Effect of Neuroactive Compounds on the Settlement of Mussel (Perna Canaliculus) Larvae

Herein, we present the first laboratory study on the effects of pharmacologically active compounds on larval settlement of the green-lipped mussel, Perna canaliculus. Competent hatchery-reared larvae were exposed to seawater containing excess K+ in the form of KCl and K2SO4 and the neurotransmitters -aminobutyric acid (GABA) and acetylcholine. Both KCl and K2SO4 were identified as active inducers of larval settlement with maximum inductions occurring after exposures to 10 and 7.5 mM, respectively. Peak settlement response to KCl was higher (>64%) than that achieved with K2SO4 (>41%). GABA did not induce larval settlement and displayed toxic and settlement inhibitive effects at 10-4 and 10-3 M. Acetylcholine induced larval settlement (>49%) at 10-4 M with minimal acute toxic effects (LC < 10%). To gain insight into the class of acetylcholine receptors involved, atropine was used to block the muscarinic-type receptors. Atropine treatment alone did not inhibit settlement compared to control assays, indicating that muscarinic-type receptors are not involved in settlement behavior. Furthermore, results showed that atropine did not significantly decrease acetylcholine induced settlement responses, which suggests an active role of the nicotinic-type receptors in the biochemical pathways of mussel settlement. Results of this study provide new insights on the mechanism of settlement behavior in P. canaliculus, which may have direct application to the growing New Zealand aquaculture industry

Neurophysiological Control of Swimming Behaviour, Attachment and Metamorphosis in Black-footed Abalone (Haliotis Iris) Larvae

Experiments were conducted to test the effect of a range of chemicals on larval responses in swimming behaviour, attachment and metamorphosis of the black-footed abalone (Haliotis iris). The effect of antibiotics on larval survival was first tested within negative (filtered seawater) and positive (GABA at 10−5, 10−4 and 10−3 mol L−1) control assays over 3 days. This experiment corroborated the effectiveness of using antibiotics to improve survival of larvae without obvious synergistic interactions with the GABA inducer or confounding effects of potential bacterial interactions. Chemical treatments (acetylcholine, potassium chloride, dopamine and glutamine) were then tested at various concentrations for their ability to modulate swimming behaviour and induce larval attachment and metamorphosis over 14 days. Generally, larval state shifted from swimming to attached, and from attached to metamorphosed, in the control and treatments over time. However, the peak percentage of attached and metamorphosed larvae varied in time among chemicals and concentrations. While overall percent metamorphosis was minimally enhanced after 14 days of exposure to some chemical treatments at certain concentrations, all treatments displayed significant capacities to down-regulate larval swimming and induce early attachment and metamorphosis. Mortality was recorded throughout the duration of the experiment, and was generally low (<20%) across controls and most treatments for exposures of less than 12 days. Interpretations of specific results from this study are used to elucidate neurophysiological control of larval activities for this abalone species. Comparisons with other marine invertebrates highlight the specificities of chemical cues and endogenous regulatory mechanisms across relatively closely related taxa

Identification of Candidate Biomarkers for Quality Assessment of Hatchery-reared Mussel Larvae Via GC/MS-based Metabolomics

To ensure environmental and economic sustainability of future aquaculture growth, large-scale hatchery production of mollusc larvae is required. However, variation in larval quality currently limits potential maximum yields. Identification of biomarkers which reflect the immediate physiological condition of larvae during hatchery production could help monitor and determine causes of variation. Metabolomics is well-suited to this task due to its capacity for providing an instantaneous snapshot of the physiology of an organism through analysis of its metabolite profile. As a test, we applied GC/MS-based metabolomics for this purpose. Using a variety of univariate and multivariate feature selection methods, we identified four metabolite–metabolite ratios involving levels of succinate, glycine, alanine, pyroglutamate and myristic acid as candidate biomarkers for assessing mussel larval quality. These metabolites are known to have roles in energy metabolism, osmotic regulation, immune function and cell–cell communication. We anticipate that further investigation of these metabolites and their associated biochemical pathways will yield a more complete understanding of the factors responsible for larval production variability

