First transgenic cereal plants have been obtained in Poland seven years ago. Within the time other cereals like wheat, rye and barley have been also transformed. The prerequisite for that was a very efficient regeneration system by somatic embryogenesis. Generally the basic study on transgenic cereals are quite advanced but the question is how to include transgenic lines in to practical breeding process? Most of genes, promoters and transformation methods are patented and probably Polish breeders will never afford to buy the licences. Though there is a need to concentrate the future work in Polish institutes on identification and isolation of genes of interest. Than to transfer them to plants and register transgenic varieties. According to the Polish law it is allowed to carry out the field experiments, but it is not possible to register the plant variety.
Biodegradation was carried out in the laboratory continous-flow activated sludge system and the river water test.In the river water tests, the source of carbon and energy for the microorganisms was nonionic surfactant or nonionic surfactant and glucose.The river ware tests were conducted with and without plants as Cryptocoryne.it has been found that the nonionic surfactant with chain branching was readily biodegradable in the cooxidation process by the microorganisms of activated sludge and microorganisms from the river water test.
The sweet cherry rootstocks Gisela 5, Weiroot 10, Damil, Edabriz, Maxma, PHL 84 were propagated and rooted by tissue culture. The micropropagation was carried out on MS medium (Murashige and Skoog, 7) with modification. Medium A ? full strength MS with addition of 0,5 mg/l BA and 0,1 mg/l IBA, medium B ?half strength of MS nitro-elements with addition of 2,0 mg/l BA and 0,1 mg/l IBA. Two-steps rooting was carried out on WPM medium (Lloyd and McCown, 8), induction of roots on WPM medium with addition of 2,0 mg/l IBA and 5,0 mg/l IAA, after 9-10 days shoots were transferred onto WPM medium without hormones. The highest multiplication coefficient was obtained for Weiroot 10. Gisela 5 was proved to be the most susceptible to vitrification. The best rooting was calculated for Gisela 5-94,7%, at mean length of root ? 3,2 cm.
This review presents chemical and biochemical properties of trehalose. Moreover, the results of studies on biosynthesis and accumulation, as well as some aspects of thermotolerantion and osmoadaptation are discussed. The existing and potential applications in many fields, which may be medical or biological, are listed therein.
The recombinant human prolactin was synthesised as an extracellular protein expressed in baculovirus system. The concentration of prolactin in TC-100 medium was approximately 40 mg/l when the conditions of recombinant virus infection were properly chosen. The human prolactin present in culture medium was stable at 4C for several months up to one year. The recombinant product was a survival factor for the insect cells. In the presence of prolactin in the medium, the cells did not show any signs of lysis or disruption, which is in agreement with the view of the antiapoptotic action of prolactin. The results of Western-blot analysis showed similar ratio of glycosylated/non-glycosylated forms of the recombinant product to the hormone forms present in human physiological (osmiotic) fluids. The recombinant protein was biologically active as determined in mammary gland explant system. The recombinant hormone present in the culture media was shown to induce mRNAs for two milk proteins ? beta-casein and WAP in mammary explants cultured in the presence of insulin and hydrocortisone. The effect of the hormone was dose-dependant and the largest accumulation of both mRNAs was observed at rec-hPRL concentration of 0.1 mug/ml (approx. 4.3 x 10 -9 M). In this respect, the activity of the recombinant human prolactin was equal or even higher than that of bovine pituitary prolactin or human growth hormone.
Organotins are ubiquitos in the environment. They are commonly used as a component of plant protective agents, antifouling paints, PVC stabilisers, catalyst and wood preservatives. Some organotins show deleterious effects on different organisms even at very low concentration. Of particular importance to the environment is high toxicity of tributyltin (TBT). Biotransformation of organotin compounds by dealkylation or methylation has been observed. This paper focused on the interactions of microorganisms with organotins including bioaccumulation, detoxification and degradation.
Absidia orchidis can be used as a source of several enzymes, amongst which chitosanase is one of the most interesting. Chitosanase hydrolyses the links between the mers of glucosamine or between mers of glucosamine and N-acetylglucosamine in the chains of chitosan and chitin. The aim of the presented work was the preliminary investigations of the chitosanase from the fungus Absidia orchidis. This chitosanase is an intracellular enzyme with molecular weight approx. 36 000 Da. The optimal conditions for a hydrolysis of chitosan were pH 4.5 and temperature 25C. This enzyme is stable at the optimal temperature for 24-48 hours, but after 7 days it was inactivated.
