A picture is worth a thousand words: using digital tools to visualise marine invertebrate diversity data along the coasts of Mozambique and São Tomé & Príncipe.

The amount of biological data available in online repositories is increasing at an exponential rate. However, data on marine invertebrate biodiversity resources from Mozambique and São Tomé and Príncipe are still sparse and scattered. Online repositories are useful instruments for biodiversity research, as they provide a fast access to data from different sources. The use of interactive platforms comprising web mapping are becoming more important, not only for the scientific community, but also for conservation managers, decision-makers and the general public as they allow data presentation in simple and understandable visual schemes. The main goal of this study was to create an interactive online digital map (hosted and available at MARINBIODIV Atlas), through the collection of data from various sources, to visualise marine invertebrate occurrences and distribution across different habitats, namely mangroves, seagrasses, corals and other coastal areas, in Mozambique and São Tomé and Príncipe. The acquired biodiversity data were managed and structured to be displayed as spatial data and to be disseminated using the geographic information system ArcGIS, where data can be accessed, filtered and mapped. The ArcGIS web mapping design tools were used to produce interactive maps to visualise marine invertebrate diversity information along the coasts of Mozambique and São Tomé and Príncipe, through different habitats, offering the foundation for analysing species incidence and allocation information. Understanding the spatial occurrences and distribution of marine invertebrates in both countries can provide a valuable baseline, regarding information and trends on their coastal marine biodiversity.

In vitro and in vivo assessment of heart-homing porous silicon nanoparticles.

Chronic heart failure, predominantly developed after myocardial infarction, is a leading cause of high mortality worldwide. As existing therapies have still limited success, natural and/or synthetic nanomaterials are emerging alternatives for the therapy of heart diseases. Therefore, we aimed to functionalize undecylenic acid thermally hydrocarbonized porous silicon nanoparticles (NPs) with different targeting peptides to improve the NP's accumulation in different cardiac cells (primary cardiomyocytes, non-myocytes, and H9c2 cardiomyoblasts), additionally to investigate the behavior of the heart-targeted NPs in vivo. The toxicity profiles of the NPs evaluated in the three heart-type cells showed low toxicity at concentrations up to 50 µg/mL. Qualitative and quantitative cellular uptake revealed a significant increase in the accumulation of atrial natriuretic peptide (ANP)-modified NPs in primary cardiomyocytes, non-myocytes and H9c2 cells, and in hypoxic primary cardiomyocytes and non-myocytes. Competitive uptake studies in primary cardiomyocytes showed the internalization of ANP-modified NPs takes place via the guanylate cyclase-A receptor. When a myocardial infarction rat model was induced by isoprenaline and the peptide-modified [(111)In]NPs administered intravenously, the targeting peptides, particularly peptide 2, improved the NPs' accumulation in the heart up to 3.0-fold, at 10 min. This study highlights the potential of these peptide-modified nanosystems for future applications in heart diseases.

The giant miniature endplate potentials frequency is increased in aged rats.

At the neuromuscular junction, spontaneous giant events (GMEPPs) are enhanced in different conditions when degenerative and/or remodeling processes take place, but no one investigated their incidence upon aging. In the present work, we evaluated evoked and spontaneous neuromuscular transmission events recorded from single muscle fibers. Phrenic-diaphragm preparations of 3-4, 12-16, 36-40 and 70-80 weeks old rat males were used. We found that the occurrence of GMEPPs significantly increases in aged rats. Moreover, in old rats the neuromuscular transmission was significantly impaired due to a significant decrease in the amplitude and quantal content of evoked endplate potentials. Interestingly, the number of observed EPPs failures were ∼ 3 times lower than the predicted value based on the quantal content. This discrepancy was not observed in infant or adult rats. The coincidence of a high GMEPPs frequency with a lower than expected EPPs failure rate suggests that GMEPPs events are needed to preserve effective neuromuscular transmission in aged animals.

Adenosine A2A receptors activation facilitates neuromuscular transmission in the pre-symptomatic phase of the SOD1(G93A) ALS mice, but not in the symptomatic phase.

