Response to Interpreting the results of oceanic mesoscale enrichment experiments: Caveats and lessons from limnology and coastal ecology

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Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

8 pages, 3 figures, 2 tables, supplementary material http://dx.doi.org/10.3389/fmicb.2015.01566Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budgetThis is a contribution to projects RODA (CTM2004-06842-CO3-02), and ATOS (POL2006-00550/CTM) projects, funded by the Spanish Ministry of Science and Innovation and project THRESHOLDS funded by the 6 Framework Programme of the European Union. JA was supported by a “Ramón y Cajal” research fellowship from the Spanish Government.Peer Reviewe

Relaxant effects of Peperomia hispidula (Sw.) A. Dietr. on isolated rat tracheal rings

Peperomia hispidula (Sw.) A. Dietr. is used in Mexican traditional medicine for treating respiratory illnesses such as asthma. The latter disorder results from an excessive and inappropriate constriction of airway smooth muscle. The aim of the present study was to evaluate the relaxant activity of P. hispidula on isolated rat tracheal rings contracted with carbachol. The methyleugenol was identified as the main active constituent in the dichloromethane extract. To explore the possible mechanism of action, concentration-response curves were constructed in the presence and absence of propranolol (3 μM), indomethacin (10 μM), glibenclamide (1 μM), and L-NAME (300μM), finding that neither reduced methyleugenol-induced smooth muscle relaxation. In conclusion, P. hispidula herein displayed relaxant activity on rat tracheal rings. The effect of methyleugenol, was probably not related to the activation of β2-adrenoceptors, prostaglandins, K+ATP channels or nitric oxide

Response to Comment on >dilution limits dissolved organic carbon utilization in the deep ocean>

Our recent finding that dilution limits dissolved organic carbon (DOC) utilization in the deep ocean has been criticized based on the common misconception that lability equates to rapid and complete utilization. Even when considering the redefinition of recalcitrant DOC recently proposed by Jiao et al., the dilution hypothesis best explains our experimental observations.This is a contribution to the MALASPINA Expedition 2010 project, funded by the CONSOLIDER-Ingenio 2010 program of the Spanish Ministry of Economy and Competitiveness (ref. CSD2008-00077)Peer Reviewe

Actividad relajante de Hyptis suaveolens en anillos aislados de tráquea de cobayo

El asma es una enfermedad crónica cuya sintomatología incluye la dificultad respiratoria, que se debe a la restricción del flujo de aire. Esto se atribuye a la contracción del músculo liso bronquial por diversos mediadores inflamatorios.  Desafortunadamente, en la mayoría de los pacientes las terapias existentes no han logrado un control adecuado de la sintomatología, por lo que es necesaria la búsqueda de nuevas opciones.  Hyptis suaveolens es utilizada en el estado de Chiapas, México, para tratar el asma, sin embargo, esta actividad no ha sido corroborada científicamente. Por lo que el objetivo de la presente contribución fue determinar la actividad relajante de Hyptis suaveolens en el modelo de anillos aislados de tráquea de cobayo. Los extractos de hexano, diclorometano y metanol de la planta se prepararon por maceración. El extracto de mayor actividad se separó por cromatografía en columna para encontrar la fracción más activa. Se determinó la participación de los receptores β2 adrenérgicos y muscarínicos, mediante curvas concentración-respuesta a partir de los siguientes tratamientos: la subfracción activa de Hyptis suaveolens (56-177 µg/mL) e isoproterenol (3-170 µM) en ausencia y presencia de propranolol (0.3 µM), y carbacol (1x10-16-0.01 M) en ausencia y presencia de la subfracción activa (100 y 177 µg/mL) o de atropina (0.3 y 3 µM). El extracto de diclorometano fue el más activo (p<0.05), y su subfracción más activa (F4´) tuvo una CE50 de 91.19 ± 1.83 µg/mL. El efecto relajante de F4´ no fue inhibido por propranolol. F4´ se comportó como un antagonista competitivo de los receptores muscarínicos (p<0.01).  En conclusión, Hyptis suaveolens ejerce actividad relajante sobre anillos aislados de tráquea de cobayo. Una subfracción activa del extracto de diclorometano actuó como antagonista competitivo sobre los receptores muscarínicos, pero los receptores β2 adrenérgicos no participaron en su mecanismo de acción

