Bacterioplankton Community Shifts during a Spring Bloom of Aphanizomenon gracile and Sphaerospermopsis aphanizomenoides at a Temperate Shallow Lake

Climate change is enhancing the frequency of cyanobacterial blooms not only during summer but also in spring and autumn, leading to increased ecological impacts. The bacterioplankton community composition (BCC), in particular, is deeply affected by these blooms, although at the same time BCC can also play important roles in blooms’ dynamics. However, more information is still needed regarding BCC during species-specific cyanobacterial blooms. The goal of this study was to assess BCC succession in a hypereutrophic shallow lake (Vela Lake, Portugal) during a warm spring using a metagenomic approach to provide a glimpse of the changes these communities experience during the dominance of Aphanizomenon-like bloom-forming species. BCC shifts were studied using 16S rRNA gene metabarcoding and multivariate analyses. A total of 875 operational taxonomic units (OTUs) were retrieved from samples. In early spring, the dominant taxa belonged to Proteobacteria (mainly Alphaproteobacteria—Rickettsiales) and Bacteroidetes (Saprospirales, Flavobacteriales and Sphingobacteriales). However, at the end of May, a bloom co-dominated by cyanobacterial populations of Aphanizomenon gracile, Sphaerospermopsis aphanizomenoides and Synechococcus sp. developed and persisted until the end of spring. This led to a major BCC shift favouring the prevalence of Alphaproteobacteria (Rickettsiales and also Rhizobiales, Caulobacteriales and Rhodospirillales) and Bacteroidetes (Saprospirales, followed by Flavobacteriales and Sphingobacteriales). These results contribute to the knowledge of BCC dynamics during species-specific cyanobacterial blooms, showing that BCC is strongly affected (directly or indirectly) by Aphanizomenon-Sphaerospermopsis blooms.publishe

Derivados amínicos do LCC como inibidores da acetilcolinesterase, processos para sua obtenção, composições farmacêuticas contendo os mesmos e aplicações

DepositadaDescreve certos compostos e seus sais, solvatos e/ou isômeros farmaceuticamente aceitáveis. Os derivados fenólicos do LCC constituem sistema biofórico natural compreendendo características eletrônicas e hidrofóbicas, as quais são requisitos estruturais relevantes ao reconhecimento molecular pela enzima acetilcolinesterase (AChE). O desenvolvimento de derivados semissintéticos contendo subunidades farmacofóricas apresentaram relevante atividade anticolinesterásica, sendo estes compostos úteis ao tratamento da doença de Alzheimer

The Fluorescence Detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

Reconstruction of inclined air showers detected with the Pierre Auger Observatory

We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than $60^\circ$ detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analyses including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.Comment: 27 pages, 19 figures, accepted for publication in Journal of Cosmology and Astroparticle Physics (JCAP

Magnitude profiles derived from WSA and TEA.

<p>N10avR total magnitudes (TMags) were calculated by quantifying and summing magnitudes of all events for each response of intact (A1) and regenerating (A2) sural nerves using WSA (black) and TEA (grey). TMags derived from WSA were amplitude-corrected (dashed) by multiplying the TMag^WSA by a constant (indicated) derived from the ratio of [mean TMag^TEA]/[mean TMag^WSA] (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136992#sec002" target="_blank">Materials and Methods</a>) evoked from the strongest stimulus pulse (1.4 mA). Magnitude profiles were also derived from M5avR TMags for intact (B1) and regenerating (B2) nerves. Similarly, TMag^WSA of M5avRs were amplitude-corrected (dashed) by multiplying by a constant (indicated) based on the ratio of mean total magnitudes with the greatest inter-pulse interval (10 ms).</p

Generation of template signals used for waveform similarity analysis.

<p>Sural nerve (A) and tibial muscle EMG (B) template signals were generated from the intact side (left) of rats. The mean for each template was derived after individual responses were temporally aligned to the primary positive peak (arrows). See text for further details.</p

Effect of WSA event detection threshold levels on the number of identified events.

<p>Empirically derived functions were used to determine an ideal detection threshold. A demonstrates the mean number of events detected by WSA from N10avRs evoked from injured sciatic nerves by a 0.7 mA stimulus, as a function of the detection threshold level. The detection threshold level indicates the multiple of standard deviations (refer to red line in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136992#pone.0136992.g002" target="_blank">Fig 2B2</a> showing one standard deviation) that the mean (black line, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136992#pone.0136992.g002" target="_blank">Fig 2B2</a>) of 3 repeated N10avRs had to be greater than, in order to detect an event using WSA. The fuzzy line represents the mean and SEM (6.5 ± 0.6) of the number of events detected by TEA for the same responses. Throughout the study, 2.0× was chosen as the standard detection threshold level for N10avRs, as this level detects a number of events not significantly different to that detected by TEA. B demonstrates the mean number of events detected from M5avRs evoked from injured sciatic nerves by a paired stimulus as a function of background noise level. The paired stimulus was 0.7 mA with an inter-pulse interval of 1 ms. Background noise was calculated from the mean absolute amplitude of the last 17 ms of the sweep, a region where no signal was present. The detection threshold level indicates the threshold based on a multiple of background noise. The grey line indicates the ideal level of event detection, i.e. where the number of events = 1. For <i>in vivo</i> experiments, 12× the background noise level was chosen as the standard detection threshold level for M5avRs.</p

Latency profiles derived by WSA and TEA.

<p>The latency to the peak of the first event of N10avRs (A1, intact side; A2, regenerating side) and the latency to the peak of M5avRs (B1, intact side; B2, regenerating side) were measured using the temporal location of best fit between the event and its respective template signals (WSA), and compared with the latency of the peak of each respective event (TEA). There was no significant difference in the latencies derived from WSA and TEA. Inter-pulse interval = time interval between the conditioning and testing pulses (refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136992#pone.0136992.g004" target="_blank">Fig 4</a>). Abbreviations: WSA, waveform similarity analysis; TEA, trained eye analysis.</p

Simulation experiment of WSA performance under conditions of template distortion.

<p>Simulated signals generated by adding three multiples (0.5×, 1.0× and 2.0×) of a signal of interest (A, true signal) to noise (B), were used to derive a signal for analysis (C, total). WSA was applied using three templates; the correct one identical to 1.0× the true signal (C, blue), a template with double (C, red) and half (C, green) the frequency content of the correct template. Latency-corrected WSA outputs calculated from the cross-correlation sequence (xycorr) are shown (D) for each template (WSA1, blue, output with correct template; WSA2, red, template with double the correct frequency; WSA3, green, template with half the correct frequency). Overlayed to WSA outputs is the true signal, with the positive and negative peaks indicated (black dots) that reports the true peak-to-peak measurements for comparing the performance of WSA and TEA. Peak detection threshold at >4× the standard deviation of the first 400 ms of each respective WSA output was used to automate peak detection (D, blue, red and green dots indicate peaks for WSA1, WSA2 and WSA3 respectively). The latency (E) and Magnitude (F) errors are shown for WSA performed by each template (following latency and amplitude correction respectively) and TEA for the 6 samples of each signal. The black line indicates zero error; data expressed as mean ± SEM.</p