about safety behaviors can result in safety behavior adoption that may prevent future abuse and increase the safety and well-being of women and infants.
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Johnston JB, Zhang K, Silva C, Shalinsky DR, Conant K, Ni W, Corbett D, Yong VW, Power C. HIV-1 Tat neurotoxicity is prevented by matrix metalloproteinase inhibitors. Ann Neurol 2001; 49:230-41. [PMID: 11220743 DOI: 10.1002/1531-8249(20010201)49:2<230::aid-ana43>3.0.co;2-o] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The release of potentially neurotoxic molecules by HIV-infected brain macrophages is accompanied by neuronal injury and death that results in the development of HIV-associated dementia (HAD). Among the potential neurotoxins implicated in the development of HAD is the HIV-1 transactivating protein, Tat. To investigate the mechanism by which Tat causes neurotoxicity, brain-derived Tat sequences from nondemented (Tat-ND) and demented (Tat-HAD) AIDS patients, which differed primarily in the augmenting region of Tat, were expressed in U937 monoblastoid cells and primary human macrophages. Cells expressing Tat-HAD protein exhibited elevated matrix metalloproteinase (MMP)-2 and -7 release and activation, but cells expressing Tat-ND did not exhibit enhanced MMP expression. Conditioned media from Tat-HAD-transfected cells caused significantly greater neuronal death (15.4 +/- 4.3%) than did Tat-ND (4.4 +/- 2.1%) or nontransfected (2.1 +/- 0.8%) cell-derived conditioned media. The neurotoxicity induced by Tat-HAD was inhibited by anti-MMP-2 or -7 antibodies (p < 0.005) but not by antibodies against MMP-9 or Tat. Similarly, scid/nod mice receiving striatal implants of Tat-HAD-transfected cells exhibited greater neurobehavioral abnormalities and neuronal loss (p < 0.005) than did animals receiving Tat-ND or nontransfected cells, which were reduced by treatment with the MMP inhibitor prinomastat (p < 0.005). These findings indicate that Tat causes neuronal death through an indirect mechanism that is Tat sequence dependent and involves the induction of MMPs.
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Terraf MCL, Juárez Tomás MS, Nader-Macías MEF, Silva C. Screening of biofilm formation by beneficial vaginal lactobacilli and influence of culture media components. J Appl Microbiol 2012; 113:1517-29. [PMID: 22897406 DOI: 10.1111/j.1365-2672.2012.05429.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 07/31/2012] [Accepted: 08/03/2012] [Indexed: 12/22/2022]
Abstract
AIMS To assess the ability of vaginal lactobacilli to form biofilm under different culture conditions and to determine the relationship between their growth and the capability of biofilm formation by selected strains. METHODS AND RESULTS Fifteen Lactobacillus strains from human vagina were tested for biofilm formation by crystal violet staining. Only Lactobacillus rhamnosus Centro de Referencia para Lactobacilos Culture Collection (CRL) 1332, Lact. reuteri CRL 1324 and Lact. delbrueckii CRL 1510 were able to grow and form biofilm in culture media without Tween 80. However, Lact. gasseri CRL 1263 (a non-biofilm-forming strain) did not grow in these media. Scanning electron microscopy showed that Lact. rhamnosus CRL 1332 and Lact. reuteri CRL 1324 formed a highly structured biofilm, but only Lact. reuteri CRL 1324 showed a high amount of extracellular material in medium without Tween. CONCLUSIONS Biofilm formation was significantly influenced by the strain, culture medium, inoculum concentration, microbial growth and chemical nature of the support used for the assay. SIGNIFICANCE AND IMPACTS OF THE STUDY The results allow the selection of biofilm-forming vaginal Lactobacillus strains and the conditions and factors that affect this phenomenon.
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Research Support, Non-U.S. Gov't |
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Catalán V, Gómez-Ambrosi J, Rotellar F, Silva C, Rodríguez A, Salvador J, Gil MJ, Cienfuegos JA, Frühbeck G. Validation of endogenous control genes in human adipose tissue: relevance to obesity and obesity-associated type 2 diabetes mellitus. Horm Metab Res 2007; 39:495-500. [PMID: 17611901 DOI: 10.1055/s-2007-982502] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The aim of the present study was to test the influence of obesity and the presence of type 2 diabetes mellitus (T2DM) on the expression of ten housekeeping genes and of the 18S rRNA in a group of human adipose tissue samples from the omental and subcutaneous depot. Adipose tissue biopsies were obtained by laparoscopic surgery from lean and obese patients. After the extraction, mRNA levels in adipose tissue samples were quantified by real-time PCR using the commercial HUMAN ENDOGENOUS CONTROL PLATES. From the genes analyzed, 18S rRNA exhibited the most stable expression levels in both depots regardless of the pathophysiological conditions of obesity and obesity-associated T2DM. Contrarily, GAPD was the gene with the highest variation in its expression levels, being upregulated (8.0-fold) in the obese group and downregulated (3.5-fold) in obesity-associated T2DM. Our results show that 18S rRNA may be the most suitable gene for normalization in expression studies performed in human adipose tissue samples obtained from patients suffering from obesity and/or obesity-associated T2DM, whereas GAPD is less appropriate for comparison purposes under these circumstances.