It is generally assumed that RNA recombination is one of the major driving forces in the evolution of plant viruses. This process leads to rearrangements of viral genomes and plays an important role in adaptation, genome repair and genetic variability of RNA viruses. It has been observed that viruses could recombine not only with each other, but also with mRNA of transgenic plants expressing viral genes. This observation has given rise to new concerns about creating virus-resistant transgenic plants, because the recombination could generate the viruses with new properties that were different from the parental strains. In this article, we present the current state of knowledge about recombination between transgens and challenging virus, we discuss what may happen in a field during interaction between the virus and the transgenic plant, and we propose strategies that allow to control the virus-transgene crossovers.
Chimera is a composite organism, consisting of cells derived from more than one embryo. The first experimental chimera was produced in 1961 and until today, chimeric animals have been widely used in mammalian experimental embryology. Numerous aggregation and injection techniques have been used to produce chimeras. Although most experimental chimeras were made of murine embryos, chimeric animals have been also produced in such species as: rat, hamster, deer mouse, rabbit, pig, sheep and in cattle. Some successful attempts to produce interspecific chimeras have been also made. Pigmentation is still widely used as a marker of chimerism, but new transgenic markers are now available. New methods emplying chimeric technique, like blastocyst complementation assay and lethal phenotypes rescue, provide new insights into developmental genetics. Nowadays, chimeric embryos are also likely to play a major role in the production of transgenic animals with the help of chimeric cloning technique.
Animals possess an inducible antibody immune system that acts as a defence against diseases.It is known that plants can also be active immunized against disease-causing pathogenes.This phenomenon is a result of the development of systemic acquired resistance (SAR).This article discussed recent studies on the role of salicilic acid (SA) in plants during the development of SAR.The understanding of the molecular and physiological background SAR may be applied in modern agrobiotechnology and pharmaceutical industry.
Genetic transformation of cereal crops is a powerful research tool for analysis of gene function and varietal improvement. Application of the method is possible when the expression of introduced transgene is on the desired level and stable over several generations. The production of transgenic cereals was mainly performed by microprojectile bombardment. However, some advance was also achieved by application of Agrobacterium-mediated transformation. For rice, which is the cereal model species, this method is routinely used, while for many others, especially polyploids, it has been developed very recently and only in a few laboratories. We still lack the knowledge whether the main features of Agro-mediated transformation (i.e. integration of one or few copies usually not rearranged and well defined transgene cassette) influence the transgene expression in polyploid cereal species. This review discusses known mechanisms possibly involved in transgene silencing, using both transformation methods. Part of the discussion is focused on transgene expression / silencing in relation to large genomes of polyploid cereals. Another application of genetic transformation, based on RNAi technology (RNA interference), is silencing of selected genes. This could be used to study gene function as well as to induce silencing of the native, single or family genes of cereals. Two strategies of silencing are discussed: a strategy of transcriptional gene silencing (TGS) and posttranscriptional gene silencing (PTGS).
During the past 15 years, the methylotrophic yeast Pichia pastoris has proven to be an excellent host for the production of both secreted and intracellular proteins. Numerous heterologous proteins have been produced at greater than gram per liter levels using alcohol oxidase promoter. The increasing popularity of this particular expression system can be attributed to several factors, most importantly: the simplicity of techniques for genetic manipulation, the ability to produce foreign proteins at high levels and the capability to perform many posttranslational modifications. The factors that drastically influence protein expression in this system include: copy number of the expression cassette, site and model of chromosomal integration of the heterologous gene, mRNA sequence and secondary structure, transcriptional and translational blocks, nature of secretion signal, endogenous proteases, host strain physiology, media and growth conditions. In this paper, I review how the system was developed, how it works and what can be done about it in the future.
after solvent refining process were used as a carbon source for cultivation of and ATCC 20509. Biomass yield varied from 3.8 g d.m./l to 19.9 g d.m./l and lipids yield varied 1.0 g/l to 10.6 g/l. Lipids utilization in medium varied from 15.0% to 85.4%. Process efficiency, and percentage composition of fatty acids of intracellular lipids and grease remaining in the medium depend first of all on medium composition, type of microorganisms used, temperature and time cultivation.
One of the possibilities of the conservation biology is the in vitro culture method. The usefulness of in vitro culture methods of spore planting and prothallium storage of rare, threatened and protected fern species were tested. Spors of Asplenium adulterinum, A. cuneifolium, A. septentrionale and Polypodium vulgare were collected from sporophytes growing in the natural habitats of Lower Silesia area in 1996. The collected spores were disinfected and the aseptic spores were cultured in flasks containing 1/4 MS solid medium. After three to eight months, the spores germinated, giving rise to a filamentous gametophytes. Six to eight months later, spotophytes could be observed in these cultures. The in vitro method gives the possibility to investigate the special characteristics of life cycle and breeding system of fern species. It is possible to collect fern spores from natural habitats and use them to obtain populations, which will allow to preserve the fern population in cultivation in the Botanical Garden of the Wroclaw University.
