Phenetic diversity in the <Emphasis Type="Italic">Fritillaria camschatcensis</Emphasis> population grown on the Sapporo campus of Hokkaido University

Triploid Fritillaria camschatcensis (L.) Ker-Gawler (2n = 3x = 36) is a wild species growing in the low-lying areas of Hokkaido Island, Japan, including the Sapporo campus of Hokkaido University. Many F. camschatcensis plants grew on the campus about a century ago, but we seldom find the plants nowadays and so a project to restore this species is being planned. Because preservation of genetic diversity and composition in populations has become a major target of conservation, this study compared variation in the F. camschatcensis population on the Sapporo campus with that in two other populations in Hokkaido. Phenetic variation assessed by 57 randomly amplified polymorphic DNA markers showed that the three populations were significantly distinct from each other; analysis of molecular variance showed 64.3% of variation (P < 0.001) existed among the three populations. Comparison of phenetic diversity on the Sapporo campus population with that in the two other populations showed that the Sapporo campus population contained large genetic variation despite reduced plant numbers. These results indicate that multiplying F. camschatcensis individuals on the Sapporo campus is adequate to restore the Sapporo campus population because this population contains enough genetic diversity, and that transplanting from other populations should be avoided so as not to introduce different genotypes into the campus. These results will be used to design the restoration strategy.     

Development and Characterization of Enteric-Coated Immediate-Release Pellets of Aceclofenac by Extrusion/Spheronization Technique Using κ-Carrageenan as a Pelletizing Agent

In the present study, an attempt was made to prepare immediate-release enteric-coated pellets of aceclofenac, a poorly soluble nonsteroidal anti-inflammatory drug that has a gastrointestinal intolerance as its serious side effect. Formulation of enteric-coated pellets with improved solubility of aceclofenac could address both of these problems. To achieve these goals, pellets were prepared by extrusion–spheronization method using pelletizing agents that can contribute to the faster disintegration and thereby improve the solubility of the drug. Different disintegrants like β-cyclodextrin, kollidon CL, Ac-Di-Sol, and sodium starch glycolate were tried in order to further improve disintegration time. The pellets were characterized for drug content, particle size distribution, flow properties, infrared spectroscopy, surface morphology, disintegration rate, and dissolution profile. The formulations, which showed best disintegration and dissolution profiles, were coated with Eudragit L100-55, an enteric-coated polymer which does not dissolve at gastric pH but dissolves at intestinal pH, releasing the drug immediately in the dissolution medium. The optimized enteric-coated formulation containing 20% κ-carrageenan, lactose, and sodium starch glycolate as a disintegrant did inhibit the release of the drug for 2 h in 0.1 N HCl, whereas 87% of the drug was released within 45 min. The improvement was substantial when it was compared with solubility of pure drug under the same conditions. Thus, dissolution profiles suggested that combination of κ-carrageenan and sodium starch glycolate resulted into fast-disintegrating, immediate-release pellets, overcoming the bioavailability problem of the poorly soluble drug, aceclofenac, and enteric coating of these pellets avoids the exposure of aceclofenac to ulcer-prone areas of the gastrointestinal tract.     

Observation of brown-throated three-toed sloths: mating behaviour and the simultaneous nurturing of two young

Bradypus variegatus is a member of the Order Pilosa, Family Bradypodidae, and is distributed in many subtropical and tropical countries in South and Central America. However, studies on this species in the wild are relatively limited and many aspects of its reproductive behaviour are unknown or unclear. The current report presents new observations of the reproductive behaviour of B. variegatus in its natural environment. These include details of both a male–female copulation and the simultaneous nurturing of two young sloths.     

Chronic Administration of Lamotrigine Downregulates COX-2 mRNA and Protein in Rat Frontal Cortex

Chronic administration to rats of mood-stabilizers that are effective against mania in bipolar disorder, is reported to downregulate markers of the brain arachidonic acid cascade. We hypothesized that chronic administration of lamotrigine, which is used to treat depression and rapid cycling in bipolar disorder, might do so as well. Male CDF rats were administered a therapeutically relevant dose of lamotrigine (10 mg/kg) or vehicle intragastrically once daily for 42 days. Protein levels of isoforms of phospholipase A₂ (PLA₂) and of cyclooxygenase (COX), and the mRNA level of COX-2, were quantified in the frontal cortex using immunoblotting and RT-PCR, respectively. Compared to vehicle-treated rats, chronic lamotrigine significantly decreased frontal cortex protein and mRNA levels of COX-2 without altering protein levels of the PLA₂ isoforms. Consistent with the hypothesis, lamotrigine and other mood-stabilizers have a common downregulatory action on COX-2 expression in rat brain, which may account in part for their efficacy in bipolar disorder.     

Growth Inhibition of <Emphasis Type="Italic">Streptococcus mutans</Emphasis> with Low Xylitol Concentrations

No studies on the concentration dependency of the inhibition of Streptococcus mutans with xylitol are available. We studied xylitol-induced growth inhibition of two type strains, S. mutans NCTC 10449 and Ingbritt, and three clinical isolates of S. mutans. The strains were grown in Brain Hearth Infusion Medium in the presence of 0.001% (0.066 mM), 0.005% (0.33 mM), 0.01% (0.66 mM), 0.1% (6.6 mM), and 1% (66 mM) xylitol. Growth was followed by measuring the absorbance at a wavelength of 660 nm. The highest xylitol concentration tested in this study, 1%, showed mean inhibition percentages ranging from 61% to 76% when the growth inhibition of the five strains was compared to the control without xylitol at log-phase. For 0.1% xylitol, the inhibition percentages ranged from 22% to 59%. A concentration dependency was seen in the growth inhibition, with 0.01% xylitol being the lowest xylitol concentration inhibiting all five strains significantly (p < 0.001). The growth inhibition percentages determined for 0.01% xylitol, however, were low, and the inhibition was significantly weaker as compared to 0.1% and 1% xylitol. Our results suggest that low xylitol concentrations of 0.1% (6.6 mM) could inhibit mutans streptococci in vivo but even lower xylitol concentrations may be inhibitory.     

