Time for change in Portuguese science

There is an almost perfect positive relationship between scientific output and gross domestic product (GDP) in Western Europe (Fig. 1). But two countries — Ireland and Portugal — spoil the relationship

Are Atoms the Bricks of Molecules?

The celebrations of the International Year of the Periodic Table (IYPT2019) brought to public attention that the 118 atoms, included and systematized in the periodic table, are the building blocks of everything that exists in the universe. We can even go further in that line of thought, by including time, saying that everything that existed in the past, present or the future in the universe is made of atoms: The periodic table is a Window to Eternity. Quantum Mechanics changed the paradigm of looking at atomic and molecular structures by creating the concept of probabilistic charge distributions commonly known as the electronic cloud. But this electronic cloud cannot be reproduced from the superposition of atomic charge distributions except at nuclei and core electron levels. The valence electrons have their distributions strongly affected by constructive and destructive interference to a point where there will be no resemblance to their atomic counterparts. Can we recover the concept of atom from that distorted mess? How do we split the charge density of a bond between the two intervening atoms? What are lone pairs? Do they belong to an atom? What’s a ring (like in benzene)? We will try to bridge the gap between the quantum formulation and the traditional chemical view.info:eu-repo/semantics/publishedVersio

Water calcium concentration modifies whole-body calcium uptake in sea bream larvae during short-term adaptation to altered salinities

Whole-body calcium uptake was studied in gilthead sea bream larvae (9–83·mg) in response to changing environmental salinity and [Ca2+]. Calcium uptake increased with increased fish size and salinity. Fish exposed to calcium-enriched, diluted seawater showed increased calcium uptake compared with fish in diluted seawater alone. Calcium uptake was unchanged in Na+- enriched, diluted seawater. Overall, [Ca2+], and not salinity/osmolarity per se, appears to be the main factor contributing to calcium uptake. By contrast, drinking was reduced by a decrease in salinity/osmolarity but was little affected by external [Ca2+]. Calculations of the maximum contribution from drinking-associated calcium uptake showed that it became almost insignificant (less than 10%) through a strong decrease in drinking rate at low salinities (0–8‰). Diluted seawater enriched in calcium to the concentration present in full-strength seawater (i.e. constant calcium, decreasing salinity) restored intestinal calcium uptake to normal. Extra-intestinal calcium uptake also benefited from calcium addition but to a lesser extent

Hormonal control of swimbladder sonic muscle dimorphism in the Lusitanian toadfish, Halobatrachus didactylus

The swimbladder and associated sonic muscle of the Lusitanian toadfish Halobatrachus didactylus increase in size throughout life and are, respectively, 25% and 30% larger in type I (nest-holder) males than females, which may generate sexual differences in sound production. Sexual dimorphism in swimbladder is also evident in the morphological features of sonic muscle fibers. During the breeding season, type I males have smaller myofibril contracting zones surrounded by larger sarcoplasm areas compared with females, possibly an adaptation to speed and fatigue resistance for the production of long mating calls. Type II (floater) males show characteristics that are intermediate, but statistically not significantly different, between type I males and females. Six weeks after castration and androgen (testosterone and 11- ketotestosterone) replacement in type I and type II males there were no alterations either in swimbladder mass or fiber morphology. However, 17b-estradiol induced a significant decrease in swimbladder mass and sarcoplasm area/myofibril area ratio. Six months after castration there was a clear reduction in the seasonal swimbladder hypertrophy in males and induction of sonic fiber morphological characteristics that resemble those occurring in females (low sarcoplasm area/myofibril area ratio). These results suggest that testicular factors are required to initiate sonic muscle hypertrophy and type I sonic fiber phenotype in H. didactylus, but a specific involvement of androgens has not been completely clarified

The swimbladder of the Lusitanian toadfish: sexual dimorphism and hormonal control

The members of the family Batrachoididae produce sounds associated with courtship and agonistic interactions. While long mating calls are only produced by nesting males, agonistic short duration grunts have been recorded from toadfishes and midshipmen in both males (nesting or not) and females. Sound production results from the contraction of paired sonic muscles attached to the walls of the swimbladder, which cause a rapid variation in swimbladder volume and internal pressure. Both sonic muscle growth and sonic fibre morphology have been shown to be androgen sensitive in batrachoidids

Morphometric changes and sex steroid levels during the annual reproductive cycle of the Lusitanian toadfish, Halobatrachus didactylus

The Lusitanian toadfish has group synchronous oocytes, which grow from November until June–July when they are released probably as a single batch. Blood plasma levels of estradiol-17b (E2) and testosterone (T) increase during vitellogenesis and drop rapidly during final maturation and ovulation, when 17,20b, 21-trihydroxy-4-pregnen-3-one (17,20b,21-P) levels increase. The male reproductive apparatus is composed of paired testes and multichambered accessory glands, which secrete mucosubstances and are connected to the spermatic duct. Changes in the gonadosomatic index of males paralleled the females but started to drop slightly earlier. The swimbladder and accessory glands also underwent important seasonal changes in weight reaching a maximum at spawning. T, 11-ketotestosterone (11-KT) and 17,20a-dihydroxy-4-pregnen-3-one (17,20a-P) were generally low except for a sharp peak in June. 17,20b,21-P also peaked in June and then declined slowly. 17,20b-dihydroxy-4-pregnen-3-one (17,20a-P) was undetectable in males and females. As with other species of the family two types of males were identified: type I males with smaller testes (ca. 7-fold) and larger accessory glands (ca. 3-fold) and swimbladders than type II. Type I males also had significantly higher (ca. 6- fold) 11-KT levels than type II males. This suggests a role for 11-KT in the development of structures important for reproductive behaviour

