[Classical nephroprotection: Renin angiotensin aldosterone system inhibitors]

The role of the renin angiotensin aldosterone system (RAAS) in the pathophysiology of hypertension, cardiovascular disease and kidney disease has been known for years. RAAS inhibitors have been the mainstay of chronic kidney disease (CKD) treatment. Studies have shown that therapy with angiotensin-converting enzyme inhibitors (ACE inhibitors) or angiotensinII receptor blockers (ARBs) reduce the excretion of albuminuria and slow the progression of kidney disease in patients with and without diabetes. In clinical practice, RAAS inhibitors are recommended as the antihypertensive of choice in patients with CKD and albuminuria with or without diabetes. In addition, they have demonstrated cardiovascular benefits beyond blood pressure control. The use of RAAS inhibitors in non-proteinuric nephropathy and advanced CKD is not without controversy. Double blockade of the RAAS is contraindicated. On the other hand, it is essential to know how to titrate doses and avoid side effects, mainly hyperkalaemia.

Microplastics and other anthropogenic particles in Antarctica: Using penguins as biological samplers

Microplastics (< 5 mm in size) are known to be widespread in the marine environment but are still poorly studied in Polar Regions, particularly in the Antarctic. As penguins have a wide distribution around Antarctica, three congeneric species: Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarcticus) and gentoo penguins (Pygoscelis papua) were selected to evaluate the occurrence of microplastics across the Antarctic Peninsula and Scotia Sea. Scat samples (used as a proxy of ingestion), were collected from breeding colonies over seven seasons between 2006 and 2016. Antarctic krill (Euphausia superba), present in scat samples, contributed 85%, 66% and 54% of the diet in terms of frequency of occurrence to the diet of Adélie, gentoo and chinstrap penguins, respectively. Microplastics were found in 15%, 28% and 29% scats of Adélie, chinstrap and gentoo penguin respectively. A total of 92 particles were extracted from the scats (n = 317) and 32% (n = 29) were chemically identified via micro-Fourier Transform Infrared Spectroscopy (μ-FTIR). From all the particles extracted, 35% were identified as microplastics, particularly polyethylene (80%) and polyester (10%). It was not possible to ascertain the identification of the remaining 10% of samples. Other anthropogenic particles were identified in 55% of samples, identified as cellulose fibres. The results show a similar frequency of occurrence of particles across all colonies, suggesting there is no particular point source for microplastic pollution in the Scotia Sea. Additionally, no clear temporal variation in the number of microplastics in penguins was observed. Overall, this study reveals the presence of microplastics across Antarctica, in three penguin species and offers evidence of other anthropogenic particles in high numbers. Further research is needed to better understand the spatio-temporal dynamics, fate and effect of microplastics on these ecosystems, and improve plastic pollution policies in Antarctica.

Microplastics in wild fish from North East Atlantic Ocean and its potential for causing neurotoxic effects, lipid oxidative damage, and human health risks associated with ingestion exposure

Microplastics (MP) pollution has received increased attention over the last few years. However, while the number of studies documentating the ingestion of microplastics by fish has increased, fewer studies have addressed the toxicological effects derived from the ingestion of these small items in wild conditions. Here, MP contamination and effect biomarkers were investigated in three commercially important fish species from the North East Atlantic Ocean. From the 150 analysed fish (50 per species), 49 % had MP. In fish from the 3 species, MP in the gastrointestinal tract, gills and dorsal muscle were found. Fish with MP had significantly (p ≤ 0.05) higher lipid peroxidation levels in the brain, gills and dorsal muscle, and increased brain acetylcholinesterase activity than fish where no MP were found. These results suggest lipid oxidative damage in gills and muscle, and neurotoxicity through lipid oxidative damage and acetylcholinesterase induction in relation to MP and/or MP-associated chemicals exposure. From the 150 fish analysed, 32 % had MP in dorsal muscle, with a total mean (± SD) of 0.054 ± 0.099 MP items/g. Based on this mean and on EFSA recommendation for fish consumption by adults or the general population, human consumers of Dicentrachus labrax, Trachurus trachurus, Scomber colias may intake 842 MP items/year from fish consumption only. Based on the mean of MP in fish muscle and data (EUMOFA, NOAA) of fish consumption per capita in selected European and American countries, the estimated intake of microplastics through fish consumption ranged from 518 to 3078 MP items/year/capita. Considering that fish consumption is only one of the routes of human exposure to microplastics, this study and others in the literature emphasize the need for more research, risk assessment and adoption of measures to minimize human exposure to these particles. Thus, MP pollution and its effects should be further investigated and addressed according to the WHO 'One Health' approach.

