Census and effective population sizes of white‐spotted charr (Salvelinus leucomaenis) in a fragmented landscape

Several habitat models have been proposed to predict population size for stream fishes and to guide habitat assessment and monitoring techniques. However, most models do not incorporate the potential advantage of molecular genetic markers. We conducted a field survey and microsatellite DNA analyses to quantify the relationships among genetic diversity, census/effective population size and habitat variables in fragmented populations of white‐spotted charr (Salvelinus leucomaenis). The census population size significantly increased with the stream length, the number of pools and a pool‐riffle sequence index, a proxy for channel‐unit habitat type complexity within reaches. Population density was correlated with the pool‐riffle sequence index only. Genetic diversity and effective population size were not correlated with the habitat variables or census population size. There was a lack of isolation‐by‐distance population structure in the studied populations. Our results suggest that stream length and the number of pools within reaches associated with habitat complexity are the habitat variables that explain the majority of variation in population size of white‐spotted charr. Our findings provide further evidence that census population size per se is a poor indicator of the inclusive genetic diversity within populations in a fragmented landscape.     

Cytogenetic identification of a hybrid owl monkey, Aotus nancymaae x Aotus lemurinus griseimembra.

A neonate male owl monkey (Aotus sp.) was identified cytogenetically as a hybrid after it failed to nurse and died. Phenotypically, the male parent possessed characteristics of the "gray-neck group," and G-banded karyotypes identified him as Aotus lemurinus griseimembra (2n = 53), heterozygous for the centric fusion of chromosomes 13 and 14. The female parent belonged to the "red-neck group" and was identified cytogenetically as Aotus nancymaae (2n = 54). The neonate hybrid had 2n = 54 chromosomes with 13 homologous pairs of autosomes, 26 nonhomologous autosomes, and XY sex chromosomes. Thirteen of the nonhomologous chromosomes represented the paternal complement, and 13 were from the maternal complement. Chromosomal rearrangements occurring between the karyotypes of A. l. griseimembra and A. nancymaae were believed to include two paracentric inversions, a reciprocal translocation, and two complex rearrangements involving pericentric inversion, telocentromeric fusion, and centromeric adjustment. Cytogenetic analyses are necessary to identify most Aotus taxa and thus should be utilized to pair chromosomally compatible animals and avoid interspecies hybridization.     

The effect of strain, growth stage, and cultivating condition of Ganoderma lucidum on 5α-reductase inhibition

The inhibitory effects of 102 methanol extracts of 40 mycelia, 9 culture fluids, and 53 fruiting bodies of 40 strains of Ganoderma lucidum on 5-reductase were investigated. The methanol extract of the fruiting body of each strain was found to show the strongest 5-reductase inhibitory activity among the extracts tested.     

Genetic identification of native populations of fluvial white-spotted charr <Emphasis Type="Italic">Salvelinus leucomaenis</Emphasis> in the upper Tone River drainage

ABSTRACT:   Stocking of exogenous, hatchery-reared white-spotted charr Salvelinus leucomaenis has been conducted throughout much of their range in Honshu Island, Japan, to increase angling opportunities. Although the native charr populations are thought to have declined because of hybridization with introduced fish, their distribution and genetic status have been uncertain. Fine population structures of charr in the upper Tone River drainage were examined using mitochondrial DNA and microsatellite analyses so as to clarify the presence of native populations. One common mtDNA haplotype was detected in all populations in the Ohashi River and Watarase River, and four and one tributary populations were monomorphic for such haplotypes, respectively. However, several haplotypes, considered to have originated from stocked hatchery fish, were observed in the stocked and the remaining populations. Judging from the genetic integrity over a fine geographic scale, the former were considered as indicative of native populations and the latter as admixtures with hatchery fish. Comparisons of genetic diversity, deviations from the Hardy–Weinberg equilibrium, principal component analysis, and relatedness estimations based on microsatellite DNA can also provide evidence for distinguishing native populations from those influenced by hatchery fish.     

