Larval Rearing of Common Carp Cyprinus carpio: A Comparision Between Natural and Artificial Diets Under Three Stocking Densities

Common carp Cyprinus carpio larvae were cultured under two feeding conditions: live food or an artificial diet for 40 d in recirculating systems. Three stocking densities of 25 (low), 50 (medium), and 100 (high) larvae/15-L aquarium were maintained for each feeding treatment. Significantly higher survival (91%) and growth (401.08 ± 2.61 mg) were observed in the low density, live food system. Average weight of larvae in the live food system was 3- to 5-fold higher than larvae at the same stocking density for the artificial diet. Proteolytic activity showed a direct relationship with the length of the digestive tract (r = 0.95). The highest enzyme activity was observed in the low density, live food system. Survival and growth of common carp larvae are influenced by both the stocking density and the type of food.     

Epidemiological and morphological studies of double-chambered right ventricle in dogs

The double-chambered right ventricle (DCRV) is a rare congenital cardiac disease in dogs, and its detailed epidemiological and morphological features are not clearly understood. By investigating the profile, clinical signs, and characteristics of examination findings of eleven dogs with DCRV by means of a retrospective study, we attempted to clarify the epidemiology and morphology of the condition. The study group consisted of nine males and two females. Breeds included Pug (n=3), Miniature Dachshund (n=1), French Bull-dog (n=1), Shiba (n=1), and Retrievers (n=5). The attachment site of the anomalous muscular bundle was continuous with the cardiac apex in nine dogs, and it was attached to the right ventricle free wall in the other two dogs. In dogs with DCRV, at least one of the following conditions was present concurrently: congenital or acquired tricuspid valve regurgitation (TR), ventricular septal defect, and atrial septal defect. Also, the pressure difference between the two chambers increased over time, and progressive right-sided heart failure was observed. In summary, DCRV occurs in small breeds of dog as well as in large breeds of dog and it may be more prevalent in males. The existence of two types of DCRV in dogs was established. Dog with DCRVs will have a high incidence of concurrent cardiac abnormalities. Concurrent TR may be either congenital or acquired. DCRV is a congenital disorder, but the clinical condition progresses as the dog develops.     

Nucleotide sequence of the "denaturable" leucine transfer RNA from yeast

The nucleotide sequence of " denaturable"leucine acceptor transfer RNA (tRNA(Leu)(3)) from baker's yeast was determined on (32)P-labeled material. The molecule is 85 nucleotides long and can be folded into the "cloverleaf" model for secondary structure. The basis on which the sequence was deduced from the products of complete enzymatic digestion, prior to its unambiguous determination, is presented.     

Synthetic biology: regulating industry uses of new biotechnologies

In our view, synthetic biology is an extension of the continuum of genetic science that has been used safely for more than 40 years by the biotechnology industry in the development of commercial products. Examples of synthetic biology use by biotechnology companies illustrate the potential to substantially reduce research and development time and to increase speed to market. Improvements in the speed and cost of DNA synthesis are enabling scientists to design modified bacterial chromosomes that can be used in the production of renewable chemicals, biofuels, bioproducts, renewable specialty chemicals, pharmaceutical intermediates, fine chemicals, food ingredients, and health care products. Regulatory options should support innovation and commercial development of new products while protecting the public from potential harms.     

Nitrate reduction and denitrification in flooded soils

It has been well known that the utilization rate of ammonium sulfate fertilizer by lowland rice was as low as 40 percent of the applied ammonium. This low utilization rate was due to nitrogen loss from the paddy field. There are problems as to whether the loss of nitrogen from the flooded soil was caused by the nitrification of ammonium nitrogen and its subsequent denitrification, by the evaporation of ammonium, or by the leaching of ammonium-nitrogen with percolated water. Shioiri and his associatesll clarified that this loss of nitrogen resulted largely from denitrification through nitrate reduction in 1942. After the paddy soil is flooded with water, the oxygen in furrow slice is consumed by aerobic microorganisms, and then the soil becomes reductive. Conversely the oxigen is supplied to the soil through the water from the air, and from various kinds of algae and duckweeds, which produce oxygen through photosynthesis. At the early stage the reduction by oxygen consumption is superior to the oxidation by oxygen supply, the furrow slice is reductive, and is bluish gray in color due to the presence of certain ferrous compounds. After months flooding, the oxygen supply becomes superior to oxygen consumption and the uppermost layer of furrow slice becomes brown in color due to the presence of ferric compounds. This layer corresponds to an “oxidised layer” where microorganisms live aerobically. In this oxidized layer the nitrifying bacteria converts ammonium nitrogen into nitrate nitrogen which is percolated into the reduced layer, and lost through denitrification. A large amount of ammonium sulfate fertilizer is then dressed at the uppermost layer, after flooding, the loss of nitrogen through denitrification is serious.     

