Mapping of neuropeptide Y expression in Octopus brains

Neuropeptide Y (NPY) is an evolutionarily conserved neurosecretory molecule implicated in a diverse complement of functions across taxa and in regulating feeding behavior and reproductive maturation in Octopus. However, little is known about the precise molecular circuitry of NPY-mediated behaviors and physiological processes, which likely involve a complex interaction of multiple signal molecules in specific brain regions. Here, we examined the expression of NPY throughout the Octopus central nervous system. The sequence analysis of Octopus NPY precursor confirmed the presence of both, signal peptide and putative active peptides, which are highly conserved across bilaterians. In situ hybridization revealed distinct expression of NPY in specialized compartments, including potential “integration centers,” where visual, tactile, and other behavioral circuitries converge. These centers integrating separate circuits may maintain and modulate learning and memory or other behaviors not yet attributed to NPY-dependent modulation in Octopus. Extrasomatic localization of NPY mRNA in the neurites of specific neuron populations in the brain suggests a potential demand for immediate translation at synapses and a crucial temporal role for NPY in these cell populations. We also documented the presence of NPY mRNA in a small cell population in the olfactory lobe, which is a component of the Octopus feeding and reproductive control centers. However, the molecular mapping of NPY expression only partially overlapped with that produced by immunohistochemistry in previous studies. Our study provides a precise molecular map of NPY mRNA expression that can be used to design and test future hypotheses about molecular signaling in various Octopus behaviors.     

Statistical Limitations on Molecular Evolution

Abstract

Complexity of functions evolving in an evolution process are expected to be limited by the time length of an evolution process among other factors. This paper outlines a general method of deriving function-complexity limitations based on mathematical statistics and independent from details of a biological or genetic mechanism of the evolution of the function. Limitations on the emergence of life are derived, these limitations indicate a possibility of a very fast evolution and are consistent with “RNA world” hypothesis. The discussed method is general and can be used to characterize evolution of more specific biological organism functions and relate functions to genetic structures. The derived general limitations indicate that a co-evolution of multiple functions and species could be a slow process, whereas an evolution of a specific function might proceed very fast, so that no trace of intermediate forms (species) is preserved in fossil records of phenotype or DNA structure; this is consistent with a picture of “punctuated equilibrium”.     

Efficient tuning of potential parameters for liquid–solid interactions

Spherical and cylindrical water droplets on silicon surface are studied to tune the silicon–oxygen interaction. We use molecular dynamics simulations to estimate the contact angle of two different shaped droplets. We found that the cylindrical droplets are independent of the line tension as their three phases curvature is equal zero. Additionally, we compare an analytical model, taking into account or not the Tolman length and we show that for spherical small size droplets, this length is important to be included, in contrast to cylindrical droplets in which the influence of the Tolman length is negligible. We demonstrate that the usual convenient way to exclude linear tension in the general case can give wrong results. Here, we consider cylindrical droplets, since their contact angle does not depend on the droplet size in the range of few to 10ths of nanometres. The droplets are stabilised due to the periodic boundary conditions. This allows us to propose a new parameterisation for nanoscale droplets, which is independent the size of the droplets or its shape, minimising at the same time the calculation procedure. With the proposed methodology, we can extract the epsilon parameter of the interaction potential between a liquid and a solid from the nanoscaled molecular simulation with only as input the macrosized experimental wetting angle for a given temperature.     

Vague-to-crisp dynamics of percept formation modeled as operant (selectionist) process

We model the vague-to-crisp dynamics of forming percepts in the brain by combining two methodologies: dynamic logic (DL) and operant learning process. Forming percepts upon the presentation of visual inputs is likened to model selection based on sampled evidence. Our framework utilizes the DL in selecting the correct “percept” among competing ones, but uses an intrinsic reward mechanism to allow stochastic online update in lieu of performing the optimization step of the DL framework. We discuss the connection of our framework with cognitive processing and the intentional neurodynamic cycle.     

973. DENDROBIUM HEKOUENSE

Dendrobium hekouense Z.J. Liu & L.J. Chen is illustrated. Its distribution, ecology and successful cultivation are described.     

Synthesis of 6-Aza- & 6-Methyl-pyrimidine Ribonucleoside Phosphoramidites and Their Incorporation in Hammerhead Ribozymes

Abstract

The synthesis of phosphoramidites of 6-modified pyrimidine ribonucleosides and their incorporation into hammerhead ribozymes and influence on nuclease stability and catalytic activity is described.     

New Structural Motifs for Hammerhead Ribozymes. Catalytic Activity of Abasic Nucleotide Substituted Ribozymes

Abstract

The synthesis of 1-deoxy-D-ribofuranose-3-(2-cyanoethyl N,N-diisopropylphosphoramidite) (6) from D-ribose and its incorporation into a hammerhead ribozyme is described.