Occurrence of microplastics in commercial fish from a natural estuarine environment

Microplastic ingestion has been reported for several marine species, but the level of contamination in transitional systems and associated biota is less known. The aim of this study was to assess the occurrence of microplastic ingestion in three commercial fish species: the sea bass (Dicentrarchus labrax), the seabream (Diplodus vulgaris) and the flounder (Platichthys flesus) from the Mondego estuary (Portugal). Microplastics were extracted from the gastrointestinal tract of 120 individuals by visual inspection and digestion solution. A total of 157 particles were extracted from 38% of total fish (96% fibers), with 1.67 ± 0.27 (SD) microplastics per fish. Significantly higher amount of ingested microplastics was recorded for D. vulgaris (73%). The dominant polymers identified by μ-FTIR were polyester, polypropylene and rayon (semi-synthetic fiber). It is reported for the first time the presence of this pollutant in fish populations from the Mondego estuary raising concerns on their potential negative effects.

A little key to oxalate formation in oil paints: protective patina or chemical reactor?

A novel degradation mechanism for 19^th c. chrome yellow oil paints is proposed based on the oil photodegradation induced and calcium oxalate formation. It was proved by synchrotron radiation using artificially aged pigment reconstructions.

Plastic ingestion in oceanic-stage loggerhead sea turtles (Caretta caretta) off the North Atlantic subtropical gyre

Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1-5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic.

Genome sequencing of three bacteria associated to black band disease from a Colombian reef-building coral

We announce the draft genome sequence of three Gram-negative bacteria isolated from coral tissues affected with the black band disease (BBD), identified with the NCBI's Assembly Database accession numbers: MBQF, MAYB and MBQE. These genome drafts constitute an useful tool for the characterisation of these bacteria and for the understanding of the relationship between the microbial consortia associated with the disease and the onset and progression of the pathology.

Microplastics in coastal sediments from Southern Portuguese shelf waters

Microplastics are well-documented pollutants in the marine environment that result from fragmentation of larger plastic items. Due to their long chemical chains, they can remain in the environment for long periods of time. It is estimated that the vast majority (80%) of marine litter derives from land sources and that 70% will sink and remain at the bottom of the ocean. Microplastics that result from fragmentation of larger pieces of plastic are common to be found in beaches and in the water surface. The most common microplastics are pellets, fragments and fibres. This work provides original data of the presence of microplastics in coastal sediments from Southern Portuguese shelf waters, reporting on microplastic concentration and polymer types. Microplastic particles were found in nearly 56% of sediment samples, accounting a total of 31 particles in 27 samples. The vast majority were microfibers (25), identified as rayon fibres, and fragments (6) identified as polypropylene, through infrared spectroscopy (μ-FTIR). The concentration and polymer type data is consistent with other relevant studies and reports worldwide.

Evidence of microplastics in samples of zooplankton from Portuguese coastal waters

Records of high concentrations of plastic and microplastic marine debris floating in the ocean have led to investigate the presence of microplastics in samples of zooplankton from Portuguese coastal waters. Zooplankton samples collected at four offshore sites, in surveys conducted between 2002 and 2008, with three different sampling methods, were used in this preliminary study. A total of 152 samples were processed and microplastics were identified in 93 of them, corresponding to 61% of the total. Costa Vicentina, followed by Lisboa, were the regions with higher microplastic concentrations (0.036 and 0.033 no. m⁻³) and abundances (0.07 and 0.06 cm³ m⁻³), respectively. Microplastic: zooplankton ratios were also higher in these two regions, which is probably related to the proximity of densely populated areas and inputs from the Tejo and Sado river estuaries. Microplastics polymers were identified using Micro Fourier Transformed Infrared Spectroscopy (μ-FTIR), as polyethylene (PE), polypropylene (PP) and polyacrylates (PA). The present work is the first report on the composition of microplastic particles collected with plankton nets in Portuguese coastal waters. Plankton surveys from regular monitoring campaigns conducted worldwide may be used to monitor plastic particles in the oceans and constitute an important and low cost tool to address marine litter within the scope of the Marine Strategy Framework Directive (2008/56/EC).

A spectroscopic study of Brazilwood paints in medieval books of hours

In this work, microspectrofluorimetry was for the first time applied to the identification of the red organic lakes that are characteristic of the lavish illuminations found in 15(th) century books of hours. Microspectrofluorimetry identified those red paints, ranging from opaque pink to dark red glazes, as brazilwood lakes. An unequivocal characterization was achieved by comparison with reference paints produced following recipes from the medieval treatise The Book on How to Make Colours, and was further confirmed by fiber optic reflectance spectroscopy (FORS). For these treasured cultural objects, microspectrofluorimetry and FORS proved to be the only techniques that could identify, in situ or in microsamples, the chromophore responsible for the pinkish hues: a brazilein-Al(3+) complex. Additionally, a multi-analytical approach provided a full characterization of the color paints, including pigments, additives, and binders. Microspectroscopic techniques, based on infrared and X-ray radiation, enabled us to disclose the full palette of these medieval manuscripts, including the elusive greens, for which, besides malachite, basic copper sulfates were found; Raman microscopy suggested a mixture of brochantite and langite. Infrared analysis proved invaluable for a full characterization of the additives that were applied as fillers or whites (chalk, gypsum, and white lead) as well as the proteinaceous and polysaccharide binders that were found pure or in mixture.