Diversity of S-RNase genes and S-haplotypes in Japanese plum (Prunus salicina Lindl.)

Summary

This report demonstrates the diversity of S-haplotypes in Japanese plum by molecular cloning of genomic DNAs and cDNAs that encode S-RNases. Nine different DNA fragments, designated as S^a–Sⁱ, were obtained from 17 Japanese plum cultivars by PCR with an S-RNase gene-specific primer set, Pru-C2 and PCE-R. Eleven different S-haplotypes were found in these cultivars. The banding patterns obtained with another S-RNase gene-specific primer set, Pru-T2 and PCE-R, corresponded to the S-haplotypes predicted from the Pru-C2 and PCE-R primer set. Several cultivars had the same S-haplotypes. Partial genomic DNAs for eight S-RNase genes and cDNAs for two S-RNases were cloned and sequenced. Deduced amino acid sequences contained conserved regions among the rosaceous S-RNases. Comparisons of the sequences from cDNAs and genomic DNAs revealed the presence of two introns in the S-RNase genes of Japanese plum as in other Prunus S-RNase genes. Pollination incompatibility groups and self-compatibility in Japanese plum were discussed with reference to the S-haplotypes.     

Determining the S-genotypes of several sweet cherry cultivars based on PCR-RFLP analysis

Summary

Based on the cDNA sequences encoding sweet cherry self-incompatibility associated ribonucleases (S-RNases), a PCR-based S-allele typing system for sweet cherry cultivars has been recently developed. Using this technique, we determined S-genotypes of the three newly released Japanese cvs Kouka-Nishiki, Beni-Sayaka and Beni-Shuho and one British cv Merton Glory that was classified as a Universal Donor, which is able to be used as a pollen donor for all cultivars in pollen incompatibility groups I to XIII. Furthermore, we also determined the partial sequences of the S-RNase genes of ‘Rainier’ (S¹S⁴)‘ and ‘Sato-Nishiki (S³S⁶)’,which leads to the development of a more reliable S-allele identification method of PCR-RFLP for sweet cherry cultivars. Total DNA isolated from leaves of the four cultivars along with those from ten cultivars with known S-genotypes were PCR amplified with two sets of primers that were designed from DNA sequences encoding the signal peptide (Pru-T2) and two conserved domains (Pru-C2 and Pru-C4R) of sweet cherry S-RNases. By comparing the size of PCR products on agarose gel, the 5-genotypes of ‘Kouka-Nishiki’, ‘Beni-Sayaka’, ‘Beni-Shuho’ and ‘Merton Glory’ were suggested to be S¹S³, S¹S⁶, S⁴S⁶, and S⁴S⁶, respectively. Two of these three S-genotypes (S¹S⁶ and S⁴S⁶) were found for the first time. DNA sequencing of PCR products from S-alleles of ‘Rainier’ and ‘Sato-Nishiki’ revealed that Ban II, Nru I, Apa LI and Ava I sites, respectively, were unique in the S¹-, S³-, S⁴- and S⁶- sequences flanked by Pru-T2 and Pru-C4R primers. RFLP analysis of the PCR products using these enzymes confirmed that S¹-, S³-, S⁴- and S⁶-alleles of the four cultivars contained the respective restriction enzyme recognition sites.     

The Delignification Pattern of Ailanthus excelsa Wood by Inonotus hispidus (Bull.: Fr.) P. Karst.

In vitro laboratory decay tests on Ailanthus excelsa Roxb. wood revealed that I. hispidus exhibits a combination of both white-rot and soft-rot patterns of wood decay. Early stages of wood decay showed dissolution of the middle lamella as well as defibration and localized delignification of fiber walls; vessels, axial, and ray parenchyma remained unaltered. Delignification commenced from the middle lamellae at the cell corners without any marked effect on the primary and secondary wall layers. In later stages of growth, the species produces typical soft-rot decay pattern by forming erosion channels through the S₂ layers of fiber walls, transverse bore holes in the cell walls, and erosion channels alongside/following the orientation of cellulose microfibrils. The rays showed signs of cell wall alterations only after the extensive damage to the fiber walls. After 120 days of incubation, the vessels also showed localized delignification, the erosion of pits, and separation from associated xylem elements. The extensive weight losses under natural and in vitro decayed wood as well as the very soft nature of severely degraded wood indicate that I. hispidus alters wood strength and stiffness.