Modeling the effects of climatic and co2 changes on grassland storage of soil C

We present results from analyses of the sensitivity of global grassland ecosystems to modified climate and atmospheric CO₂ levels. We assess 31 grassland sites from around the world under two different General Circulation Models (GCM) double CO₂ climates. These grasslands are representative of mostly naturally occurring ecosystems, however, in many regions of the world, grasslands have been greatly modified by recent land use changes. In this paper we focus on the ecosystem dynamics of natural grasslands. The climate change results indicate that simulated soil C losses occur in all but one grassland ecoregion, ranging from 0 to 14% of current soil C levels for the surface 20 cm. The Eurasian grasslands lost the greatest amount of soil C (～1200 g C m^?2) and the other temperate grasslands losses ranged from 0 to 1000 g C m^?2, averaging approximately 350 g C m^?2. The tropical grasslands and savannas lost the least amount of soil C per unit area ranging from no change to 300 g C m^?2 losses, averaging approximately 70 g C m^?2. Plant production varies according to modifications in rainfall under the altered climate and to altered nitrogen mineralization rates. The two GCM's differed in predictions of rainfall with a doubling of CO₂, and these differences are reflected in plant production. Soil decomposition rates responded most predictably to changes in temperature. Direct CO₂ enhancement effects on decomposition and plant production tended to reduce the net impact of climate alterations alone.     

Suitability of Japanese codling as a raw material for surimi-based products revealed by primary sequence analysis of myosin heavy chain and thermal gel properties

Fisheries Science - Complementary DNA encoding a part of myosin heavy chain was cloned from fast skeletal muscle of Japanese codling Physiculus japonicus. Japanese codling, a frequent catch off the...     

Daily change of genetic variability in hatchery offspring of red sea bream during spawning season

ABSTRACT:   In order to assess a daily change of genetic variability during spawning season, hatched larvae of red sea bream sampled on different dates were assayed by polymorphic markers such as microsatellite DNA (msDNA) and mitochondria DNA (mtDNA) control region. Based on the microsatellite loci, the average number of alleles per locus ranged between 13.7 and 18.3. The expected heterozygosities ranged between 0.843 and 0.919. A total of 23 mtDNA haplotypes were detected via digestion of mtDNA D-loop sequences with five endonucleases: Taq  I, Alu  I, Mbo  I, Rsa  I and Hinf  I. Significant fluctuation of genetic variability during spawning season was detected by both types of DNA markers. It was suggested that the genetic variability was maintained by pooling the seed fish collected on different spawning dates in a hatchery.     

Isolation and characterization of microsatellite DNA markers in endangered Mekong giant catfish Pangasianodon gigas

ABSTRACT:   The Mekong giant catfish is one of the largest freshwater fish in the world, and is endemic to the Mekong basin. Recently, the number of Mekong giant catfish has drastically decreased. In this study, seven microsatellite DNA markers of the Mekong giant catfish were developed for evaluation of the species' genetic diversity. Mendelian inheritance of four of seven markers was confirmed using offspring (F1) produced from one pair. Number of alleles per locus in the founder population ranged 1–4 with a mean of 2.8, and that in F1 ranged 1–2 with a mean of 1.6. The expected heterozygosity in the founder population ranged 0–0.66 with a mean of 0.38, and that in F1 ranged 0–0.5 with a mean of 0.28. The mean expected heterozygosity in the founder population is apparently lower than that in Pangasius bocourti and other freshwater species, but higher than that in endangered species. In the future, the microsatellite data in this study will be used in minimal kinship approaches, because these individuals constitute the basic seed for release into wild in an effort to conserve the native population of Mekong giant catfish.     

Purification and biochemical characterization of a cellulase from the digestive organs of the short-spined sea urchin Strongylocentrotus intermedius

We isolated a cellulase from the digestive organs of the short-spined sea urchin Strogylocentrotus intermedius using a combination of ion-exchange chromatography and gel filtration together with an assay for carboxymethylcellulase activity. The isolated cellulase was stained as a single band by Congo red. The molecular weight of the isolated cellulase, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, was 59?kDa. The isolated cellulase exhibited hydrolytic activity toward carboxymethyl cellulose, with an optimum temperature and pH of 30?°C and pH 8.0, respectively. The thermal stability of the enzyme was characterized by determining the temperature at which activity decreased by 50?% with treatment for 30?min at pH 7.0 and found to be 32?°C. Cellulase activity remained at a high level at 5?C20?°C, which is the growth temperature of the short-spined sea urchin. These results confirm that the short-spined sea urchin should preferably be reared at a water temperature of <20?°C.     