Infection and colonization of aseptically micropropagated sugarcane seedlings by nitrogen-fixing endophytic bacterium, Herbaspirillum sp. B501gfp1

In this study, we used Herbaspirillum sp. B501gfp1 (B501gfp1), an isolate from wild rice, to investigate the interaction between a non-host nitrogen-fixing endophytic bacterium and micropropagated sugarcane plants under aseptic condition. Two Japanese sugarcane plants (Saccharum sp.) cultivars (cvs) NiF8 and Ni15 were inoculated using B501gfp1 in two inoculum doses of 10⁸ and 10² bacterial-cells-per-milliliter suspension. The results showed that bacterial cells colonized both the root and stem tissues, and colonization was apparent in the intercellular spaces. Higher bacterial numbers were detected in plant tissues inoculated with the higher inoculum concentration treatment. Bacterial numbers also varied between the two cultivars, with the higher values determined in cv Ni15. This study provides evidence that Herbaspirillum sp. B501gfp1, a rice isolate, could colonize sugarcane tissues, suggesting non-specificity of host plant among endophytes.     

Production of growth-promoting substances and high colonization ability of rhizobacteria enhance the nitrogen fixation of soybean when coinoculated with Bradyrhizobium japonicum

Understanding the interaction mechanisms between plant growth-promoting rhizobacteria (PGPR), leguminous crops, and rhizobia is necessary to effectively use PGPR in increasing the biological nitrogen fixation of legumes. We determined the coinoculation effects of Bradyrhizobium japonicum A1017 and a gusA-marked strain of Pseudomonas fluorescens 2137, P. fluorescens WCS365, Azomonas agilis 125, and Azospirillum lipoferum 137 on soybean [Glycine max (L.) Merr] cv. Enrei grown under axenic conditions. The gusA-marked rhizobacteria effectively colonized the root tips and surfaces near the roots tips with a colonization rate ranging from 7.50 to 8.62 log colony forming units (cfu) gfw^-1. P. fluorescens 2137 had the highest colonization activity on soybean roots whether inoculated alone or coinoculated with B. japonicum A1017. Coinoculation of P. fluorescens 2137 and B. japonicum A1017 increased the colonization of B. japonicum A1017 on soybean roots, nodule number, and acetylene reduction activity (ARA) at 10 and 20 days after inoculation. Moreover, the addition of sterile spent medium of P. fluorescens 2137 increased the growth of B. japonicum A1017 in yeast mannitol broth (YMB), indicating that P. fluorescens 2137 may have released substances that increased the rhizobial population. The results of this study suggest that the enhanced nodulation and ARA of soybean due to the high colonization of P. fluorescens on soybean roots could depend on the production of growth-promoting substances that stimulate the growth of B. japonicum. However, coinoculation with P. fluorescens WCS365 decreased the nodule number and ARA, despite its slight stimulation of the growth of B. japonicum on the roots, indicating that coinoculation effects are strain dependent.     

Adsorption behavior of heavy metals on biomaterials

We have investigated adsorption of Cd(II) and Pb(II) at pH 2-6.7 onto the biomaterials chitosan, coffee, green tea, tea, yuzu, aloe, and Japanese coarse tea, and onto the inorganic adsorbents, activated carbon and zeolite. High adsorptive capabilities were observed for all of the biomaterials at pH 4 and 6.7. In the adsorption of Cd(II), blend coffee, tea, green tea, and coarse tea have comparable loading capacities to activated carbon and zeolite. Although activated carbon, zeolite, and chitosan are utilized in a variety of fields such as wastewater treatment, chemical and metallurgical engineering, and analytical chemistry, these adsorbents are costly. On the other hand, processing of the test biomaterials was inexpensive, and all the biomaterials except for chitosan were able to adsorb large amounts of Pb(II) and Cd(II) ions after a convenient pretreatment of washing with water followed by drying. The high adsorption capability of the biomaterials prepared from plant materials is promising in the development of a novel, low-cost adsorbent. From these results, it is concluded that heavy metal removal using biomaterials would be an effective method for the economic treatment of wastewater. The proposed adsorption method was applied to the determination of amounts of Cd(II) and Pb(II) in water samples.     

