274 research outputs found
Superficial sedimentary stocks and sources of carbon and nitrogen in coastal vegetated assemblages along a flow gradient
Coastal vegetated ecosystems are major organic carbon (OC) and total nitrogen (TN) sinks, but the mechanisms that regulate their spatial variability need to be better understood. Here we assessed how superficial sedimentary OC and TN within intertidal vegetated assemblages (saltmarsh and seagrass) vary along a flow gradient, which is a major driver of sediment grain size, and thus of organic matter (OM) content. A significant relationship between flow current velocity and OC and TN stocks in the seagrass was found, but not in the saltmarsh. OC and TN stocks of the saltmarsh were larger than the seagrass, even though that habitat experiences shorter hydroperiods. Mixing models revealed that OM sources also varied along the flow gradient within the seagrass, but not in the saltmarsh, showing increasing contributions of microphytobenthos (17-32%) and decreasing contributions of POM (45-35%). As well, OM sources varied vertically as microphytobenthos contribution was highest at the higher intertidal saltmarsh (48%), but not POM (39%). Macroalgae, seagrass and saltmarsh showed low contributions. Local trade-offs between flow current velocities, hydroperiod and structural complexity of vegetation must be considered, at both horizontal and vertical (elevation) spatial dimensions, for better estimates of blue carbon and nitrogen in coastal ecosystems.Foundation of Science and Technology of Portugal (FCT)
PTDC/MAR-EST/3223/2014
UID/Multi/04326/2013
FCT UID/MAR/00350/2018
SFRH/BPD/119344/2016info:eu-repo/semantics/publishedVersio
Vertical intertidal variation of organic matter stocks and patterns of sediment deposition in a mesotidal coastal wetland
Tidal coastal wetlands, common home to seagrass and salt marshes, are relevant carbon sinks due to their high
capacity to accumulate and store organic carbon in their sediments. Recent studies demonstrated that the spatial
variability of this organic carbon within the same wetland system can be significant. Some of the environmental
drivers of this spatial variability remain understudied and the selection of the most relevant ones can be context
dependent. Here we investigated the role of bed elevation, hydrodynamics, and habitat type (salt marsh and
seagrass) on the organic matter (OM) net deposition-resuspension rate and superficial sedimentary stocks (top 5
cm) at the tidal wetlands of the Ria Formosa, a mesotidal coastal lagoon in South Portugal. Results showed that
two vectors of spatial variation need to be considered to describe the intertidal sedimentary OM stocks: the bed
elevation that imposes a decrease of the hydroperiod and thus the change of habitat from the lower seagrass
Z. noltei to the upper saltmarsh S. maritimus, and the horizontal spatial variation along the secondary channels of
the lagoon that imposes a decrease in the current flow velocity magnitude. The multiple linear regression analyses, using data from 40 sampling points, explained 59% of the variation of the superficial sedimentary stocks
of OM in salt marshes and seagrasses of the Ria Formosa lagoon and revealed that stocks generally decrease with
elevation, yet with variation among sites and habitats. It was also found that the decrease of the OM net
deposition-resuspension rate with bed elevation was exponential. Our study emphasizes the importance of
considering multiple environmental drivers and spatial variation for regional estimations of organic matter (and
organic carbon) sedimentary stocks in coastal wetlands.info:eu-repo/semantics/publishedVersio
Carbon and nitrogen stocks and burial rates in intertidal vegetated habitats of a Mesotidal coastal lagoon
Coastal vegetated ecosystems such as saltmarshes
and seagrasses are important sinks of organic carbon (OC) and total nitrogen (TN), with large global
and local variability, driven by the confluence of
many physical and ecological factors. Here we
show that sedimentary OC and TN stocks of intertidal saltmarsh (Sporobolus maritimus) and seagrass
(Zostera noltei) habitats increased between two- and
fourfold along a decreasing flow velocity gradient
in Ria Formosa lagoon (south Portugal). A similar
twofold increase was also observed for OC and TN
burial rates of S. maritimus and of almost one order
of magnitude for Z. noltei. Stable isotope mixing models identify allochthonous particulate organic
matter as the main source to the sedimentary pools
in both habitats (39–68%). This is the second estimate of OC stocks and the first of OC burial rates in
Z. noltei, a small, fast-growing species that is widely
distributed in Europe (41,000 ha) and which area is
presently expanding (8600 ha in 2000s). Its wide
range of OC stocks (29–99 Mg ha-1