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Guilherme L, Oshiro SE, Faé KC, Cunha-Neto E, Renesto G, Goldberg AC, Tanaka AC, Pomerantzeff PM, Kiss MH, Silva C, Guzman F, Patarroyo ME, Southwood S, Sette A, Kalil J. T-cell reactivity against streptococcal antigens in the periphery mirrors reactivity of heart-infiltrating T lymphocytes in rheumatic heart disease patients. Infect Immun 2001; 69:5345-51. [PMID: 11500404 PMCID: PMC98644 DOI: 10.1128/iai.69.9.5345-5351.2001] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
T-cell molecular mimicry between streptococcal and heart proteins has been proposed as the triggering factor leading to autoimmunity in rheumatic heart disease (RHD). We searched for immunodominant T-cell M5 epitopes among RHD patients with defined clinical outcomes and compared the T-cell reactivities of peripheral blood and intralesional T cells from patients with severe RHD. The role of HLA class II molecules in the presentation of M5 peptides was also evaluated. We studied the T-cell reactivity against M5 peptides and heart proteins on peripheral blood mononuclear cells (PBMC) from 74 RHD patients grouped according to the severity of disease, along with intralesional and peripheral T-cell clones from RHD patients. Peptides encompassing residues 1 to 25, 81 to 103, 125 to 139, and 163 to 177 were more frequently recognized by PBMC from RHD patients than by those from controls. The M5 peptide encompassing residues 81 to 96 [M5(81-96) peptide] was most frequently recognized by PBMC from HLA-DR7+ DR53+ patients with severe RHD, and 46.9% (15 of 32) and 43% (3 of 7) of heart-infiltrating and PBMC-derived peptide-reactive T-cell clones, respectively, recognized the M5(81-103) region. Heart proteins were recognized more frequently by PBMC from patients with severe RHD than by those from patients with mild RHD. The similar pattern of T-cell reactivity found with both peripheral blood and heart-infiltrating T cells is consistent with the migration of M-protein-sensitized T cells to the heart tissue. Conversely, the presence of heart-reactive T cells in the PBMC of patients with severe RHD also suggests a spillover of sensitized T cells from the heart lesion.
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McFarlane J, Soeken K, Reel S, Parker B, Silva C. Resource use by abused women following an intervention program: associated severity of abuse and reports of abuse ending. Public Health Nurs 1997; 14:244-50. [PMID: 9270289 DOI: 10.1111/j.1525-1446.1997.tb00297.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Although violence against women is recognized as major public health problem, little is known about the effectiveness of interventions. To evaluate severity of abuse and use of community resources following an intervention program, 132 pregnant abused women received three counseling sessions in a prenatal setting. A comparison group of 67 abused women were offered a wallet-sized card listing community resources for violence. Resource use, severity of abuse, and reports of the abuse ending were measured for both groups at 6 and 12 months after delivery. Resource use was significantly (p < .001) related to severity of abuse, irrespective of whether the woman had received the intervention. Women using resources at 6 months were also users at 12 months. These findings indicate a "survivorship model" whereby abused women assertively and persistently seek a variety of community resources to end the abuse. The recommendation that primary care providers go beyond traditional identification and referral for abuse to coordination and evaluation of service delivery is discussed.
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Clinical Trial |
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Beljonne D, Hennebicq E, Daniel C, Herz LM, Silva C, Scholes GD, Hoeben FJM, Jonkheijm P, Schenning APHJ, Meskers SCJ, Phillips RT, Friend RH, Meijer EW. Excitation Migration along Oligophenylenevinylene-Based Chiral Stacks: Delocalization Effects on Transport Dynamics. J Phys Chem B 2005; 109:10594-604. [PMID: 16852286 DOI: 10.1021/jp050792p] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atomistic models based on quantum-chemical calculations are combined with time-resolved spectroscopic investigations to explore the migration of electronic excitations along oligophenylenevinylene-based chiral stacks. It is found that the usual Pauli master equation (PME) approach relying on uncoherent transport between individual chromophores underestimates the excitation diffusion dynamics, monitored here by the time decay of the transient polarization anisotropy. A better agreement to experiment is achieved when accounting for excitation delocalization among acceptor molecules, as implemented in a modified version of the PME model. The same models are applied to study light harvesting and trapping in guest-host systems built from oligomers of different lengths.
