N-Methyl-D-aspartic Acid (NMDA) in the nervous system of the amphioxus Branchiostoma lanceolatum

<p>Abstract</p> <p>Background</p> <p>NMDA (<it>N</it>-methyl-D-aspartic acid) is a widely known agonist for a class of glutamate receptors, the NMDA type. Synthetic NMDA elicits very strong activity for the induction of hypothalamic factors and hypophyseal hormones in mammals. Moreover, endogenous NMDA has been found in rat, where it has a role in the induction of GnRH (Gonadotropin Releasing Hormone) in the hypothalamus, and of LH (Luteinizing Hormone) and PRL (Prolactin) in the pituitary gland.</p> <p>Results</p> <p>In this study we show evidence for the occurrence of endogenous NMDA in the amphioxus <it>Branchiostoma lanceolatum</it>. A relatively high concentration of NMDA occurs in the nervous system of this species (3.08 ± 0.37 nmol/g tissue in the nerve cord and 10.52 ± 1.41 nmol/g tissue in the cephalic vesicle). As in rat, in amphioxus NMDA is also biosynthesized from D-aspartic acid (D-Asp) by a NMDA synthase (also called D-aspartate methyl transferase).</p> <p>Conclusion</p> <p>Given the simplicity of the amphioxus nervous and endocrine systems compared to mammalian, the discovery of NMDA in this protochordate is important to gain insights into the role of endogenous NMDA in the nervous and endocrine systems of metazoans and particularly in the chordate lineage.</p

Assessing safety functionalities in the design and validation of driving automation

This paper aims to contribute to the comprehensive and systematic safety assessment of Automated Driving Systems (ADSs) by identifying unknown hazardous areas of operation. The current methodologies employed in this domain typically involve estimating the distributions of situational variables based on human-centered field test, crash databases, or expert knowledge of critical values. However, due to the lack of a-priori knowledge regarding the influential factors, their critical ranges, and their distributions, these approaches may not be entirely suitable for the assessment of emerging automated driving technologies. To deal with this challenging problem, here we propose a testing methodology incorporating realistic yet unobserved driving conditions, distinguished by numerous situational variables, so to encompass unknown unsafe conditions comprehensively. Our methodology utilizes stochastic simulation and uncertainty modeling techniques to account for the variability of realistic driving conditions and their impact on ADSs' performances. By doing so, we aim to identify unsafe operational regions and triggering conditions that can lead to hazardous behaviors, thus improving the development and safety of automated driving functions. For our purposes, the Latin Hypercube Sampling technique and the recently proposed PAWN density-based sensitivity analysis method are employed. We apply this methodology for the first time in the specific field of ADSs design and validation, using an exemplificative use case. We discuss and compare the results obtained from our approach with those obtained from a traditional approach

Individual differences and knockout in zebrafish reveal similar cognitive effects of BDNF between teleosts and mammals

The remarkable similarities in cognitive performance between teleosts and mammals suggest that the underlying cognitive mechanisms might also be similar in these two groups. We tested this hypothesis by assessing the effects of the brain-derived neurotrophic factor (BDNF), which is critical for mammalian cognitive functioning, on fish's cognitive abilities. We found that individual differences in zebrafish's learning abilities were positively correlated with bdnf expression. Moreover, a CRISPR/Cas9 mutant zebrafish line that lacks the BDNF gene (bdnf(-/-)) showed remarkable learning deficits. Half of the mutants failed a colour discrimination task, whereas the remaining mutants learned the task slowly, taking three times longer than control bdnf(+/+) zebrafish. The mutants also took twice as long to acquire a T-maze task compared to control zebrafish and showed difficulties exerting inhibitory control. An analysis of habituation learning revealed that cognitive impairment in mutants emerges early during development, but could be rescued with a synthetic BDNF agonist. Overall, our study indicates that BDNF has a similar activational effect on cognitive performance in zebrafish and in mammals, supporting the idea that its function is conserved in vertebrates

Induction of Cytotoxic Oxidative Stress by d-Alanine in Brain Tumor Cells Expressing Rhodotorula gracilis d-Amino Acid Oxidase: A Cancer Gene Therapy Strategy