) and burial
rates (15–122 g m2 y-1
) observed in Ria Formosa
highlight the importance of investigating the drivers of such variability to develop global blue carbon models. The TN stocks (7–11 Mg ha-1
) and
burial rates (2–4 g m-2 y-1
) of Z. noltei were generally higher than seagrasses elsewhere. The OC
and TN stocks (29–101 and 3–11 Mg ha-1
, respectively) and burial rates (19–39 and 3–5 g m-2 y-1
)
in S. maritimus saltmarshes are generally lower than
those located in estuaries subjected to larger accumulation of terrestrial organic matter.DL57/2016/CP1361/CT0002; MinECo, MDM2015-0552info:eu-repo/semantics/publishedVersio
The role of primary pharmacological therapy in acromegaly
BACKGROUND AND OBJECTIVES: Primary pharmacological therapy may be the only viable treatment option for many patients with acromegaly, especially those presenting with advanced disease with large inoperable tumors. Long-acting somatostatin analogs are currently the first-line treatment of choice in this setting, where they provide biochemical control and reduce tumor size in a significant proportion of patients. We herein present a brief overview of the role of primary pharmacological therapy in the treatment of acromegaly within the context of Latin America and support this with a representative case study. CASE DESCRIPTION: A 20 year old male presented with clinical and biochemical evidence of acromegaly. The glucose-suppressed growth hormone (GH) was 5.3 μg/L, his insulin-like growth factor-1(IGF-1) was 3.5 times the ULN and serum prolactin greater than 4,000 μg/L. Pituitary MRI revealed a large and invasive mass, extending superiorly into the optic chiasm and laterally into the left cavernous sinus. He was treated with a combination of octreotide and cabergoline with remarkable clinical improvement, normalization of GH and IGF-1 values and striking shrinkage of the adenoma. CONCLUSION: This case illustrates how effective the pharmacological therapy of acromegaly can be and yet at the same time, raises several important issues such as the need for life-long treatment with costly medications such as the somatostatin analogs. Access to these agents may be limited in regions where resources are restricted and clinicians face challenges in order to make the most efficient use of available options
Onset of microglial entry into developing quail retina coincides with increased expression of active caspase-3 and is mediated by extracellular ATP and UDP
Microglial cell precursors located in the area of the base of the pecten and the optic nerve head (BP/ONH) start to enter the retina of quail embryos at the 7 th day of incubation (E7), subsequently colonizing the entire retina by central-to-peripheral tangential migration, as previously shown by our group. The present study demonstrates a precise chronological coincidence of the onset of microglial cell entry into the retina with a striking increase in death of retinal cells, as revealed by their active caspase-3 expression and TUNEL staining, in regions dorsal to the BP/ONH area, suggesting that dying retinal cells would contribute to the microglial cell inflow into the retina. However, the molecular mechanisms involved in this inflow are currently unclear. Extracellular nucleotides, such as ATP and UDP, have previously been shown to favor migration of microglia towards brain injuries because they are released by apoptotic cells and stimulate both chemotaxis and chemokinesis in microglial cells via signaling through purinergic receptors. Hence, we tested here the hypothesis that ATP and UDP play a role in the entry and migration of microglial precursors into the developing retina. For this purpose, we used an experimental model system based on organotypic cultures of E6.5 quail embryo retina explants, which mimics the entry and migration of microglial precursors in the in situ developing retina. Inhibition of purinergic signaling by treating retina explants with either apyrase, a nucleotide-hydrolyzing enzyme, or suramin, a broad spectrum antagonist of purinergic receptors, significantly prevents the entry of microglial cells into the retina. In addition, treatment of retina explants with either exogenous ATP or UDP results in significantly increased numbers of microglial cells entering the retina. In light of these findings, we conclude that purinergic signaling by extracellular ATP and UDP is necessary for the entry and migration of microglial cells into the embryonic retina by inducing chemokinesis in these cells
Fungal and ciliate protozoa are the main rumen microbes associated with methane emissions in dairy cattle