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease leading to motor neuron dysfunction resulting in impairment of neuromuscular transmission. A2A adenosine receptors have already been considered as a potential therapeutical target for ALS but their neuromodulatory role at the neuromuscular junction in ALS remains to be clarified. In the present work, we evaluated the effects of A2A receptors on neuromuscular transmission of an animal model of ALS: SOD1(G93A) mice either in the pre-symptomatic (4-6 weeks old) or in the symptomatic (12-14 weeks old) stage. Electrophysiological experiments were performed obtaining intracellular recordings in Mg2+ paralyzed phrenic nerve-hemidiaphragm preparations. Endplate potentials (EPPs), quantal content (q. c.) of EPPs, miniature endplate potentials (MEPPs) and giant miniature endplate potential (GMEPPs) were recorded. In the pre-symptomatic phase of the disease (4-6 weeks old mice), the selective A2A receptor agonist, CGS 21680, significantly enhanced (p<0.05 Unpaired t-test) the mean amplitude and q.c. of EPPs, and the frequency of MEPPs and GMEPPs at SOD1(G93A) neuromuscular junctions, the effect being of higher magnitude (p<0.05, Unpaired t-test) than age-matched control littermates. On the contrary, in symptomatic mice (12-14 weeks old), CGS 21680 was devoid of effect on both the amplitude and q.c. of EPPs and the frequency of MEPPs and GMEPPs (p<0.05 Paired t-test). The results herein reported clearly document that at the neuromuscular junction of SOD1(G93A) mice there is an exacerbation of A2A receptor-mediated excitatory effects at the pre-symptomatic phase, whereas in the symptomatic phase A2A receptor activation is absent. The results thus suggest that A2A receptors function changes with ALS progression.

In vivo biocompatibility of porous silicon biomaterials for drug delivery to the heart.

Myocardial infarction (MI), commonly known as a heart attack, is the irreversible necrosis of heart muscle secondary to prolonged ischemia, which is an increasing problem in terms of morbidity, mortality and healthcare costs worldwide. Along with the idea to develop nanocarriers that efficiently deliver therapeutic agents to target the heart, in this study, we aimed to test the in vivo biocompatibility of different sizes of thermally hydrocarbonized porous silicon (THCPSi) microparticles and thermally oxidized porous silicon (TOPSi) micro and nanoparticles in the heart tissue. Despite the absence or low cytotoxicity, both particle types showed good in vivo biocompatibility, with no influence on hematological parameters and no considerable changes in cardiac function before and after MI. The local injection of THCPSi microparticles into the myocardium led to significant higher activation of inflammatory cytokine and fibrosis promoting genes compared to TOPSi micro and nanoparticles; however, both particles showed no significant effect on myocardial fibrosis at one week post-injection. Our results suggest that THCPSi and TOPSi micro and nanoparticles could be applied for cardiac delivery of therapeutic agents in the future, and the PSi biomaterials might serve as a promising platform for the specific treatment of heart diseases.

Early changes of neuromuscular transmission in the SOD1(G93A) mice model of ALS start long before motor symptoms onset.

Amyotrophic lateral sclerosis is characterized by a progressive degeneration of the corticospinal tract motor neurons. Growing evidence suggests that degeneration may begin at the distal axon proceeding in a dying-back pattern. It seemed therefore of interest to investigate synaptic transmission at the neuromuscular junction (NMJ) in pre- and symptomatic phases of the disease. Endplate potentials (EPPs), miniatures endplate potentials (MEPPs) and giant MEPPs (GMEPPs) were recorded from innervated diaphragm muscle fibers from 4-6 and 12-15 weeks-old SOD1(G93A) mice and non-transgenic aged-matched littermates (WT). In the pre-symptomatic phase, SOD1(G93A) mice exhibited a significant increase in the mean amplitude of EPPs together with an increase in the mean quantal content of EPPs, suggesting that more acetylcholine is being released into the synaptic cleft. SOD1(G93A) mice presented a higher frequency of GMEPPs, suggestive of intracellular Ca(2+) deregulation in nerve terminals. The increase in the mean amplitude of MEPPs and the decreased mean rise-time of MEPPs in SOD1(G93A) mice point to post-synaptic related changes. In the symptomatic phase, electrophysiological data showed evidence for two NMJ groups in SOD1(G93A) mice: SOD1a and SOD1b. SOD1a group presented reduced mean amplitude of both EPPs and MEPPs. The mean rise-time of MEPPs was increased, when compared to WT and to SOD1b group, indicating impairments in the neuromuscular transmission. In contrast, the neuromuscular transmission of SOD1b group was not different from age-matched WT nor pre-symptomatic SOD1(G93A) mice, being somehow in between both groups. Altogether these results show that the neuromuscular transmission of SOD1(G93A) mice is enhanced in the pre-symptomatic phase. In the symptomatic phase our results are consistent with the hypothesis that the diaphragm of SOD1(G93A) mice is undergoing cycles of denervation/re-innervation supported by mixed neuromuscular junction populations. These early changes in the neuromuscular transmission of SOD1(G93A) mice suggest that the ALS associated events start long before symptoms onset.

