Transfer and expression of mutations in pleiotropic genes determining the synthesis of extracellular enzymes in Bacillus subtilis

The mutations in the genes determining the levels of extracellular enzymes production were transferred into Bacillus subtilis 168 strain by genetic transformation technique. The method used has permitted registering the transfer of pleiotropic genes. Seven amylase producers were detected among 126 his+ transformants screened, as well as five metalprotease producers among 246 gly+ transformants. Cotransfer of pap and hpr mutant genes linked with his+ or gly+ genes might result in finding the producers among the mentioned prototrophic transformants. Selection of linked markers in transformation, presented in the paper, is discussed to be a useful technique for obtaining producer strains for industrial production.     

Specificity of antibodies established from mammals in rainbow trout (Oncorhynchus mykiss)

This study deals with the question as to whether antibodies established for mammals are also specific for rainbow trout. The reason for this examination is the major economic importance of rainbow trout in aquaculture and the growing scientific attention. However, there are few primary antibodies so far defined for this fish species. Therefore, the aim of the current study was to test the ability of 15 commercially available antibodies for rainbow trout in an indirect immunofluoresence assay to analyse tissue sections of organs. Five commercially available primary antibodies were identified, which were directed against proteins of one or two organs/ cell types in rainbow trout.     

Immobilization of yeast ADH by adsorption onto polyaminomethylstyrene

Summary Yeast alcohol dehydrogenase (EC 1.1.1.1) (Y-ADH) was immobilized by adsorption onto polyaminomethylstyrene (PAMS). The adsorption was rapid and yielded a product, the operational and storage stability of which depended on the initial content of enzyme and to a great extent on the composition of the adsorption buffer. The best results were obtained in the presence of 0.05 M phosphate solution, pH 8.8, containing 2 M sodium chloride. The amount of adsorbed ADH correlates with the position of anions in the Hofmeister series. After 1,000 bed volumes of the standard assay mixture have flowed through the column, there is no decrease in activity. It is possible to prepare adsorbates using crude yeast extracts as enzyme source. The stability of the immobilized enzyme is similar to that obtained with crystalline ADH preparations.     

Purification and various properties of NADP+-dependent alcohol dehydrogenase from Acinetobacter calcoaceticus]

The constitutive NADP+-dependent alcohol dehydrogenase from Acinetobacter calcoaceticus can be accumulated about 50 fold in 3 purification steps. The end-product shows in the analytical polyacrylamide gel electrophoresis only one active enzyme band. The molecular weight of the enzyme was determined to be 235,000 by gel chromatography on Sephadex G 200, the smallest subunit shows a molecular weight of 61 000 on SDS electrophoresis. The isoelectric point is at 5.84. The KM values determined with primary aliphatic alcohols diminish in the range of the homologous order (C2--C10) with growing chain length. The KM value for hexanal is about 20 fold less than that for 1-hexanol.     

Integrated production and distribution planning for perishable food products

Certain types of food, such as catering foods, decay very rapidly. This paper investigates how the quality of such foods can be improved by shortening the time interval between production and delivery. To this end, we develop an approach that integrates short-term production and distribution planning in an iterative scheme. Further, an aggregation scheme is developed as the interface between the production scheduling and distribution problem. The production scheduling problem is solved through an MILP modeling approach which is based on a block planning formulation. Our implementation shows promising results, elaborated in a numerical investigation, which recollects the real settings of a catering company located in Denmark.     

Observations of growth changes during the embryonic-larval-transition of pikeperch (Sander lucioperca) under near-natural conditions

Sander lucioperca is an organism of growing importance for the aquaculture industry. Nonetheless, the rearing of S. lucioperca larvae is proving to be a difficult task as it is facing a high mortality rate during hatching and the change to exogenous feeding. To gain insight into growth patterns during this period, the authors analysed pikeperch embryos and larvae from 9 days before hatching to 17 days after hatch. Hereby they were able to describe a natural development by using close to natural conditions based on using a direct flow-through supply of lake fresh water on specimens from a local wild population. The results show that between the early embryonic stages a steady growth was visible. Nonetheless, in between hatching and the start of exogenous feeding, a phase of growth stagnation took place. In the following larval stages, an increased growth with large size variations between individual specimens appeared. Both factors are conspicuous as they can indicate a starting point for cannibalism. With this analysis, the authors can provide a fundament to support the upcoming research on S. lucioperca and aid to optimize size-sorting procedures for a higher survival of pikeperch stock in aquaculture.