Neurexin and neuroligin genes in Alzheimer's disease

Póster presentado en la 11th International Conference on Alzheimer's & Parkinson's Diseases, celebrada en Florencia del 6 al 10 de marzo de 2013.-- Alzheimers Disease Neuroimaging Inititive[Objectives] The interaction between neurexins and neuroligins promotes the formation of functional synaptic structures. Recently, it has been reported that neurexins and neuroligins are proteolytically processed by presenilins at synapses. Based on this interaction and the role of presenilins in familial Alzheimer's disease (AD), we hypothesized that dysfunction of the neuroligin-neurexin pathway might be associated with AD.[Methods] To explore this hypothesis we carried out a meta-analysis of five genome-wide association studies (GWAS) comprising 1256 SNPs in the NRXN1, NRXN2, NRXN3 and NLGN1 genes (3009 cases and 3006 control individuals) using PLINK software.[Results] We identified a marker in the NRXN3 gene (rs17757879) that showed a consistent protective effect in all GWAS, however the statistical significance obtained did not resist multiple testing corrections (OR=0.851, p=0.002). Nonetheless, gender analysis revealed that this effect was restricted to males. A replication study with SNP rs17757879 in a Spanish population (1785 cases and 1634 controls) confirmed this observation (OR=0.752, C.I.=0.570-0.991, p=0.042).[Conclusions] We conclude that NRXN3 might have a role in susceptibility to AD in males (rs17757879, OR=0.742, 95% C.I.=0.632-0.872, p=0.00028, final meta-analysis).Peer Reviewe

Genetic study of neurexin and neuroligin genes in Alzheimer's disease

The interaction between neurexins and neuroligins promotes the formation of functional synaptic structures. Recently, it has been reported that neurexins and neuroligins are proteolytically processed by presenilins at synapses. Based on this interaction and the role of presenilins in familial Alzheimer's disease (AD), we hypothesized that dysfunction of the neuroligin-neurexin pathway might be associated with AD. To explore this hypothesis, we carried out a meta-analysis of five genome-wide association studies (GWAS) comprising 1, 256 SNPs in the NRXN1, NRXN2, NRXN3, and NLGN1 genes (3,009 cases and 3,006 control individuals). We identified a marker in the NRXN3 gene (rs17757879) that showed a consistent protective effect in all GWAS, however, the statistical significance obtained did not resist multiple testing corrections (OR = 0.851, p = 0.002). Nonetheless, gender analysis revealed that this effect was restricted to males. A combined meta-analysis of the former five GWAS together with a replication Spanish sample consisting of 1,785 cases and 1,634 controls confirmed this observation (rs17757879, OR = 0.742, 95% CI = 0.632-0.872, p = 0.00028, final meta-analysis). We conclude that NRXN3 might have a role in susceptibility to AD in males.Peer Reviewe

Assessing the role of the TREM2 p.R47H variant as a risk factor for Alzheimer's disease and frontotemporal dementia

4 páginas, 1 figura, a tabla. Los autores pertenecen a The dementia genetic Spanish consortium (DEGESCO).A non-synonymous genetic rare variant, rs75932628-T (p.R47H), in the TREM2 gene has recently been reported to be a strong genetic risk factor for Alzheimer's disease (AD). Also, rare recessive mutations have been associated with frontotemporal dementia (FTD). We aimed to investigate the role of p.R47H variant in AD and FTD through a multi-center study comprising 3,172 AD and 682 FTD patients and 2,169 healthy controls from Spain. We found that 0.6% of AD cases carried this variant compared to 0.1% of controls (odds ratio [OR]=4.12, 95% confidence interval [CI]: 1.21-14.00, P=0.014). A meta-analysis comprising 32,598 subjects from four previous studies demonstrated the large effect of the p.R47H variant in AD risk (OR=4.11, 95% CI: 2.99-5.68, P=5.27x10-18). We did not find an association between p.R47H and age of onset of AD or family history of dementia. Finally, none of the FTD patients harbored this genetic variant. These data strongly support the important role of p.R47H in AD risk and suggest that this rare genetic variant is not related to FTD.This study was supported by grants from Instituto de Salud Carlos III (PI12/01311 and 12/00013), grants from the Ministry of Science (SAF2010-15558, SAF2009-10434), Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, Spain), Consolider (CSD2010-00045), and the Department of Health of the Government of Navarra (refs. 13085 and 3/2008). CR held during the period 2009-2013 a “Torres Quevedo” fellowship from the Spanish Ministry of Science and Technology, co-financed by the European Social Fund. Fundació ACE researchers are indebted to Trinitat Port-Carbó and her family who are supporting Fundació ACE scientific programs.Peer reviewe