Putative Involvement of Adrenergic Receptors in Regulation of Mussel (Perna Canaliculus) Larval Settlement

Abstract: Settlement responses were investigated for mussel (Perna canaliculus) larvae after exposure to catecholamines and their precursor metabolites. Settlement and mortality assays were conducted in Petri plates with chemical treatments (L-phenylalanine, L-tyrosine, L-DOPA, dopamine hydrochloride and epinephrine at various concentrations) and controls. The proteinogenic amino acids L-phenylalanine and L-tyrosine were both effective inducers (~65%) of larval settlement at 10⁻⁵ mol l⁻¹ compared with controls (4%). Exposure of larvae to L-DOPA, dopamine and epinephrine resulted in maximum settlement induction (50, 60 and 51%, respectively) at 10⁻⁵ mol l⁻¹. Larval mortalities were low (comparable to controls) across all concentrations of L-phenylalanine and L-tyrosine treatments, whereas high mortalities (>60%) were observed for L-DOPA, dopamine and epinephrine at concentrations ≥ 10⁻⁴ mol l⁻¹. Our results indicate that P. canaliculus larval settlement is under endogenous regulation by a catecholaminergic mechanism. Furthermore, the inductive effects of all tested metabolites in the epinephrine biosynthesis pathway point to a putative involvement of adrenergic-type receptors in the regulation of larval settlement in this mussel species

Mobility, functionality and functional mobility: A review and application for canine veterinary patients

Mobility is an essential aspect of a dog’s daily life. It is defined as the ability to move freely and easily and deviations from an animals’ normal mobility capabilities are often an indicator of disease, injury or pain. When a dog’s mobility is compromised, often functionality (ability to perform activities of daily living; ADL), is also impeded, which can diminish an animal’s quality of life. Given this, it is necessary to understand the extent to which conditions impact a dog’s physiological ability to freely move around their environment to carry out ADL, a concept termed functional mobility. In contrast to human medicine, validated measures of canine functional mobility are currently limited. The aim of this review is to summarise the extent to which canine mobility and functionality are associated with various diseases and how mobility and functional mobility are currently assessed within veterinary medicine. Future work should focus on developing a standardised method of assessing functional mobility in dogs, which can contextualise how a wide range of conditions impact a dog’s daily life. However, for a true functional mobility assessment to be developed, a greater understanding of what activities dogs do on a daily basis and movements underpinning these activities must first be established

Practical Fertilization Procedure and Embryonic Development of the New Zealand Geoduck Clam (Panopea Zelandica)

Copyright © Marine Biological Association of the United Kingdom 2016Cultivation of the geoduck Panopea zelandica (Quoy & Gaimard, 1835) requires knowledge on embryonic development to produce spat in hatcheries. This study investigated the development of P. zelandica embryos at 15°C and 35 ppt and the optimal sperm:egg ratios for fertilization under hatchery conditions. Panopea zelandica broodstock were induced to spawn by serotonin injection. Sperm and eggs were collected and fertilization was conducted at sperm:egg ratios of: 50:1, 100:1, 500:1, 1000:1 and 10,000:1 over 40 min. The optimal sperm:egg ratio was <500:1 and the normal embryo yield at 3 and 18 h post-fertilization (hpf) ranged from 83–96%. Panopea zelandica eggs (~80 μm diameter) developed the first and second polar bodies within 15–20 and 50–55 min post-fertilization, respectively. The blastula appeared at ~8 hpf, including the XR and XL cells and the presumptive shell field depression. Gastrulation occurred at 12–18 hpf with organic material apparent at the shell field depression. The mid-stage trochophore, which appeared at around 35 hpf had an apical plate with an apical tuft. The shell field spread to form the periostracum, which expanded and folded into right and left segments covering the late trochophore. The early D-stage veliger appeared at 45 hpf with the soft body being enclosed by two valves and the appearance of the velum. These observations will serve as the basis for future analyses of P. zelandica embryogenesis and for optimization of commercial production of D-veliger larvae