Contribution of planktonic and detritic fractions to the natural diet of mesozooplankton in Bahía Blanca Estuary

The pike, Esox lucius Linnaeus, is a predatory fish that supports important fisheries and could substantially impact prey populations around the temperate northern hemisphere. Consumption of prey by pike is most readily estimated using the energy budget to calculate food intake indirectly using estimates of growth rate and metabolism. Resting metabolic rate, R _s, is a particularly important component of such calculations. Here, the available estimates of R _s are reviewed and compared. Scaling coefficients for variation with body mass are consistent between the two studies in which they have been derived (0.81, 0.82). However, the effect of temperature on R _s markedly varies among studies (Q ₁₀ from 1.73 to 4.80). There is substantial variation in R _s (twofold to fourfold) among studies when temperature and fish size are accounted for. This variation is shown to have a large effect on energy budget calculations of energy intake and to be sufficient to account for imbalances in published budgets. These effects depend on age of pike and season; in one energy budget model, a 50% reduction in R _s resulted in decrease of 19–42% in estimated energy intake of pike. Potential causes of among-study variation in R _s are discussed and it is recommended that standard techniques by applied in the future to differentiate between genuine biological variation among populations and experimental factors. Guest editors: J. M. Farrell, C. Skov, M. Mingelbier, T. Margenau & J. E. Cooper International Pike Symposium: Merging Knowledge of Ecology, Biology, and Management for a Circumpolar Species     

Isolation of protoplasts and ion channel recording of plasma membrane patches and whole-cell recordings of the marine alga, <Emphasis Type="Italic">Ulva pertusa</Emphasis> (Chlorophyta)

Whole-cell patch-clamp techniques were used to study ion channels of a marine alga. High quality protoplasts suitable for electrophysiological studies were isolated from the green marine alga, Ulva pertusa, using enzyme mixtures consisting of cellulase and abalone power and identified by calcofluor fluorescence. The vitality of protoplasts varied depending on the alga growth stage, and those isolated from younger tissue in March maintained a high vitality with high sealing success rate compared with protoplasts isolated from mature or non-growing plants in August or November. In the whole-cell configuration, large inward currents were elicited by negative voltage pulses. The voltage-dependent component was predominantly carried by Cl⁻, as confirmed by the use of the Cl⁻ channel inhibitor DIDS and reversal potential of current-voltage plots. This evidence suggests that hyperpolarization-activated Cl⁻ permeable channels are responsible for the influx of Cl⁻ into U. pertusa cells. Voltage-dependent outward currents were also recorded in several protoplasts, and their properties need further investigation.     

Diversity of Bacterial Isolates from Commercial and Homemade Composts

The diversity of heterotrophic bacterial isolates of three commercial and two homemade composts was studied. The commercial composts were produced from poultry litter (PC), sewage sludge (SC), municipal solid waste (MC), and homemade composts (thermal compost [DC] and vermicompost [VC]) from food wastes. The taxonomic and physiological diversity of the heterotrophic culturable bacteria was assessed using phenotypic and genotypic characterization and the analysis of the partial 16S rRNA gene sequence. Composts DC and SC presented the higher genotypic diversity, as could be inferred from the number of distinct genotypic patterns observed, 28 and 21, respectively. Gram-positive bacteria, mainly Firmicutes, were predominant in all the composts. Some organisms related with taxa rarely reported in composts, as Rhodanobacter spathiphylli, Moraxella osloensis, Lysobacter, Corynebacterium, Pigmentiphaga kullae, and new taxa were also isolated. The highest relative proportion of isolates able to degrade starch was found in compost SC (>70%), to degrade gelatine in compost DC (>70%), to degrade Tween 80 in compost PC (>90%), and to degrade poly-epsilon-caprolactones in compost DC (>80%). Compost MC presented the lowest relative proportions of isolates able to degrade starch (<25%), gelatine (<20%), and poly-epsilon-caprolactone (<40%). When compared with the others, the homemade composts presented higher relative proportions of Gram-positive isolates able to inhibit the target organisms Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, or Pseudomonas aeruginosa. In compost MC, none of the Gram-positive isolates was able to inhibit those targets.     

Influences of calcium deficiency and cerium on the conversion efficiency of light energy of spinach

Chloroplast absorbs light energy and transforms it into electron energy, and then converts it into active chemical energy and stable chemical energy. In the present paper, we investigated the effects of Ce(3+), which has the most significant catalytic effects and similar characteristics with Ca(2+), on light energy conversion of spinach chloroplasts under Ca(2+)-deficient stress. The results illuminated that the Hill reaction activity, electron flow both photosystems and photophosphorylation rate of spinach chloroplasts reduced significantly under Ca(2+)-deficient condition, and activities of Mg(2+)-ATPase and Ca(2+)-ATPase on the thylakoid membrane were severely inhibited. Meanwhile, the activity of Rubisco, which is the key enzyme of photosynthetic carbon assimilation, was also prohibited. However, Ce(3+) decreased the inhibition of calcium deprivation the electron transport rate, the oxygen evolution rate, the cyclic and noncyclic photophosphorylation, the activities of Mg(2+)-ATPase, Ca(2+)-ATPase and Rubisco of spinach chloroplasts. All above implied that Ca(2+)-depletion could disturb light energy conversion of chloroplasts strongly, which could be reversed by Ce(3+).