Neuromuscular transmission modulation by adenosine upon aging.

In infant rats adenosine A(2A) receptor-mediated modulation of neuromuscular transmission predominates over A1 receptor-mediated neuromodulation. We investigated whether aging affects this A(2A)/A(1) receptor balance. Evoked (EPPs) and miniature end plate potentials (MEPPs) were recorded from single fibers of (weeks-old) infant (3-4), young adult (12-16), older (36-38), and aged (80-90) male rat-diaphragm. The non A1/A(2A) selective agonist, 2-chloroadenosine (CADO; 30 nM) and the adenosine kinase inhibitor, iodotubericidin (ITU; 10 µM) increased mean amplitude and quantal content of EPPs in infant, young adult, and older adult rats, but not in aged rats. The facilitatory effects were prevented by the A(2A) receptor antagonist, ZM241385 (50 nM) and mimicked by the A(2A) receptor agonist, CGS21680 (10 nM). The A1 receptor agonist, 6-cyclopentyladenosine (CPA; 100 nM), decreased EPPs amplitude in all age groups. It is concluded that aging differently influences adenosine A1 receptor and A(2A) receptor-mediated presynaptic modulation of neuromuscular transmission, so that the facilitatory influence decreases upon aging, whereas the inhibitory influence remains unchanged in aged animals. The reduction of adenosine A(2A) receptors upon aging may contribute to the age-related changes in neuromuscular function.

Predominance of adenosine excitatory over inhibitory effects on transmission at the neuromuscular junction of infant rats.

Adenosine-induced modulation of neuromuscular transmission in young (3-4-week-old) rats was evaluated. Inhibition of adenosine kinase with iodotubercidin (ITU; 10 microM), which is known to induce adenosine release, enhanced the amplitude of evoked end-plate potentials (EPPs) recorded from innervated diaphragm muscle fibers. This facilitatory effect was transformed into an inhibitory one upon blockade of adenosine A(2A) receptors with 4-(2-[7-amino-2-(2-furly)[1,2,4]triazolo[2,3-a][1,3,5]triazin5ylamino] ethyl) phenol (ZM 241385) (50 nM); further blockade of adenosine A(1) receptors with the selective antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; 10 nM) abolished that inhibition. Adenosine or 2-chloroadenosine (CADO), at submicromolar concentrations, increased the amplitude and the quantal content of EPPs, whereas at low micromolar concentrations they decreased EPP amplitude. Blockade of A(1) receptors with DPCPX (10 nM) prevented both excitatory and inhibitory effects, whereas blockade of A(2A) receptors with ZM241385 (50 nM) prevented only the excitatory effects. DPCPX and ZM241385 also prevented the excitatory effect of the selective A(2A) receptor agonist 2-[p-(2-carboxyethyl) phenethylamino]-5'-N-ethylcarboxamido adenosine hydrochloride (CGS 21680; 10 nM). CADO (30 nM) also increased neuromuscular transmission in adult (12-16-week-old) rats. It is suggested that at the motor nerve endings, low extracellular concentrations of adenosine activate both A(2A) and A(1) receptors, but activation of A(2A) receptors predominates over A(1) receptors; the activity of A(2A) receptors might, however, require coactivation of A(1) receptors. This facilitatory action of low concentrations of extracellular adenosine upon acetylcholine release may be particularly relevant at developing neuromuscular junctions, where subtle changes in synaptic levels of acetylcholine might influence synaptic stabilization.