An hypothesis on crustacean pigmentation metabolism:L-carnitine and nuclear hormone receptors as limiting factors

Astaxanthin (Axn) is the primary pigment molecule in crustaceans associated with quality, health and growth traits, leading to increased marketing value. Axn can be contained within the protein complex crustacyanin (CRCN) to produce an array of different shell colours, or esterified with fatty acids (FA) for storage but also contributing additional red colouration. l-Carnitine (LC) has a major role in FA oxidation and mitochondrial function optimization, which could influence the proportion of Axn complexed with FA or CRCN. Peroxisome proliferator activated receptors (PPARs) have important roles in FA and Axn uptake, and stored lipid oxidation affecting Axn homeostasis and storage in lipid bodies. Whether Axn could increase PPAR signalling and carnitine palmitoyl transferase activity, leading to induction of lipid metabolism, is not known in crustaceans. Several FA have been shown to preferentially form FA Axn-esters, including saturated fatty acids (SFA) such as C16:0 and C18:0, mono-unsaturated fatty acids (MUFA) such as C16:1 and C18:1, and poly-unsaturated fatty acids (PUFA) such as C20:4, C20:5, and C20:6. We hypothesize that manipulating the dietary ratios and inclusion of LC, Axn, and specific FA may be able to further improve pigment utilization, lipid metabolism, health, and growth in crustaceans.</p

Dynamics of energy reserves and the cost of reproduction in female and male fiddler crabs

The physiological costs of reproduction can be measured as the energy allocated to reproductive activities. In fiddler crabs, females allocate energy to vitellogenesis and brooding, whereas males perform expensive courtship behaviors. We evaluated in a large-scale study the reproduction cost of females and males of Leptuca uruguayensis in a temperate estuary, where their reproductive efforts are synchronized in a short reproductive season. The reproductive investments (vitellogenesis, spermatophore production, and male reproductive behaviors) were measured and related to the dynamics of storage and expenditure of energy reserves (glycogen, total lipids, and total protein) in the hepatopancreas, ovary, and muscle of the enlarged cheliped, throughout one annual cycle. Maximum energy storage occurred in winter, a period of low activity, whereas minimum energy storage occurred during the reproductive period, characterized by expensive activities. The glycogen reserves of the hepatopancreas decreased about 66% in females and 61% in males, suggesting high and similar physiological costs of reproduction between sexes, despite their different reproductive strategies to maximize their fitness.Instituto de Limnología "Dr. Raúl A. Ringuelet

Density and gender segregation effects in the culture of the caridean ornamental red cherry shrimp <i>Neocaridina davidi</i> Bouvier, 1904 (Caridea: Atyidae)

The effect of density on growth, sex ratio, survival, and biochemical composition of the red cherry shrimp, Neocaridina davidi Bouvier, 1904, was studied to determine optimum rearing conditions in this ornamental species. It was tested whether gender segregation affected growth and survival of the species. To test the effect of density (Experiment 1), hatched juvenile shrimp were kept at three different densities: 2.5, 5, and 10 individuals l-1 (D2.5, D5 and D10, respectively). To test the effect of gender segregation (Experiment 2), 30-day juveniles were reared in three conditions: culture with only females, culture with only males, and mixed culture (females: males 1:1) at 5 individuals l-1 density. Experiments lasted 90 days, and shrimp were weighted either every 30 days (Experiment 1) or 15 days (Experiment 2). At day 90, females kept at D2.5 weighted 45% more than females stocked at D10 (P 5 0.05). Males at D2.5 weighted 29% more than D510 (P 2.5 had the lowest lipid and protein content, which would occur if they had a higher spawning. Males from D2.5 had higher content of proteins, probably due to their larger size. Gender segregation had no effect over growth and survival; females grew up to a larger size than males both in monosex and mixed culture. It was shown that given to their non-aggressive behavior, N. davidi is tolerant to a highdensity condition, which makes it feasible as an ornamental species.Instituto de Limnología "Dr. Raul A. Ringuelet