Overview summary Gene-directed enzyme prodrug therapy (GDEPT) is an antineoplastic treatment strategy designed to overcome the systemic toxicity of chemotherapy by specifically expressing a foreign enzyme in malignant cells that converts a nontoxic prodrug into a cytotoxic metabolite. The relative inefficiency of current in situ gene transfer methodology suggests that enzyme/prodrug combinations that produce membrane permeable metabolites will elicit a more favorable therapeutic response. Ideally, the agent produced by the transduced cell “factories” would be cytotoxic toward both proliferating and quiescent cells. We describe a novel GDEPT approach using d-amino acid oxidase from the red yeast Rhodotorula gracilis and d-alanine as a substrate that generates hydrogen peroxide, a reactive metabolite of oxygen that has both these characteristics. We also demonstrate the ability to sensitize tumor cells to this GDEPT protocol by manipulating cellular antioxidant pathways.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63220/1/hum.1998.9.2-185.pd

Zebrafish, a novel model system to study uremic toxins: The case for the sulfur amino acid lanthionine

The non-proteinogenic amino acid lanthionine is a byproduct of hydrogen sulfide biosynthesis: the third endogenous vasodilator gas, after nitric oxide and carbon monoxide. While hydrogen sulfide is decreased in uremic patients on hemodialysis, lanthionine is increased and has been proposed as a new uremic toxin, since it is able to impair hydrogen sulfide production in hepatoma cells. To characterize lanthionine as a uremic toxin, we explored its effects during the early development of the zebrafish (Danio rerio), a widely used model to study the organ and tissue alterations induced by xenobiotics. Lanthionine was employed at concentrations reproducing those previously detected in uremia. Light-induced visual motor response was also studied by means of the DanioVision system. Treatment of zebrafish embryos with lanthionine determined acute phenotypical alterations, on heart organogenesis (disproportion in cardiac chambers), increased heart beating, and arrhythmia. Lanthionine also induced locomotor alterations in zebrafish embryos. Some of these effects could be counteracted by glutathione. Lanthionine exerted acute effects on transsulfuration enzymes and the expression of genes involved in inflammation and metabolic regulation, and modified microRNA expression in a way comparable with some alterations detected in uremia. Lanthionine meets the criteria for classification as a uremic toxin. Zebrafish can be successfully used to explore uremic toxin effects

Polymer co-crystalline films for photonics

Robust syndiotactic polystyrene (sPS) films exhibiting highly stable co-crystalline phases can be obtained with a large variety of low-molecular-mass chromophore guest molecules. In this report different aspects relative to the structure and the optical properties of these films are described. In particular, possible applications of these films as fluorescent materials, as optical memories (based on the co-crystallization of photoreactive guest molecules), as non-linear optical materials (with polar guests) and as chiro-optical memories (based on temporary co-crystals with chiral guest molecules) are presented

Brain Proteome and Behavioural Analysis in Wild Type, BDNF+/− and BDNF−/− Adult Zebrafish (Danio rerio) Exposed to Two Different Temperatures

Experimental evidence suggests that environmental stress conditions can alter the expression of BDNF and that the expression of this neurotrophin influences behavioural responses in mammalian models. It has been recently demonstrated that exposure to 34 degrees C for 21 days alters the brain proteome and behaviour in zebrafish. The aim of this work was to investigate the role of BDNF in the nervous system of adult zebrafish under control and heat treatment conditions. For this purpose, zebrafish from three different genotypes (wild type, heterozygous BDNF+/- and knock out BDNF-/-) were kept for 21 days at 26 degrees C or 34 degrees C and then euthanized for brain molecular analyses or subjected to behavioural tests (Y-maze test, novel tank test, light and dark test, social preference test, mirror biting test) for assessing behavioural aspects such as boldness, anxiety, social preference, aggressive behaviour, interest for the novel environment and exploration. qRT-PCR analysis showed the reduction of gene expression of BDNF and its receptors after heat treatment in wild type zebrafish. Moreover, proteomic analysis and behavioural tests showed genotype- and temperature-dependent effects on brain proteome and behavioural responding. Overall, the absent expression of BDNF in KO alters (1) the brain proteome by reducing the expression of proteins involved in synapse functioning and neurotransmitter-mediated transduction; (2) the behaviour, which can be interpreted as bolder and less anxious and (3) the cellular and behavioural response to thermal treatment

Opposing effects of D-aspartic acid and nitric oxide on tuning of testosterone production in mallard testis during the reproductive cycle

