Large-scale recording of neurons by movable silicon probes in behaving rodents

A major challenge in neuroscience is linking behavior to the collective activity of neural assemblies. Understanding of input-output relationships of neurons and circuits requires methods with the spatial selectivity and temporal resolution appropriate for mechanistic analysis of neural ensembles in the behaving animal, i.e. recording of representatively large samples of isolated single neurons. Ensemble monitoring of neuronal activity has progressed remarkably in the past decade in both small and large-brained animals, including human subjects. Multiple-site recording with silicon-based devices are particularly effective because of their scalability, small volume and geometric design. Here, we describe methods for recording multiple single neurons and local field potential in behaving rodents, using commercially available micro-machined silicon probes with custom-made accessory components. There are two basic options for interfacing silicon probes to preamplifiers: printed circuit boards and flexible cables. Probe supplying companies (http://www.neuronexustech.com/; http://www.sbmicrosystems.com/; http://www.acreo.se/) usually provide the bonding service and deliver probes bonded to printed circuit boards or flexible cables. Here, we describe the implantation of a 4-shank, 32-site probe attached to flexible polyimide cable, and mounted on a movable microdrive. Each step of the probe preparation, microdrive construction and surgery is illustrated so that the end user can easily replicate the process.     

Phytosulfokine stimulates somatic embryogenesis in Cryptomeria japonica

Phytosulfokine (PSK), which has been identified as a plant growth factor, had a dramatic stimulatory effect on the formation of somatic embryos of sugi (Cryptomeria japonica) in the presence of polyethylene glycol. The resultant somatic embryos germinated with synchronous sprouting of cotyledons, hypocotyls and roots, and most of the seedlings grew normally. A cDNA clone for the precursor to the PSK peptide of C. japonica was identified in an expressed sequence tags database. Our results support the existence of a PSK signaling pathway in C. japonica.     

Seedling establishment of deciduous trees in various topographic positions

Abstract. We investigated the effect of topography‐related environmental factors (i.e., ground‐surface stability and soil moisture) on seedling establishment of 8 deciduous tree species. A field experiment was carried out using canopy species, which were classified into 3 groups based on the spatial distribution of adult trees (ridge, slope and valley). Demographic parameters were compared among species during the early stage of seedling establishment among 3 topographic positions in combination with gap and canopy conditions. The percentage of emerging seedlings tended to be lower on the ridge irrespective of the adult topographical distribution patterns. There was no clear trend in seedling emergence among the species groups classified by their spatial distribution. Seedling survival during 2 growing seasons was significantly different among species, topographic positions and light conditions. On the ridge, seedlings of the species dominating ridge tops had greater survival than those of other species, probably due to differences in demand for soil moisture. On the slope, frequent physical damage caused by surface material movement was observed and some species showed greater adaptability to the disturbed slope habitat. Survival of all seedlings was highest in the valley plots. Light conditions were the critical factor for seedling survival in some species. The results of this study suggest that topography creates diverse habitats for the establishment of tree seedlings. In addition to soil moisture, surface material movement may be a significant factor affecting seedling establishment.     

Some observations on the solitary male among Japanese monkeys

The social behavior pattern of a solitary male at Koshima was studied by means of radio-telemetry. The relationship between the solitary males and the troop was estimated from radio-tracking data of the former's location and movement, and by direct observation of the latter at each corresponding hour.For most of day, the solitary male stayed within a distance of about 20 to 150 m from the central part of the troop, occasionally approaching it. His movement also was synchronized with that of the troop. For two nights, the solitary male slept at places which were about 200 m from the sleeping sites of the troop and faced them across the beach. The relationship between the solitary male and the troop did not seem to be strongly antagonistic.It can be assumed that the solitary male was moving according to certain pre-determined relationships or social contacts with the troop. The example of this solitary male shows the existence of the solitary male that follows and maintains contact with the troop, even outside the copulatory season.This study was sponsored by Scientific Research Grant No. 91620 of the Ministry of Education to the Japan Monkey Centre.     

Distribution of Zearalenone-Producing Fusarium Species in Japan

One hundred sixty-six isolates of Fusarium spp. from domestic cereal grains, feed, and other sources were examined for their ability to produce zearalenone on autoclaved moist rice grains. They belonged to the following species (number of producers/number tested): F. roseum (9/28), F. roseum (Culmorum) (3/4), F. roseum (Gibbosum) (2/5), F. roseum (Avenaceum) (1/2), F. roseum (Scirpi) (0/1), F. tricinctum (1/4), F. tricinctum (Sporotrichiella) (0/7), F. lateritium (1/1), F. episphaeria (0/2), F. moniliforme (0/3), F. oxysporum (0/12), F. rigidiusculum (0/4), F. solani (0/4), F. splendens (0/1), F. nivale (0/2), and Fusarium spp. (15/86). Zearalenone was isolated from molded rice by ethanol extraction and purified by column chromatography. Selected isolates of F. roseum M-3-2 and F. roseum (Gibbosum) A-O-2 produced 50 to 100 mg of zearalenone per kg of rice. Increased yields (250 to 407 mg/kg of rice) were obtained by F. roseum M-3-2 when the substrate was supplemented with 1% peptone.     