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Departamento de Mejora Genetica AnimalMitigating the effects of global warming has become the main challenge for humanity in recent decades. Livestock farming contributes to greenhouse gas emissions, with an important output of methane from enteric fermentation processes, mostly in ruminants. Because ruminal microbiota is directly involved in digestive fermentation processes and methane biosynthesis, understanding the ecological relationships between rumen microorganisms and their active metabolic pathways is essential for reducing emissions. This study analysed whole rumen metagenome using long reads and considering its compositional nature in order to disentangle the role of rumen microbes in methane emissions.This research was financed by RTA2015-00022-C03-02 (METALGEN) project from the National Plan of Research, Development and Innovation 2013–2020 and the Department of Economic Development and Competitiveness (Madrid, Spain). A.L.G. was funded by FPI-INIA grant with reference FPI-SGIT2016-06.Peer reviewe
Targeting ribosomal G-quadruplexes with naphthalene-diimides as RNA polymerase I inhibitors for colorectal cancer treatment
Guanine quadruplexes (G4s) are non-canonical nucleic acid structures commonly found in regulatory
genomic regions. G4 targeting has emerged as a therapeutic approach in cancer. We have screened naph thalene-diimides (NDIs), a class of G4 ligands, in a cellular model of colorectal cancer (CRC). Here, we identify
the leading compound T5 with a potent and selective inhibition of cell growth by high-affinity binding to G4s in
ribosomal DNA, impairing RNA polymerase I (Pol I) elongation. Consequently, T5 induces a rapid inhibition of
Pol I transcription, nucleolus disruption, proteasome-dependent Pol I catalytic subunit A degradation and
autophagy. Moreover, we attribute the higher selectivity of carbohydrate-conjugated T5 for tumoral cells
to its preferential uptake through the overexpressed glucose transporter 1. Finally, we succinctly demon strate that T5 could be explored as a therapeutic agent in a patient cohort with CRC. Therefore, we report
a mode of action for these NDIs involving ribosomal G4 targeting
Clinical validation of the EndoPredict test in node-positive, chemotherapy-treated ER+/HER2− breast cancer patients: results from the GEICAM 9906 trial
INTRODUCTION: EndoPredict (EP) is an RNA-based multigene test that predicts the likelihood of distant recurrence in patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2–negative (HER2−) breast cancer (BC) who are being treated with adjuvant endocrine therapy. Herein we report the prospective-retrospective clinical validation of EP in the node-positive, chemotherapy-treated, ER+/HER2− BC patients in the GEICAM 9906 trial. METHODS: The patients (N = 1,246) were treated either with six cycles of fluorouracil, epirubicin and cyclophosphamide (FEC) or with four cycles of FEC followed by eight weekly courses of paclitaxel (FEC-P), as well as with endocrine therapy if they had hormone receptor–positive disease. The patients were assigned to EP risk categories (low or high) according to prespecified cutoff levels. The primary endpoint in the clinical validation of EP was distant metastasis-free survival (MFS). Metastasis rates were estimated using the Kaplan-Meier method, and multivariate analysis was performed using Cox regression. RESULTS: The molecular EP score and the combined molecular and clinical EPclin score were successfully determined in 555 ER+/HER2− tumors from the 800 available samples in the GEICAM 9906 trial. On the basis of the EP, 25% of patients (n = 141) were classified as low risk. MFS was 93% in the low-risk group and 70% in the high-risk group (absolute risk reduction = 23%, hazard ratio (HR) = 4.8, 95% confidence interval (CI) = 2.5 to 9.5; P < 0.0001). Multivariate analysis showed that, in this ER+/HER2− cohort, EP results are an independent prognostic parameter after adjustment for age, grade, lymph node status, tumor size, treatment arm, ER and progesterone receptor (PR) status and proliferation index (Ki67). Using the predefined EPclin score, 13% of patients (n = 74) were assigned to the low-risk group, who had excellent outcomes and no distant recurrence events (absolute risk reduction vs high-risk group = 28%; P < 0.0001). Furthermore, EP was prognostic in premenopausal patients (HR = 6.7, 95% CI = 2.4 to 18.3; P = 0.0002) and postmenopausal patients (HR = 3.3, 95% CI = 1.3 to 8.5; P = 0.0109). There were no statistically significant differences in MFS between treatment arms (FEC vs FEC-P) in either the high- or low-risk groups. The interaction test results between the chemotherapy arm and the EP score were not significant. CONCLUSIONS: EP is an independent prognostic parameter in node-positive, ER+/HER2− BC patients treated with adjuvant chemotherapy followed by hormone therapy. EP did not predict a greater efficacy of FEC-P compared to FEC alone
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