Genetic and environmental variances on growth and reproductive traits of silver crucian carp Carassius langsdorfii using communal and separate rearing systems

SUMMARY: Five clonal lines of silver crucian carp Carassius langsdorfii were produced from natural maternal fish to estimate the variance and heritability of total length, bodyweight and gonadosomatic index (GSI). The larvae on the 10th day after hatching were reared together in a common rearing system with five duplicate systems. Another system was prepared using a separate system with two replications in each family. Estimation of variance and heritability were done in the first, third, fifth and 10th month for total length and bodyweight. Microsatellite DNA markers were used to identify the clonal lines in each communal rearing tank. Average heritabilities in the first month were 0.105 for total length (ranging from 0.21 to 0.03) and 0.127 for bodyweight (ranging from 0.22 to 0.06) then decreased in the third, fifth and 10th month. In contrast, intermediate levels of heritability from separate systems were observed. Likewise, relative heritability of GSI in the 10th month presented a high level in both rearing systems. Those heritabilities indicated that growth, total length, bodyweight and reproductive performances of silver crucian carp were affected by genetic influence. The results suggest that clonal lines of silver crucian carp are suitable as experimental animals for evaluations of environmental change and various pollutants through quantitative traits such as growth, reproductive and other physiological traits.     

Genetic evaluation of interindividual relatedness for broodstock management of the rare species barfin flounder Verasper moseri using microsatellite DNA markers

ABSTRACT:   The barfin flounder has been recently declared to be rare, as the number of wild individuals in Japan has greatly reduced since 1975. The Japanese National Center for Stock Enhancement started the stocking program for this species on 1987. In the present study, microsatellite DNA loci were applied in order to determine the pedigree of the hatchery-produced juveniles for stock enhancement. Additionally, using six polymorphic microsatellite markers, the accuracy to assign dyads to categories of kinship was estimated using the relatedness estimator ( R _XY), similarity indexes (individual genetic identity [GI] and proportion of shared alleles [ P _S]), identification of kin groups using unweighted pair group method with arithmetic mean (UPGMA) clustering based on interindividual genetic distances (1- R _XY, 1- P _S, and 1-GI), a likelihood ratio approach, and partition methods to separate individuals into cohorts. The results were compared with the pedigree relationship previously obtained from parentage analysis. Estimation of the kinship relationship between individuals could be better inferred by means of UPGMA dendrogram clustering based on 1-GI or 1- P _S as interindividual genetic distances, or using computer software to perform partitioning of set of individuals.     

Differentiation of epithelial cells to M cells in response to bacterial colonization on the follicle-associated epithelium of Peyer's patch in rat small intestine

To clarify the relationship between M cells and intestinal microflora, histoplanimetrical investigation into the bacterial colonization and the differentiation to M cells was carried out in rat Peyer's patch under physiological conditions. The follicle-associated epithelium (FAE), except for the narrow area of apical region, was closely covered with both neighboring intestinal villi and a thick mucous layer, the latter of which also filled the intervillous spaces as well as the space between the FAE and the neighboring intestinal villi. Indigenous bacteria adhered almost constantly to the narrow areas of apical regions of both intestinal villi and the FAE. Bacterial colonies were occasionally located on the basal to middle region of FAE, where M cells also appeared, forming large pockets. When bacterial colonies were located on the basal to middle region of FAE, bacteria with the same morphological characteristics also proliferated in the intervillous spaces neighboring the Peyer's patch. In cases with no bacterial colonies on the basal to middle region of FAE, however, M cells were rare in the FAE. Histoplanimetrical analysis showed the similar distribution pattern of bacterial colonies on the FAE and M cells in the FAE. M cells ultrastructurally engulfed indigenous bacteria, which were then transported to the pockets. These results suggest that indigenous bacterial colonization on the FAE stimulates the differentiation of M cells in the FAE under physiological conditions. The uptake of bacteria by M cells might contribute the regulation of the development of indigenous bacterial colonies in the small intestine.