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Abstract
In a community sample of 102 Portuguese white women we evaluated the relationship between osteoporosis and indexes of psychopathology and well-being. Depressive symptoms were assessed by the Beck Depression Inventory (BDI), psychopathology by the Hopkins Symptom Checklist-90 Revised (SCL-90-R), and quality of life using the Psychological General Well-Being Index. A questionnaire comprising social, demographic, clinical, and behavioral characteristics was also used. The sample prevalence of osteoporosis was 47.1%. Women with osteoporosis presented significantly higher scores on the total BDI (16+/-9 vs. 13+/-10, p=0.045) and lower scores in the hostility (0.8+/-0.6 vs. 1.2+/-0.7, p=0.012) and phobic anxiety (1.1+/-0.8 vs. 1.5+/-0.9, p=0.041) subscales of the SCL-90-R. No differences were found regarding mean general well-being scores (62+/-17 vs. 64+/-19, p=0.665). This study showed that women with osteoporosis have significantly higher levels of depressive symptoms and a corresponding higher prevalence of depression, independent of other factors strongly associated with osteoporosis, such as age or body mass index.
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Silva C, McFarlane J, Soeken K, Parker B, Reel S. Symptoms of post-traumatic stress disorder in abused women in a primary care setting. J Womens Health (Larchmt) 1997; 6:543-52. [PMID: 9356977 DOI: 10.1089/jwh.1997.6.543] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Abuse is a major source of trauma to women, and post-traumatic stress disorder (PTSD) results from exposure to extreme trauma. To describe the relationship between symptoms of PTSD and severity of abuse, an ethnically stratified cohort of 131 abused women in a primary care setting was interviewed. Symptoms of PTSD, both intrusion (i.e., trouble falling asleep, strong waves of feelings about the abuse) and avoidance (i.e., trying not to think or talk about the abuse, staying away from reminders of the abuse), were significantly (p < 0.01) correlated to severity of abuse, regardless of ethnicity. When asked about childhood physical or sexual abuse, women reporting physical abuse had significantly (p < 0.05) higher intrusion scores, whereas those reporting sexual abuse had significantly (p < 0.004) higher avoidance scores. Sixty-five percent of the women reported dreams, flashbacks, or terror attacks and had significantly (p < 0.001) higher mean results on both intrusion and avoidance. The need to offer abused women information about the connection between severity of abuse and symptoms of PTSD is discussed. We recommend that clinicians ask all abused women about dreams, flashbacks, or terror attacks to assess for further symptoms of PTSD.
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Gómez-Ambrosi J, Rodríguez A, Catalán V, Ramírez B, Silva C, Rotellar F, Gil MJ, Salvador J, Frühbeck G. Serum retinol-binding protein 4 is not increased in obesity or obesity-associated type 2 diabetes mellitus, but is reduced after relevant reductions in body fat following gastric bypass. Clin Endocrinol (Oxf) 2008; 69:208-15. [PMID: 18081728 DOI: 10.1111/j.1365-2265.2007.03156.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Controversy exists regarding the elevation of serum retinol-binding protein 4 (RBP4) in human obesity and type 2 diabetes mellitus (T2DM). In the present study, we have compared serum RBP4 in lean and obese patients with or without T2DM, and analysed the effect of weight loss on serum RBP4. DESIGN Forty-two Caucasian subjects were included in the study. Serum RBP4 was measured by ELISA and Western blot. In addition, serum RBP4 was measured in 21 morbidly obese patients before and after 4, 8 and 15 months of weight loss following Roux-en-Y gastric bypass (RYGBP). RESULTS No significant effect of either obesity or diabetes on serum RBP4 was observed. Serum RBP4 concentrations (measured by either ELISA or Western blot) did not correlate with body mass index (BMI), body fat or any indicator of glucose metabolism or insulin resistance. Weight loss following RYGBP did not modify serum RBP4 at 15 months (P = 0.472). However, the variations in serum RBP4 were significantly associated with the reduction in body fat (r = 0.48; P = 0.026). Patients loosing over 20% of fat mass (n = 11) showed significantly different RBP4 concentrations compared to those individuals exhibiting smaller adiposity reductions (n = 10) (-11.0 +/- 6.4 vs.+5.8 +/- 3.6 mg/l; P = 0.036). Furthermore, RBP4 levels were significantly reduced at 4 (P = 0.006) and 8 (P = 0.015) months only in those patients loosing over 20% of fat mass. CONCLUSION Serum RBP4 concentrations are not increased in obese patients with or without T2DM. A decrease in RBP4 levels was only observed after surgically induced weight loss accompanied by relevant reductions in body fat. RBP4 might be considered as a dynamic marker of negative energy balance being reduced during weight loss when a negative energy balance threshold is reached. Furthermore, RBP4 variation in the first month after RYGBP may be a predictor of weight loss success.