Nemo through the looking-glass: a commentary on Desjardins & Fernald

info:eu-repo/semantics/publishedVersio

Follow your nose: chemical communication throughout the European eel (Anguilla anguilla, L.) life-cycle

European eels are important in both scientific and economic terms. Unfortunately, current populations are becoming increasingly endangered and urgentmanagement is needed. Several aspects of eel biology, together with their highly developed sense of smell, suggest that chemical communication could be involved at key stages of their life-history. Thus, advances in this area could generate novel tools for stock management

Gill transcriptome response to changes in environmental calcium in the green spotted puffer fish

Abstract Background Calcium ion is tightly regulated in body fluids and for euryhaline fish, which are exposed to rapid changes in environmental [Ca2+], homeostasis is especially challenging. The gill is the main organ of active calcium uptake and therefore plays a crucial role in the maintenance of calcium ion homeostasis. To study the molecular basis of the short-term responses to changing calcium availability, the whole gill transcriptome obtained by Super Serial Analysis of Gene Expression (SuperSAGE) of the euryhaline teleost green spotted puffer fish, Tetraodon nigroviridis, exposed to water with altered [Ca2+] was analysed. Results Transfer of T. nigroviridis from 10 ppt water salinity containing 2.9 mM Ca2+ to high (10 mM Ca2+ ) and low (0.01 mM Ca2+) calcium water of similar salinity for 2-12 h resulted in 1,339 differentially expressed SuperSAGE tags (26-bp transcript identifiers) in gills. Of these 869 tags (65%) were mapped to T. nigroviridis cDNAs or genomic DNA and 497 (57%) were assigned to known proteins. Thirteen percent of the genes matched multiple tags indicating alternative RNA transcripts. The main enriched gene ontology groups belong to Ca2+ signaling/homeostasis but also muscle contraction, cytoskeleton, energy production/homeostasis and tissue remodeling. K-means clustering identified co-expressed transcripts with distinct patterns in response to water [Ca2+] and exposure time. Conclusions The generated transcript expression patterns provide a framework of novel water calcium-responsive genes in the gill during the initial response after transfer to different [Ca2+]. This molecular response entails initial perception of alterations, activation of signaling networks and effectors and suggests active remodeling of cytoskeletal proteins during the initial acclimation process. Genes related to energy production and energy homeostasis are also up-regulated, probably reflecting the increased energetic needs of the acclimation response. This study is the first genome-wide transcriptome analysis of fish gills and is an important resource for future research on the short-term mechanisms involved in the gill acclimation responses to environmental Ca2+ changes and osmoregulation.Peer Reviewe

Decoloración y detoxificación de aguas de alperujo mediante el empleo de esmectitas e hidrotalcita

2 páginas.-- 1 figura.-- 1 tablas.-- 8 referencias.-- Poster presentado en XXIV Reunión de la Sociedad Española de Arcillas Sevilla. Libro de Resúmenes: Noviembre de 2015 en Sevilla.El alperujo es el residuo sólido del proceso de extracción de aceite de oliva virgen en dos fases, que se produce en grandes cantidades en diversas regiones españolas y cuyo empleo como fertilizante y enmendante de suelos, una vez compostado, facilita una salida sostenible para estos contribuyendo favorablemente al secuestro de carbono (1,2) No obstante también puede dar lugar a algunos efectos adversos: a) Coloración de las aguas, b) Deterioro del suelo por su acidez y sales, c) Solubilización, transporte y lixiviación de algunos metales pesados y plaguicidas (3, 4) y d) Fitotoxicidad sobre plantas y microrganismos acuáticos, si no han sido previamente compostados o tratados (5). Sobre la hipótesis del conocido potencial de los materiales arcillosos de interaccionar con la materia orgánica soluble (MOS) de suelos, sedimentos o residuos (4, 6), el objetivo del presente trabajo ha sido evaluarla capacidad de arcillas catiónicas y aniónicas como adsorbentes de la MOS procedente de alperujo, responsable de los efectos adversos descritos. La finalidad última es el posible desarrollo y utilidad de adsorbentes naturales para reducir la coloración y toxicidad de aguas de lavado de almazaras, o para su posible co-aplicación con alperujo a suelos agrícolas disminuyendo los efectos adversos sobre semillas o plantas o para corregir los efectos de un vertido puntual incontrolado.Este trabajo ha sido financiado a través de los proyectos P07-AGR-03077 y P11-AGR-07400 y AGR-264 de la Junta de Andalucía, cofinanciados por FEDER y FSE; y el Convenio RECUPERA 2020 del MINECO-CSIC.Peer reviewe