Morfología de los otolitos sagitta, lapillus y asteriscus de Genidens barbus de distribución patagónica

Otoliths are calcium carbonate structures, deposited as aragonite, located in the inner ear of bony fish. In recent years, they have become a useful tool for the determination of fish species, trophic content, age studies, and the identification of fish stocks. The objective of this work was to describe the morphology of the three pairs of otoliths of the marine catfish Genidens barbus of Patagonian distribution. Otoliths of specimens obtained at four sampling points in the Negro River were analyzed. It was observed that otoliths presented the general morphological pattern proposed for Siluriformes, where lapilli are the largest and most robust of the three. Lapillus presented a rounded shape, a pronounced elevation in the central position, a delimited sulcus, but not very evident, without evidence of a minor sulcus. The sagitta is claviform, with an elongated conical posterior region, dorsal wings that continue as lateral expansions called basal wings, and the presence of a fissure. The asteriscus has an ear shape, a median opening, a short pointed rostrum, a poorly developed anti-rostrum and a slightly curved acoustic fossa. In this work, sagitta and asteriscus otoliths were described for the first time for the species G. barbus, thus completing the description of the three pairs.Los otolitos son estructuras de carbonato de calcio, depositado en forma de aragonita, ubicados en el oído interno de peces óseos. En los últimos años se han convertido en una herramienta útil para la determinación de especies ícticas, estudios de edad, contenidos tróficos, identificación de stocks pesqueros. El objetivo del presente trabajo fue describir la morfología de los tres pares de otolitos del bagre marino Genidens barbus de distribución patagónica. Se analizaron los otolitos de ejemplares obtenidos en cuatro puntos de muestreo en el Río Negro. Se observó que los otolitos presentan el patrón morfológico general propuesto para Siluriformes, donde los lapilli son los más grandes y robustos de los tres. El lapillus presentó forma redondeada, elevación pronunciada en posición central, sulcus delimitado, pero poco evidente, sin evidencia de sulcus menor. La sagitta es claviforme, con región posterior cónica alargada, alas dorsales que se continúan como expansiones laterales denominadas alas basales y presencia de fisura. El asteriscus tiene forma auricular, abertura mediana, rostro corto aguzado, antirrostro poco desarrollado y fosa acústica poco curva. En este trabajo se describen por primera vez los otolitos sagitta y asteriscus para la especie G. barbus, completando así la descripción de los tres pares

Investigaciones recientes sobre el langostino nativo Macrobrachium americanum (Decapoda: Palaemonidae) con fines de acuicultura y conservación

where good management practices on aquaculture are mandatory. The economic and ecological importance of prawns of the Genus Macrobrachium cause an impact at a global level involving economic, academic and social aspects. Macrobrachium americanum appears as one of the genus species with high nutritional value and an economic demand in the national and international markets, as well as a vital income for fisherman and producers of this species. For researchers, it is a challenge to find solutions to culture and propose conservation measures for M. americanum with emphasis on development, nutrition and reproduction. Although there are scientific studies supporting the economic importance of this species, our knowledge about its cultivation, reproduction and conservation is limited. This paper summarizes the latest studies made in cooperation with M. americanum in research lead by the Centro de Investigaciones Biológicas del Noroeste, Mexico. After several years of continuous research, it is considered that those efforts have produced useful information for the sustainable exploitation, conservation and basic management practices of this species.En los últimos tiempos ha existido una gran preocupación por la conservación y uso adecuados de los recursos naturales vivos, donde las buenas prácticas de manejo en la acuicultura son importantes. La importancia económica y pesquera de los langostinos del Género Macrobrachium causa un impacto a nivel global que incluye aspectos económicos, académicos y sociales. Macrobrachium americanum se presenta como una de las especies del género con alto valor nutritivo y demanda económica en el mercado nacional e internacional y constituye un importante ingreso para los pescadores y productores de esta especie. Para los investigadores es un desafío encontrar soluciones para la conservación del M. americanum con énfasis en el desarrollo, la nutrición y la reproducción. Aunque existen estudios científicos que avalan la importancia económica de esta especie, nuestro conocimiento sobre su cultivo, reproducción y conservación es limitado. Este artículo resume algunos estudios en colaboración sobre M. americanum, liderados por el Centro de Investigaciones Biológicas del Noroeste, México. Después de varios años de investigación continua, se considera que esos esfuerzos han producido información útil para la explotación sostenible, conservación y las posibles medidas de manejo para esta especie

