Phagocytic Ability of Oyster Hemocytes Measured by a Simple Method Using Bacterial Thin-layer

A simple method called the phagocytic plaque assay was used to visually present and estimate the phagocytic ability of the hemocytes from the giant Pacific oyster, Crassostrea gigas, using adherent Staphylococcus aureus cells on a plastic dish. Many plaques appeared on the bacterial thin-layer when the oyster hemocytes were overlaid and incubated on killed cells of S. aureus. At both 20℃ and 30℃, the phagocytic ability of the oyster hemocytes were more activated with a significantly larger average area of plaques than were the hemocytes at 10℃. This method was considered to be practical and effective evaluating the qualification of phagocytosis by the oyster hemocytes, however, some problems for the quantification analysis still remain to be solved

Pharmacology and Molecular Identity of Serotonin Receptor in Bivalve Mollusks

It is now known that 5-HT regulates several neurobehavioral systems such as mood, appetite, sleep, learning, and memory. It also plays critical roles in the physiological functions of peripheral organs involved in stress, growth, and reproduction in the animal kingdom. 5-HT content has seen to be higher in the nervous system of bivalves than those of other examined invertebrates and vertebrates. Thus, bivalves have been considered as an excellent model to investigate 5-HT functions in neurological and peripheral systems. The present study reviews knowledge on 5-HT signaling mediated through 5-HT receptor and its physiological contribution to regulate reproduction in bivalves. Two G-protein-coupled 5-HT1-like receptors have been cloned in bivalve species. However, binding affinities of the 5-HT agonists and antagonists to the isolated plasma membrane proteins and their effects on spawning in bivalves suggest the presence of a single or mixed 5-HT1-, 5-HT2-, and 5-HT3-like receptors. It has suggested that the 5-HT-like receptors in bivalves are distinct from those of mammalian 5-HT receptors due to pharmacological properties. The present review pays a special attention to future research perspectives to better understand 5-HT regulation of reproduction in bivalves, which can provide us with satisfactory knowledge to elucidate reproductive disorders associated with dysfunctions of the neurotransmitter system

Structure-Function of Serotonin in Bivalve Molluscs

It has been observed that 5-HT excites the heart nerves in hard clam and regulates contraction and relaxation of the anterior byssus retractor muscle in the blue mussel. It is now known that 5-HT regulates several neurobehavioral systems such as mood, appetite, sleep, learning, and memory. It also plays critical roles in the physiological functions of peripheral organs involved in stress, growth, and reproduction in the animal kingdom. The present study reviews conserved 5-HT biosynthesis and its localization in the nervous system, and its physiological contribution to regulate reproduction in bivalves. In the cytosol of neurons, tryptophan hydroxylase catalyzes hydroxylation of l-tryptophan to 5-hydroxytryptophan, which is converted to 5-HT by aromatic l-amino acid decarboxylase. A 5-HT transporter and a monoamine oxidase reuptakes and metabolizes 5-HT to control the amount of released 5-HT in the nervous system and peripheral organs. Perikarya and fibers of 5-HT neurons are mostly located in the cortices and neuropil of ganglia, respectively, and innervate the gonad. However, distribution and 5-HT content differ among species and sexes and undergo seasonal variations associated with gonadal development. The present review pays a special attention to future research perspectives to better understand 5-HT regulation of reproduction in bivalves

Induction and Enhancement of Cardiac Cell Differentiation from Mouse and Human Induced Pluripotent Stem Cells with Cyclosporin-A

Induced pluripotent stem cells (iPSCs) are novel stem cells derived from adult mouse and human tissues by reprogramming. Elucidation of mechanisms and exploration of efficient methods for their differentiation to functional cardiomyocytes are essential for developing cardiac cell models and future regenerative therapies. We previously established a novel mouse embryonic stem cell (ESC) and iPSC differentiation system in which cardiovascular cells can be systematically induced from Flk1+ common progenitor cells, and identified highly cardiogenic progenitors as Flk1+/CXCR4+/VE-cadherin− (FCV) cells. We have also reported that cyclosporin-A (CSA) drastically increases FCV progenitor and cardiomyocyte induction from mouse ESCs. Here, we combined these technologies and extended them to mouse and human iPSCs. Co-culture of purified mouse iPSC-derived Flk1+ cells with OP9 stroma cells induced cardiomyocyte differentiation whilst addition of CSA to Flk1+ cells dramatically increased both cardiomyocyte and FCV progenitor cell differentiation. Spontaneously beating colonies were obtained from human iPSCs by co-culture with END-2 visceral endoderm-like cells. Appearance of beating colonies from human iPSCs was increased approximately 4.3 times by addition of CSA at mesoderm stage. CSA-expanded human iPSC-derived cardiomyocytes showed various cardiac marker expressions, synchronized calcium transients, cardiomyocyte-like action potentials, pharmacological reactions, and ultra-structural features as cardiomyocytes. These results provide a technological basis to obtain functional cardiomyocytes from iPSCs

Quantum state preparation and macroscopic entanglement in gravitational-wave detectors

Long-baseline laser-interferometer gravitational-wave detectors are operating at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within a broad frequency band. Such a low classical noise budget has already allowed the creation of a controlled 2.7 kg macroscopic oscillator with an effective eigenfrequency of 150 Hz and an occupation number of 200. This result, along with the prospect for further improvements, heralds the new possibility of experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical behavior of objects in the realm of everyday experience - using gravitational-wave detectors. In this paper, we provide the mathematical foundation for the first step of a MQM experiment: the preparation of a macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum state, which is possible if the interferometer's classical noise beats the SQL in a broad frequency band. Our formalism, based on Wiener filtering, allows a straightforward conversion from the classical noise budget of a laser interferometer, in terms of noise spectra, into the strategy for quantum state preparation, and the quality of the prepared state. Using this formalism, we consider how Gaussian entanglement can be built among two macroscopic test masses, and the performance of the planned Advanced LIGO interferometers in quantum-state preparation

Searching for a Stochastic Background of Gravitational Waves with LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is $\Omega_{\rm GW} < 6.5 \times 10^{-5}$. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure