Geographical distribution pattern and interisland movements of Orii’s flying fox in Okinawa Islands, the Ryukyu Archipelago, Japan

The study of mobile animals such as flying foxes in insular habitats involves clarifying the population status on each island and determining the factors affecting movement patterns among the islands in their distributional range. We visited 25 of the Okinawa Islands and documented the number of Orii’s flying foxes Pteropus dasymallus inopinatus from August 2005 to May 2006. We also conducted a monthly road census on the main island (Okinawa-jima Island) and six adjacent islands from June 2006 to January 2007 and counted the number of fruit-bearing trees of the bats’ four main food plants. The results of classification and regression tree analysis suggested that distance from the main island was a primary factor in determining the distribution pattern and population size of this flying fox, whereas island area, number of plant species, and food availability did not directly affect population size. The number of flying foxes on each island tended to decrease with an increase in distance from the main island; no flying foxes existed on islands >30 km away from the main island. On the other hand, the results of the monthly census showed that the population size on each island fluctuated seasonally. Individuals may move between islands in response to seasonal changes in food availability. In conclusion, the distribution and abundance of Orii’s flying foxes in the Okinawa Islands may be determined by the rate of immigration/emigration, depending on each island’s distance from the main island. Seasonal changes in food availability may act as a trigger for interisland movement, but that movement may be restricted by island connectivity.     

Genetic analysis of Hedgehog signaling in ventral body wall development and the onset of omphalocele formation

Background

An omphalocele is one of the major ventral body wall malformations and is characterized by abnormally herniated viscera from the body trunk. It has been frequently found to be associated with other structural malformations, such as genitourinary malformations and digit abnormalities. In spite of its clinical importance, the etiology of omphalocele formation is still controversial. Hedgehog (Hh) signaling is one of the essential growth factor signaling pathways involved in the formation of the limbs and urogenital system. However, the relationship between Hh signaling and ventral body wall formation remains unclear.

Methodology/Principal Findings

To gain insight into the roles of Hh signaling in ventral body wall formation and its malformation, we analyzed phenotypes of mouse mutants of Sonic hedgehog (Shh), GLI-Kruppel family member 3 (Gli3) and Aristaless-like homeobox 4 (Alx4). Introduction of additional Alx4^Lst mutations into the Gli3^Xt/Xt background resulted in various degrees of severe omphalocele and pubic diastasis. In addition, loss of a single Shh allele restored the omphalocele and pubic symphysis of Gli3^Xt/+; Alx4^Lst/Lst embryos. We also observed ectopic Hh activity in the ventral body wall region of Gli3^Xt/Xt embryos. Moreover, tamoxifen-inducible gain-of-function experiments to induce ectopic Hh signaling revealed Hh signal dose-dependent formation of omphaloceles.

Conclusions/Significance

We suggest that one of the possible causes of omphalocele and pubic diastasis is ectopically-induced Hh signaling. To our knowledge, this would be the first demonstration of the involvement of Hh signaling in ventral body wall malformation and the genetic rescue of omphalocele phenotypes.     

The role of selective transport in neuronal polarization

Neurons are functionally and morphologically polarized and possess two distinct types of neurites: axons and dendrites. Key molecules for axon formation are transported along microtubules and accumulated at the distal end of the nascent axons. In this review, we summarize recent advances in the understanding of the mechanisms involved in selective transport in neurons. In addition, we focus on motor proteins, cargo, cargo adaptors, and the loading and unloading of cargo.     