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M&gt;70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0&lt;e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

La renovación de la palabra en el bicentenario de la Argentina : los colores de la mirada lingüística

El libro reúne trabajos en los que se exponen resultados de investigaciones presentadas por investigadores de Argentina, Chile, Brasil, España, Italia y Alemania en el XII Congreso de la Sociedad Argentina de Lingüística (SAL), Bicentenario: la renovación de la palabra, realizado en Mendoza, Argentina, entre el 6 y el 9 de abril de 2010. Las temáticas abordadas en los 167 capítulos muestran las grandes líneas de investigación que se desarrollan fundamentalmente en nuestro país, pero también en los otros países mencionados arriba, y señalan además las áreas que recién se inician, con poca tradición en nuestro país y que deberían fomentarse. Los trabajos aquí publicados se enmarcan dentro de las siguientes disciplinas y/o campos de investigación: Fonología, Sintaxis, Semántica y Pragmática, Lingüística Cognitiva, Análisis del Discurso, Psicolingüística, Adquisición de la Lengua, Sociolingüística y Dialectología, Didáctica de la lengua, Lingüística Aplicada, Lingüística Computacional, Historia de la Lengua y la Lingüística, Lenguas Aborígenes, Filosofía del Lenguaje, Lexicología y Terminología

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Compensatory Growth in Juveniles of Freshwater Redclaw Crayfish Cherax quadricarinatus Reared at Three Different Temperatures: Hyperphagia and Food Efficiency as Primary Mechanisms.

Feeding restriction, as a trigger for compensatory growth, might be considered an alternative viable strategy for minimizing waste as well as production costs. The study assessed whether juvenile redclaw crayfish Cherax quadricarinatus (initial weight 0.99 ± 0.03 g) was able to compensate for feeding restriction at different temperatures (23 ± 1, 27 ± 1 and 31 ± 1 ° C). Hyperphagia, food utilization efficiency, energetic reserves, and hepatopancreas structure were analyzed. Three temperatures and two feeding regimes (DF-daily fed throughout the experiment and CF- 4 days food deprivation followed by 4 days of feeding, intermittently) were tested. The restriction period was from day 1 to 45, and the recovery period was from day 45 to 90. The previously restricted crayfish held at 23, 27, and 31 ± 1 ° C displayed complete body weight catch-up through compensatory growth following the restriction period with depressed growth. The mechanisms that might explain this response were higher feed intake (hyperphagia), and increased food utilization efficiency. Hepatopancreatic lipids were used as a metabolic fuel and hepatosomatic index was reduced in the previously restricted crayfish, but recovery at the same level of unrestricted crayfish occurred after the shift to daily feeding. The highest temperature affected adversely growth, feed intake, food efficiency, and metabolism of crayfish, whereas the lowest temperature and feeding restriction induced a more efficient growth of the crayfish

Intersex females in the red claw crayfish, Cherax quadricarinatus (Decapoda: Parastacidae)

Cherax quadricarinatus is a large freshwater crayfish species (Parastacidae) native of north-west Queensland and the Northern Territory of Australia. The species typically exhibits a gonochoristic sexual system, although in cultured populations various types of intersex individuals have been described as functional males. In the present study, the macroscopic morphology and the gonadal histology of one type of intersex are described and discussed. All intersexes having both pairs of genital openings (female and male openings) and lacking both appendix masculinae and red patches were functional females with normal ovaries and oviducts. From a histological point of view, they did not differ from normal females having previtellogenic and/or vitellogenic ovaries according to size