The presented data explain why application of immobilized enzyme systems is advantageous in many modern industrial technologies. Also, this reviev article contains information concerning the main methods developed for enzyme immobilization, as well as characteristic, suitability and properties of different carriers used for these purposes. Furthermore, the influence of immobilization process on changes of enzyme activity, selectivity, stability, conditions of catalysed reaction and other properties important in practical applications are described. Emphasis is placed on the choice of immobilized enzyme system adequate for the designed technology.
IGF-I, insulin ? like growth factor I, seems to play a major role in the normal and tumoral development of the nervous system. Glioblastoma is the most frequent brain tumor in man and is usually fatal. Both human and rat glioma cells express high amounts of IGF-I. When rat glioma cells are transfected with vectors expressing either IGF-I antisense RNA or inducing IGF RNA ? DNA triple helix, the synthesis of IGF-I was stopped on translation or transcription levels, respectively. Down-regulation in the expression of IGF-I coincides with the reappearance of B-7 and MHC class I antigens at the surface of transfected cells. When injected subcutaneously, the transfected cancer cells initiate an immune reaction involving CD8+ lymphocytes, followed by tumor regression. The ?anti-gene? strategy for clinical therapy of glioblastoma, and other tumors expressing IGF-I such hepatomas were introduced in University Hospitals of Cleveland (USA), Shanghai ( China) , Krakow and Bydgoszcz (Poland).
The studies conducted during the last decade revealed that RNA molecules play much more different roles in the living world than it had been expected earlier. They can function in biological systems as: carriers of genetic information, enzymes, cofactors inducing or mediating biochemical reactions, inhibitors which deactivate enzymes or agents that regulate cellular processes. Consequently, several new RNA-based methods and techniques have been elaborated. They permit to identify RNA molecules that display some specific properties, selectively induce gene silencing or gene expression in bacterial, plant and animal cells. Generally, it is becoming increasingly apparent that RNA-based technologies should be considered one of the major factors influencing further development of modern biotechnology.
Random Amplified Polymorphic DNAs (RAPD) technique with single primers was tested for its usefulness in genetic distance estimation and population studies in the coniferous species Pinus sylvestris. DNA markers allow for direct analysis both coding and noncoding regions of the genome. The technique of detection DNA variations using RAPD markers has become a popular tool in genetic studies. Different reaction conditions were tested in order to get the optimal resolution of fragments, specificity and reproducibility of patterns. In this preliminary investigation, a high MgCl2 concentration (5,5 mM) together with a low primer concentration (0,2 M) in the polymerase chain reaction (PCR) mixture yielded the best amplification products. Amplified fragments were scored as the presence or absence fragments.
For the development of aseptic culture, Dendrobium kingianum Bidwill orchid pseudobulbs (2.0-3.0 cm long) with one or two terminal leaves were surface sterilized with 0.1% mercuric chloride solution and transferred to initial MS medium, supplemented with auxin IAA at 0.5 mg dm-3 and cytokinin BA at 1.0 mg dm-3. New shoots, which developed after 4-6 weeks of culture at the base of pseudobulbs or at their upper nodes, were transferred to basal MS medium suplemented with an auxin (IAA or NAA) at 0.5 and 1.0 mg dm-3 and cytokinin Kinetin or 6-benzylaminopurine (BA) at 0.5, 1.0 and 2.0 mg dm-3 in different combinations. The responses of orchid cultures varied according to concentrations and type of growth regulators. From tested growth regulators, BA in concentration 2.0 mg dm-3 in combination with 0.5 mg dm-3 IAA was the most effective for shoot induction. At 0.5 mg dm3 both IAA and NAA strongly stimulated shoots multiplication in comparison to 1.0 mg dm-3. NAA-BA combinations positively influenced the shoot length. For roots induction, the NAA-Kinetin combinations were better than the remaining ones. Kinetin stimulated the increase of the root length.
Since 1985, nitrile hydratases, metallo-enzymes present in bacteria from genus Rhodococcous, have been used for industrial production of acrylamide and related chemicals. The unique active site of both Fe- and Co-nitrile hydratases contains oxidized cysteines. Despite many efforts, details of the catalytic mechanism of activity and high selectivity remain unknown. Molecular structures, possible routes of hydration and prospects for applications of these photoactive enzymes in nanotechnology are discussed in this review.
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