Flexible search for single-axon morphology during neuronal spontaneous polarization

Polarization, a disruption of symmetry in cellular morphology, occurs spontaneously, even in symmetrical extracellular conditions. This process is regulated by intracellular chemical reactions and the active transport of proteins and it is accompanied by cellular morphological changes. To elucidate the general principles underlying polarization, we focused on developing neurons. Neuronal polarity is stably established; a neuron initially has several neurites of similar length, but only one elongates and is selected to develop into an axon. Polarization is flexibly controlled; when multiple neurites are selected, the selection is eventually reduced to yield a single axon. What is the system by which morphological information is decoded differently based on the presence of a single or multiple axons? How are stability and flexibility achieved? To answer these questions, we constructed a biophysical model with the active transport of proteins that regulate neurite growth. Our mathematical analysis and computer simulation revealed that, as neurites elongate, transported factors accumulate in the growth cone but are degraded during retrograde diffusion to the soma. Such a system effectively works as local activation-global inhibition mechanism, resulting in both stability and flexibility. Our model shows good accordance with a number of experimental observations.     

Evaluation of cellular influences of platinum nanoparticles by stable medium dispersion

Platinum nanoparticles have industrial application, for example in catalysis, and are used in consumer products such as cosmetics and supplements. Therefore, among the many nanoparticles, platinum is one of the more accessible nanoparticles for consumers. Most platinum nanoparticles that are used in cosmetics and supplements which have an anti-oxidant activity are modified particles. However, the cellular influences of pristine platinum nanoparticles are still unclear, although it has been reported that platinum nanoparticles induce oxidative stress. In this study, we investigated the cellular influences induced by pure pristine platinum nanoparticles. Platinum nanoparticles of 100% purity were dispersed in a cell culture medium and stable medium dispersion was obtained. The platinum nanoparticle medium dispersion was applied to two kinds of cultured cells, A549 and HaCaT cells, and the cellular influences were examined. Cell viability (MTT assay), cell proliferation (clonogenic assay), apoptosis induction (caspase-3 activity), intracellular ROS level (DCFH assay), and lipid peroxidation level (DPPP assay) were measured as markers of cellular influences. Transmission electron microscope observation showed cellular uptake of platinum nanoparticles. However, the platinum nanoparticles did not drive any markers. It is known that some metal oxide nanoparticles such as NiO and CuO show severe cytotoxicity via metal ion release. Compared with these toxic nanoparticles, the platinum nanoparticles used in this study did not release platinum ions into the culture media. These results suggest that the physically and chemically inactive cellular influences of platinum nanoparticles are small.     

Effect of linear polarized near-infrared light irradiation and light exercise on muscle performance

This study aimed to determine the effect of active warm-up by local muscle light exercise and passive warm-up by polarized light irradiation on skin and muscle temperatures and forearm muscle performance (muscle strength, power, endurance, and controlled force-exertion). Ten healthy males performed various grip tests before and after active (local muscle light exercise) and passive (linear polarized near-infrared light irradiation) warm-ups. An active warm-up involved intermittent gripping exercise (contraction: 1 second and relaxation: 1 second) for 10 minutes using a sponge. A passive warm-up consisted of polarized light irradiation to the forearm (superficial digital flexor) for 10 minutes (irradiation: 5 seconds and rest: 1 second). Skin and muscle temperatures were measured during both warm-ups. Skin and muscle temperatures increased significantly after 5 minutes of local muscle light exercise and after 10 minutes of polarized light irradiation. Temperatures were significantly higher after 6 minutes of local muscle light exercise than after 6 minutes of polarized light irradiation. There were no significant differences of muscle strength, power, and controlled force-exertion before and after either warm-up. Average force outputs in all conditions significantly decreased with exertion time, and at 30, 60, 90, and 120 seconds they were higher in both warm-up conditions than in the non-warm-up condition. In conclusion, both warm-ups may contribute to improve muscle endurance performance in the decreasing force phase.     