A Novel Nectin-mediated Cell Adhesion Apparatus That Is Implicated in Prolactin Receptor Signaling for Mammary Gland Development

Mammary gland development is induced by the actions of various hormones to form a structure consisting of collecting ducts and milk-secreting alveoli, which comprise two types of epithelial cells known as luminal and basal cells. These cells adhere to each other by cell adhesion apparatuses whose roles in hormone-dependent mammary gland development remain largely unknown. Here we identified a novel cell adhesion apparatus at the boundary between the luminal and basal cells in addition to desmosomes. This apparatus was formed by the trans-interaction between the cell adhesion molecules nectin-4 and nectin-1, which were expressed in the luminal and basal cells, respectively. Nectin-4 of this apparatus further cis-interacted with the prolactin receptor in the luminal cells to enhance the prolactin-induced prolactin receptor signaling for alveolar development with lactogenic differentiation. Thus, a novel nectin-mediated cell adhesion apparatus regulates the prolactin receptor signaling for mammary gland development.     

Synthesis and evaluation of novel pyrimidine-based dual EGFR/Her-2 inhibitors

A structure-activity relationship study of 4-anilinopyrimidines for dual EGFR/Her-2 inhibitor has resulted in the identification of 4-anilino-5-alkenyl or 5-alkynyl-6-methylpyrimidine derivatives that have exhibited effective inhibitory activity against both enzymes. The presence of 5-alkenyl or 5-alkynyl moiety bearing terminal hydrophilic group played important role for inhibition of these enzymes. Selected compounds in the series demonstrated some activity against Her-2 dependent cell line (BT474).     

Lucidenic acids-rich extract from antlered form of Ganoderma lucidum enhances TNFα induction in THP-1 monocytic cells possibly via its modulation of MAP kinases p38 and JNK

The Ganoderma lucidum (G. lucidum) is one of the oriental fungi that has been reported to have immunomodulatory properties. Although effect of β-glucans from G. lucidum has been well documented, little is known about how other major bioactive components, the triterpenes, contribute to the immunomodulatory function of G. lucidum. Here, we showed that triterpenes-rich extract of antlered form of G. lucidum (G. lucidum AF) induces TNFα production in monocytic THP-1 cells. Furthermore, the extract also synergized with lipopolysaccharide (LPS) to induce TNFα production in THP-1 cells, suggesting an immunostimulatory role of triterpenes-rich extract of G. lucidum AF. Notably, the extract enhanced LPS-induced phosphorylation of p38 mitogen-activated protein kinase (MAPK), while it suppressed LPS-induced phosphorylation of c-Jun N-terminal kinase (JNK) MAPK. p38 Inhibitor suppressed TNFα production, while JNK inhibitor enhanced TNFα production, implying that synergistic effect of the extract may work by modulating p38 and JNK MAPKs. Moreover, we found that the triterpenes-rich extract of G. lucidum AF contains high amounts of lucidenic acids. Lucidenic acid-A, -F and -D₂, which seem to dominantly exist in the extract, were purified from the triterpenes-rich extract. We also identified Lucidenic acid-A and -F as modulators of JNK and p38, respectively. Thus, our data demonstrate that lucidenic acids-rich extract from G. lucidum AF enhances LPS-induced immune responses in monocytic THP-1 cells possibly via the modulation of p38 and JNK MAPKs activation.     

Queen-specific volatile in a higher termite Nasutitermes takasagoensis (Isoptera: Termitidae)

In social insect colonies, queen-produced pheromones have important functions in social regulation. These substances influence the behavior and physiology of colony members. A queen-produced volatile that inhibits differentiation of new neotenic reproductives was recently identified in the lower termite Reticulitermes speratus. However, there are no known queen-specific volatiles of this type in any other termite species. Here, we report volatile compounds emitted by live queens of the higher termite Nasutitermes takasagoensis. We used headspace gas chromatography mass spectroscopy (HS GC-MS) to analyze volatiles emitted by live primary queens, workers, soldiers, alates, and eggs collected in a Japanese subtropical forest. Among 14 detected compounds, 7 were soldier-specific, 1 was alate-specific, 1 was egg-specific, and 1 was queen-specific. The queen-specific volatile was phenylethanol, which is different than the compound identified in R. speratus. The identification of this queen-specific volatile is the first step in determining its functions in higher termite social regulation. Comparisons of queen pheromone substances regulating caste differentiation among various termite taxa will contribute to a better understanding of the evolution of social systems in termites.     

Spawning and fertility of F<Subscript>1</Subscript> hybrids of the coral genus <Emphasis Type="Italic">Acropora</Emphasis> in the Indo-Pacific

The role of hybridization through multi-specific synchronous spawning in the evolution of reef-building corals has been discussed since the 1990s, particularly for the genus Acropora. However, F₁ hybrids have been reported as common in only one case in the Caribbean, with no evidence of mechanisms that would allow continuous reproduction of the hybrids. In this study, we report for the first time the fecundity of two F₁ hybrid colonies produced experimentally from two Indo-Pacific species, A. intermedia and A. florida. These F₁ hybrids spawned at the same time as the parental corals. Backcrossing and F₁ hybrid crossing were successful in both directions. Furthermore, more than 90% self-fertilization was achieved in an F₁ hybrid, although it was negligible in the parental corals. While it is possible that the F₁ hybrid was a chimera, these results suggest that some products of interspecific hybridization may persist as the offspring of self-fertilizing F₁ hybrids.