Xenografting of bovine secondary follicles into ovariectomized female severe combined immunodeficient mice

Xenografting of ovarian tissue into immunodeficient mice has been used as a model to study the dynamics of follicular development and provides an alternative method for the production of mature oocytes. In a previous experiment, we demonstrated that xenografted bovine secondary follicles developed to the antral stage in severe combined immunodeficient (SCID) mice. In the present study, we examined the development of bovine secondary follicles (140-190 microm in diameter) grafted into ovariectomized mice in comparison with intact female mice as a control. At 4 weeks after grafting, several antral follicles ranging from 350 to 550 microm (457.6 +/- 50.8 microm) in diameter were found in the control mice, while a single large (larger than 2.5 mm) antral follicle and other small follicles were observed in every ovariectomized mouse. At 6 weeks after grafting, the mean diameter of morphologically normal follicles had further increased in the control group (591.8 +/- 132.0 microm). In ovariectomized mice, however, the mean diameter of follicles decreased (4 weeks: 864.2 +/- 988.2 microm; 6 weeks: 496.5 +/- 137.6 microm), since the single large antral follicle observed at 4 weeks had degenerated by 6 weeks. In control mice, more than 70% of follicles were morphologically normal and formed an antrum, and most of the follicles contained morphologically normal oocytes which grew to 122.5 +/- 2.2 microm. In ovariectomized mice, morphologically normal oocytes also grew larger than before grafting, but their survival rate was significantly lower than that in control mice. These results suggest that ovariectomy of host mice alters the developmental pattern of xenografted bovine secondary follicles to accelerate a single follicle to develop in the graft.     

Potassium behavior and clay mineral composition in the soil with low effectiveness of potassium application

ABSTRACT

Increasing exchangeable potassium (ExK) content in soil to an appropriate level is important to mitigate the transfer of radioactive cesium to crops. We focused on a buckwheat (Fagopyrum esculentum Moench) field with a low ExK content, despite the application of K, in Fukushima Prefecture, Japan (Field A), following the Tokyo Electric Power Company Fukushima Dai-ichi (No. 1) Nuclear Power Plant accident in March 2011. We examined the relationship between K concentration and clay mineral composition in the soil of Field A and compared the findings with another field in Fukushima Prefecture (Field B) to clarify whether K applied to the soil was leached or remaining fixed. Pot experiments showed that K concentration in water seepage from pots following irrigation was significantly lower in pots from Field A than in those from Field B. Soil ExK content after soybean cultivation was lower in soils of Field A than those of Field B. These results indicate that K applied to Field A was fixed in the soil. Analysis of clay mineral composition confirmed the distinctive vermiculitic nature of Field A soils. This clay mineralogy would be associated with the higher K fixation ability of Field A than Field B soils. This study demonstrated that K fixation in vermiculite was a factor preventing the increase in ExK content from K application to Field A.     

Shoot control of nodulation is modified by the root in the supernodulating soybean mutant En6500 and its wild-type parent cultivar Enrei

Abstract

Based on grafting studies, both supernodulating (Carroll et al. 1985a, b) and hypernodulating (Gremaud and Harper 1989) soybean ([itGlycine max} L. Merr.) phenotypes were reported to be under the control of shoot factors (Delves et al. 1986, 1987; Cho and Harper 1991). Recently Akao and Kouchi (1992) have isolated a new supernodulating mutant (En6500) from ethyl methane sulfonate (EMS)-treated Enrei, a cultivar which is widely grown in the central districts of Japan. This mutant has been shown to produce several fold as many nodules as its wild-type parent cultivar when grown at a low concentration (0.5 mol m^-3) of nitrate. Moreover, it exhibited a continuous increase in the nodule number with the increasing nitrate concentration, even at 15 mol m^-3 (Francisco et al. 1992), in contrast to the similar mutant nts382 in which the nodulation decreased even at the relatively low nitrate level of 5.5 mol m^-3 (Carroll et al. 1985a). In this study we conducted grafting experiments to determine which plant part controls the supernodulation of En6500.