The cuttlefish Sepia officinalis (Sepiidae, Cephalopoda) constructs cuttlebone from a liquid-crystal precursor

Cuttlebone, the sophisticated buoyancy device of cuttlefish, is made of extensive superposed chambers that have a complex internal arrangement of calcified pillars and organic membranes. It has not been clear how this structure is assembled. We find that the membranes result from a myriad of minor membranes initially filling the whole chamber, made of nanofibres evenly oriented within each membrane and slightly rotated with respect to those of adjacent membranes, producing a helical arrangement. We propose that the organism secretes a chitin-protein complex, which self-organizes layer-by-layer as a cholesteric liquid crystal, whereas the pillars are made by viscous fingering. The liquid crystallization mechanism permits us to homologize the elements of the cuttlebone with those of other coleoids and with the nacreous septa and the shells of nautiloids. These results challenge our view of this ultra-light natural material possessing desirable mechanical, structural and biological properties, suggesting that two self-organizing physical principles suffice to understand its formation.Spanish Ministerio de Ciencia e Innovacion [CGL2010-20748-CO2-01, CGL2013-48247-P, FIS2013-48444-C2-2-P]; Andalusian Consejeria de Innovacion Ciencia y Tecnologia [RNM6433]; (Sepiatech, PROMAR program) of the Portuguese Ministerio da Agricultura e do Mar, Portugal [31.03.05.FEP.002]; Junta de Andalucia [RNM363]; FP7 COST Action of the European Community. [TD0903]info:eu-repo/semantics/publishedVersio

Living with frailty and haemodialysis: a qualitative study

Background: Frailty is highly prevalent in people receiving haemodialysis (HD) and is associated with poor outcomes. Understanding the lived experiences of this group is essential to inform holistic care delivery. / Methods: Semi-structured interviews with N = 25 prevalent adults receiving HD from 3 HD units in the UK. Eligibility criteria included a Clinical Frailty Scale (CFS) score of 4–7 and a history of at least one fall in the last 6 months. Sampling began guided by maximum variation sampling to ensure diversity in frailty status; subsequently theoretical sampling enabled exploration of preliminary themes. Analysis was informed by constructivist grounded theory; later we drew upon the socioecological model. / Results: Participants had a mean age of 69 ± 10 years, 13 were female, and 13 were White British. 14 participants were vulnerable or mildly frail (CFS 4–5), and 11 moderately or severely frail (CFS 6–7). Participants characterised frailty as weight loss, weakness, exhaustion, pain and sleep disturbance arising from multiple long-term conditions. Participants’ accounts revealed: the consequences of frailty (variable function and psychological ill-health at the individual level; increasing reliance upon family at the interpersonal level; burdensome health and social care interactions at the organisational level; reduced participation at the community level; challenges with financial support at the societal level); coping strategies (avoidance, vigilance, and resignation); and unmet needs (overprotection from family and healthcare professionals, transactional health and social care exchanges). / Conclusions: The implementation of a holistic needs assessment, person-centred health and social care systems, greater family support and enhancing opportunities for community participation may all improve outcomes and experience. An approach which encompasses all these strategies, together with wider public health interventions, may have a greater sustained impact. Trial registration: ISRCTN12840463

Composition and screening of antifungal activity against Cladosporium sphaerospermum and Cladosporium cladosporioides of essential oils of leaves and fruits of Piper species

This study investigated the composition and antifungal activity against Cladosporium sphaerospermum and Cladosporium cladosporioides of essential oils of leaves of Piper cernuum, Piper diospyrifolium, Piper crassinervium, Piper solmsianum and Piper umbelata and fruits of P. cernuum and P. diospyrifolium. The essentials oils were analyzed by GC-MS and submitted of the antifungal activity tests. The essential oils of fruits from P. cernuum and leaves of P. crassinervium and P. solmsianum showed potential antifungal activity against C. sphaerospermum and C. cladosporioides. In addition, this is the first report of the composition of essential oils of fruits of P. cernuum and P. diospyrifolium.Key words: Piperaceae, Piper; essential oil composition, antifungal activity, GC-MS