Rapid evolution of coral proteins responsible for interaction with the environment

BACKGROUND: Corals worldwide are in decline due to climate change effects (e.g., rising seawater temperatures), pollution, and exploitation. The ability of corals to cope with these stressors in the long run depends on the evolvability of the underlying genetic networks and proteins, which remain largely unknown. A genome-wide scan for positively selected genes between related coral species can help to narrow down the search space considerably. METHODOLOGY/PRINCIPAL FINDINGS: We screened a set of 2,604 putative orthologs from EST-based sequence datasets of the coral species Acropora millepora and Acropora palmata to determine the fraction and identity of proteins that may experience adaptive evolution. 7% of the orthologs show elevated rates of evolution. Taxonomically-restricted (i.e. lineage-specific) genes show a positive selection signature more frequently than genes that are found across many animal phyla. The class of proteins that displayed elevated evolutionary rates was significantly enriched for proteins involved in immunity and defense, reproduction, and sensory perception. We also found elevated rates of evolution in several other functional groups such as management of membrane vesicles, transmembrane transport of ions and organic molecules, cell adhesion, and oxidative stress response. Proteins in these processes might be related to the endosymbiotic relationship corals maintain with dinoflagellates in the genus Symbiodinium. CONCLUSION/RELEVANCE: This study provides a birds-eye view of the processes potentially underlying coral adaptation, which will serve as a foundation for future work to elucidate the rates, patterns, and mechanisms of corals' evolutionary response to global climate change.     

A novel homocysteine-responsive gene, smap8, modulates mitogenesis in rat vascular smooth muscle cells.

We isolated the cDNA of a gene, designated smooth muscle-associated protein 8 (smap8), during a search for new genes expressed in human aortic smooth muscle cells. The full-length smap8 cDNA is 3241 bp long and contains an open reading frame of 1113 bp encoding an approximately 45 kDa soluble protein identical to NDRG4 protein. Smap8 mRNA was expressed predominantly in the brain and heart, and moderately in vascular smooth muscle cells. Expression of smap8 mRNA was induced within 3-12 h by treatment with 10 mm homocysteine in rat aortic smooth muscle cells (A10 cells). Expression of exogenous smap8 markedly reduced both the proliferation and migration rates of rat A10 cells, however, PDGF-induced proliferation was significantly enhanced in smap8-expressed cells compared with mock-transfected cells. To ascertain the involvement of smap8 in mitogenesis, we tested the effects of stimulation of smap8, MEK1/2 or ERK1/2, which is known as a proliferation relating intermediate, by various growth factors and cytokines. PDGF was the most prominent in promoting phosphorylation of the smap8 protein. PDGF-dependent phosphorylation of smap8 was induced prior to ERK1/2 activation, and was repressed by staurosporine, a general inhibitor of serine/threonine kinases. Furthermore, activation of both MEK1/2 and ERK1/2 was markedly enhanced in these cells. Smap8 might therefore regulate the potentiation of ERK1/2 signalling induced by PDGF treatment. Our results imply that smap8 is involved in the regulation of mitogenic signalling in vascular smooth muscle cells, possibly in response to a homocysteine-induced injury.     

Effect of traditional floor sitting on postural control after standing

Seiza is a Japanese traditional floor sitting style, sitting down with both legs set at about a 180 degree angle and both femurs on both lower legs. We examined the influence of the somatic dysesthesia and decrease in voluntary toe flexion strength (VTF) induced by Seiza on the center of pressure (COP) sway. Fifteen adults participated in this experiment. COP Sway was measured immediately after a chair resting (pre-test), when a plantar dysethesia occurred (post-test A), and when a decrease (under 30% of maximal voluntary contraction (MVC)) in the VTF set in (post-test B). Tissue oxygenation kinetics in the soleus muscle and plantar somatosensory thresholds (ST) were measured just before each COP test and during Seiza. From starting Seiza, oxygenated hemoglobin/myoglobin decreased markedly and reached a plateau within about 6 min. ST abruptly increased at about 19 min from starting Seiza. VTF decreased to less than 30% MVC in 33% of the participants after 10 min from the acute increase in ST, and in 100% after 20 min. When sustaining Seiza for 19 min, ST rose and sway velocity and antero-posterior sway increased. With continued Seiza, VTF decreased to below 30% MVC at 10 - 20 min, and the above stated body sway further markedly increase.