Knockdown of zebrafish Nav1.6 sodium channel impairs embryonic locomotor activities

[[abstract]]Although multiple subtypes of sodium channels are expressed in most neurons, the specific contributions of the individual sodium channels remain to be studied. The role of zebrafish Nav1.6 sodium channels in the embryonic locomotor movements has been investigated by the antisense morpholino (MO) knockdown. MO1 and MO2 are targeted at the regions surrounding the translation start site of zebrafish Nav1.6 mRNA. MO3 is targeted at the RNA splicing donor site of exon 2. The correctly spliced Nav1.6 mRNA of MO3 morphants is 6% relative to that of the wild-type embryos. Nav1.6-targeted MO1, MO2 and MO3 attenuate the spontaneous contraction, tactile sensitivity, and swimming in comparison with a scrambled morpholino and mutated MO3 morpholino. No significant defect is observed in the development of slow muscles, the axonal projection of primary motoneurons, and neuromuscular junctions. The movement impairments caused by MO1, MO2, and MO3 suggest that the function of Nav1.6 sodium channels is essential on the normal early embryonic locomotor activities.[[notice]]補正完畢[[journaltype]]國

Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations

Derogation of Competitors

Verbal signals are sometimes used to manipulate the impressions that people form about oneself and others. For the goal of self-enhancement, one can manipulate impressions either by elevating oneself or by derogating others. Five hypotheses about derogation of same-sex competitors were generated from an evolutionary model of human-mate competition. These hypotheses focused on sex differences in the importance that humans attach to external resources, rank, achievements, physical prowess, reproductive value and fidelity. Four studies were conducted to test these hypotheses. In a preliminary study (N = 80), subjects nominated intrasexual derogation tactics they had previously observed. Study 1 (N = 120) examined estimates of the likelihood that men and women would perform each tactic. Study 2 (N = 101) identified the perceived effectiveness of each derogation tactic for men and women. Study 3 (N = 100) used act reports based on self-recording and observer-recording to identify the likelihood of specific persons performing each derogation tactic. Although there were variations across studies and several anomalies, results generally supported the hypotheses based on an evolutionary model of human intrasexual mate competition. Discussion focuses on the importance of discourse and impression manipulation in the evolution of human competition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69020/2/10.1177_0265407590073006.pd