Characterisation of varnishes used in violins by pyrolysis-gas chromatography/mass spectrometry

The correct characterisation and a detailed knowledge of the materials originally used in violin varnishes, like natural resins, is crucial for the conservation in museums and for a suitable restoration technique. The study presented here reports on the potential of pyrolysis (Py) coupled with gas chromatography (GC) and mass spectrometry (MS) for the identification of chemical markers of each resin; this technique is very sensitive and selective, it needs a small quantity of sample and does not require chemical treatments. To improve the chromatographic behaviour of polar compounds the derivatising agent tetramethylammonium hydroxide (TMAH) in combination with pyrolysis has been used, in the so-called TMAH thermochemolysis or thermally assisted hydrolysis and methylation (THM), or more simply pyrolysis-methylation. The natural resins studied were colophony, sandarac, manila copal, elemi, amber and benzoin, mainly composed of terpenic compounds, with the exception of the latter, composed of aromatic compounds. Many compounds were identified; in particular, methyl esters of resinous acids that, individually or in a group, can be used as chemical markers. However, through this technique it was not possible to distinguish between the sandarac and manila copal resins because their chromatographic behaviour is very similar. Finally, the procedure applied has been employed in the characterisation of original varnish samples.

Authentic cell-specific and developmentally regulated expression of pro-opiomelanocortin genomic fragments in hypothalamic and hindbrain neurons of transgenic mice

The pro-opiomelanocortin (POMC) gene is expressed in a subset of hypothalamic and hindbrain neurons and in pituitary melanotrophs and corticotrophs. POMC neurons release the potent opioid beta-endorphin and several active melanocortins that control homeostasis and feeding behavior. POMC gene expression in the CNS is believed to be controlled by distinct cis-acting regulatory sequences. To analyze the transcriptional regulation of POMC in neuronal and endocrine cells, we produced transgenic mice carrying POMC27*, a transgene containing the entire 6 kb of the POMC transcriptional unit together with 13 kb of 5' flanking regions and 8 kb of 3' flanking regions. POMC27* was tagged with a heterologous 30 bp oligonucleotide in the third exon. In situ hybridization studies showed an accurate cell-specific pattern of expression of POMC27* in the arcuate nucleus and the pituitary. Hypothalamic mRNA-positive neurons colocalized entirely with beta-endorphin immunoreactivity. No ectopic transgenic expression was detected in the brain. Deletional analyses demonstrated that neuron-specific expression of POMC transgenes required distal 5' sequences localized upstream of the pituitary-responsive proximal cis-acting elements that were identified previously. POMC27* exhibited a spatial and temporal pattern of expression throughout development that exactly paralleled endogenous POMC. RNase protection assays revealed that POMC27* expression mimicked that of POMC in different areas of the CNS and most peripheral organs with no detectable ectopic expression. Hormonal regulation of POMC27* and POMC was identical in the hypothalamus and pituitary. These results show that distal 5' sequences of the POMC gene located between -13 and -2 kb target expression into the CNS of transgenic mice in a precise neuron-specific, developmentally and hormonally regulated manner.

Accurate spatial and temporal transgene expression driven by a 3.8-kilobase promoter of the bovine beta-casein gene in the lactating mouse mammary gland

The spatial, temporal, and hormonal pattern of expression of the beta-casein gene is highly regulated and confined to the epithelial cells of the lactating mammary gland. Previous studies have shown that 1.7 kb of the bovine beta-casein promoter were able to drive cell-specific and hormone-dependent expression to a mouse mammary cell line but failed to induce accurate expression to the mammary gland of transgenic mice. We investigated here the ability of 3.8 kb of the bovine beta-casein gene promoter to drive the expression of the human growth hormone (hGH) gene in transgenic mice. A Northern blot analysis using total RNA obtained from different tissues of lactating and nonlactating females revealed the presence of hGH mRNA only in the mammary gland of lactating females. hGH mRNA was not detectable in the mammary gland of virgin females or males. A developmental analysis showed that hGH mRNA only peaked on parturition, resembling more closely the bovine beta-casein temporal expression pattern rather than the murine. In situ hibridization studies performed on mammary gland sections showed that the cellular pattern of hGH expression was homogeneous in all lobules from heterozygous and homozygous transgenic mice. Silver grain counts on the tissue sections highly correlated with the hGH contents in the milk determined by radioimmunoassay (r = 0.996). Thus 3.8 kb of the bovine beta-casein promoter direct a high-level expression of a reporter gene to the lactating mammary gland of transgenic mice in a tissue-specific and developmentally regulated manner.