<p>Abstract</p> <p>Background</p> <p>D-Aspartic acid (D-Asp) and nitric oxide (NO) play an important role in tuning testosterone production in the gonads of male vertebrates. In particular, D-Asp promotes either the synthesis or the release of testosterone, whereas NO inhibits it. In this study, we have investigated for the first time in birds the putative effects of D-Asp and NO on testicular testosterone production in relation to two phases of the reproductive cycle of the adult captive wild-strain mallard (Anas platyrhynchos) drake. It is a typical seasonal breeder and its cycle consists of a short reproductive period (RP) in the spring (April-May) and a non reproductive period (NRP) in the summer (July), a time when the gonads are quiescent. The presence and the localization of D-Asp and NO in the testis and the trends of D-Asp, NO and testosterone levels were assessed during the main phases of the bird's reproductive cycle. Furthermore, in vitro experiments revealed the direct effect of exogenously administered D-Asp and NO on testosterone steroidogenesis.</p> <p>Methods</p> <p>By using immunohistochemical (IHC) techniques, we studied the presence and the distributional pattern of D-Asp and NO in the testes of RP and NRP drakes. D-Asp levels were evaluated by an enzymatic method, whereas NO content, via nitrite, was assessed using biochemical measurements. Finally, immunoenzymatic techniques determined testicular testosterone levels.</p> <p>Results</p> <p>IHC analyses revealed the presence of D-Asp and NO in Leydig cells. The distributional pattern of both molecules was in some way correlated to the steroidogenic pathway, which is involved in autocrine testosterone production. Indeed, whereas NO was present only during the NRP, D-Asp was almost exclusively present during the RP. Consistently, the high testosterone testicular content occurring during RP was coupled to a high D-Asp level and a low NO content in the gonad. By contrast, in sexually inactive drakes (NRP), the low testosterone content in the gonad was coupled to a low D-Asp content and to a relatively high NO level. Consequently, to determine the exogenous effects of the two amino acids on testosterone synthesis, we carried out in vitro experiments using testis sections deriving from both the RP and NRP. When testis slices were incubated for 60 or 120 min with D-Asp, testosterone was enhanced, whereas in the presence of L-Arg, a precursor of NO, it was inhibited.</p> <p>Conclusion</p> <p>Our results provide new insights into the involvement of D-Asp and NO in testicular testosterone production in the adult captive wild-strain mallard drake. The localization of these two molecules in the Leydig cells in different periods of the reproductive cycle demonstrates that they play a potential role in regulating local testosterone production.</p

Serum Oxytocin, Cortisol and Social Behavior in Calves: A Study in the Impossible Task Paradigm

In this study, we explored the correlations between circulating levels of oxytocin, cortisol, and different social behaviors toward humans in 26 Italian Red Pied calves (all females, with an average age of 174 ± 24 days) using the impossible task paradigm. This paradigm has proved fruitful in highlighting the effect of socialization on the willingness to interact with humans in several domesticated species. The test consists of the violation of an expectation (recovering food from an experimental apparatus) while a caregiver and a stranger are present. Immediately after the end of the test (less than one minute), blood was collected from the coccygeal vein. Statistics were performed by the Spearman’s rank correlation; significant differences were adjusted according to Bonferroni’s correction. Cortisol correlates positively (ρ = 0.565; p < 0.05) with the latency of behaviors directed at the caregiver, and the duration of behaviors directed at the apparatus correlates negatively with both the caregiver (ρ = −0.654; p < 0.05) and a stranger (ρ = −0.644; p < 0.05). Contrary to what is reported in the literature on cows, no correlations were found between oxytocin levels and direct behaviors toward the caregiver. This highlights a different behavioral strategy between calves and cows when placed in front of an impossible task

Penile cancer: prognostic and predictive factors in clinical decision-making

: Penile cancer (PC) is a typical tumor of non-industrialized countries. The incidence is 20-30 times higher in Africa and South America, considering the elevated prevalence of sexually transmitted diseases. Histologically, PC includes squamous cell carcinoma (SCPC), the most frequent, and nonsquamous carcinoma (NSCPC). Early diagnosis is the goal, whereas later diagnosis relates to poor functional outcomes and worse prognosis. The 5-year survival rate is 85% for patients with histologically regional negative lymph nodes, compared to 29%-40% for those with histologically regional positive lymph nodes. To date no new drugs are approved, and there are few new data about molecular mechanisms underlying tumorigenesis. The SCPC remains a rare tumor and the current therapeutic algorithm is based principally on retrospective analysis and less on prospective trials. In this review article, biomarkers of prognosis and efficacy of current treatments are summarized with a focus on those that have the potential to affect treatment decision-making in SCPC