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Controlled Clinical Trial |
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Mor M, Rivara S, Silva C, Bordi F, Plazzi PV, Spadoni G, Diamantini G, Balsamini C, Tarzia G, Fraschini F, Lucini V, Nonno R, Stankov BM. Melatonin receptor ligands: synthesis of new melatonin derivatives and comprehensive comparative molecular field analysis (CoMFA) study. J Med Chem 1998; 41:3831-44. [PMID: 9748358 DOI: 10.1021/jm9810093] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The CoMFA methodology was applied to melatonin receptor ligands in order to establish quantitative structure-affinity relationships. One hundred thirty-three compounds were considered: they were either collected from literature or newly synthesized in order to gain information about the less explored positions. To this end, various melatonin derivatives were prepared and their affinity for quail optic tecta melatonin receptor was tested. Compounds were aligned on the putative active conformation of melatonin proposed by our previously reported pharmacophore search, and their relative affinities were calculated from the displacement of 2-[125I]-iodomelatonin on different tissues expressing aMT receptors. Compounds were grouped into three sets according to their topology. Subset A: melatonin-like compounds; subset B: N-acyl-2-amino-8-methoxytetralins and related compounds; subset C:N-acyl-phenylalkylamines and related compounds. CoMFA models were derived for each set, using the steric, electrostatic, and lipophilic fields as structural descriptors; the PLS analyses were characterized by good statistical parameters, taking into account the heterogeneity of the binding data, obtained with different experimental protocols. From the CoMFA model for the melatonin-like compounds, besides the well-known positive effect of 2-substitution, a low steric tolerance for substituents in 1, 6, and 7, and a negative effect of electron-rich 4-substituents were observed; the information provided by the newly synthesized compounds was essential for these results. Moreover, a comprehensive model for the 133 compounds, accounting for a common alignment and a common mode of interaction at the melatonin receptor, was derived (Q2 = 0.769, R2 = 0.905). This model validates our previously reported pharmacophore search and offers a clear depiction of the structure-affinity relationships for the melatonin receptor ligands.
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Branchiccela B, Castelli L, Corona M, Díaz-Cetti S, Invernizzi C, Martínez de la Escalera G, Mendoza Y, Santos E, Silva C, Zunino P, Antúnez K. Impact of nutritional stress on the honeybee colony health. Sci Rep 2019; 9:10156. [PMID: 31300738 PMCID: PMC6626013 DOI: 10.1038/s41598-019-46453-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/20/2019] [Indexed: 11/09/2022] Open
Abstract
Honeybees Apis mellifera are important pollinators of wild plants and commercial crops. For more than a decade, high percentages of honeybee colony losses have been reported worldwide. Nutritional stress due to habitat depletion, infection by different pests and pathogens and pesticide exposure has been proposed as the major causes. In this study we analyzed how nutritional stress affects colony strength and health. Two groups of colonies were set in a Eucalyptus grandis plantation at the beginning of the flowering period (autumn), replicating a natural scenario with a nutritionally poor food source. While both groups of colonies had access to the pollen available in this plantation, one was supplemented with a polyfloral pollen patty during the entire flowering period. In the short-term, colonies under nutritional stress (which consumed mainly E. grandis pollen) showed higher infection level with Nosema spp. and lower brood and adult bee population, compared to supplemented colonies. On the other hand, these supplemented colonies showed higher infection level with RNA viruses although infection levels were low compared to countries were viral infections have negative impacts. Nutritional stress also had long-term colony effects, because bee population did not recover in spring, as in supplemented colonies did. In conclusion, nutritional stress and Nosema spp. infection had a severe impact on colony strength with consequences in both short and long-term.
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research-article |
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