Establishment of introgression libraries in hybrid rye (Secale cereale L.) from an Iranian primitive accession as a new tool for rye breeding and genomics.

Genetic diversity of elite breeding material can be increased by introgression of exotic germplasm to ensure long-term selection response. The objective of our study was to develop and characterize the first two rye introgression libraries generated by marker-assisted backcrossing and demonstrate their potential application for improving the baking quality of rye. Starting from a cross between inbred line L2053-N (recurrent parent) and a heterozygous Iranian primitive population Altevogt 14160 (donor) two backcross (BC) and three selfing generations were performed to establish introgression libraries A and B. Amplified fragment length polymorphisms (AFLP markers) and simple sequences repeats (SSRs) were employed to select and characterize candidate introgression lines (pre-ILs) from BC(1) to BC2S3. The two introgression libraries comprise each 40 BC2S3 pre-ILs. For analyzing the phenotypic effects of the exotic donor chromosome segment (DCS) we evaluated the per se performance for pentosan and starch content in replicated field trials at each of four locations in 2005 and 2006. Introgression library A and B cover 74 and 59% of the total donor genome, respectively. The pre-ILs contained mostly two to four homozygous DCS, with a mean length of 12.9 cM (A) and 10.0 cM (B). We detected eight (A) and nine (B) pre-ILs with a significant (P<0.05) higher pentosan content and two pre-ILs (B) with a significant (P<0.05) higher starch content than the elite recurrent parent. Thus, our results indicate that exotic genetic resources in rye carry favorable alleles for baking quality traits, which can be exploited for improving the elite breeding material by marker-assisted selection (MAS). These introgression libraries can substantially foster rye breeding programs and provide a promising opportunity to proceed towards functional genomics.

A molecular marker for the identification of Simulium squamosum (Diptera: Simuliidae).

All except one of the important groups of West African vectors of Onchocerca volvulus that lie within the Simulium damnosum complex can be distinguished from each other using morphological characteristics. The exception is S. squamosum, which overlaps with other species, and this results in significant levels of misidentification. Variation in the untranscribed H3-H4 histone intergenic spacer region of flies of the S. damnosum complex has now been investigated. Although a CAA/CAG microsatellite was found to be hyper-variable and unsuitable for species diagnosis, a 10-bp indel seemed to vary in a species-specific manner. This indel was apparently absent from S. squamosum but present in all of the other species tested (S. damnosum s.s., S. sirbanum, S yahense, S. sanctipauli and S. leonense/konkourense). It should now be possible to identify individual, adult, female S. squamosum from the absence of the indel, using a PCR-based amplification and agarose- or polyacrylamide-gel electrophoresis, thus removing the major barrier to the routine identification of unknown samples.

Cytotaxonomy, morphology and molecular systematics of the Bioko form of Simulium yahense (Diptera: Simuliidae).

Cytotaxonomic analysis of the polytene chromosomes from larvae of the Simulium damnosum Theobald complex from the island of Bioko in Equatorial Guinea is reported, and a new endemic cytoform is described. Chromosomally this cytoform is close to both S. squamosum (Enderlein) and S. yahense Vajime & Dunbar, but is not identical to either. However, it is morphologically and enzymatically identical to S. yahense. The Bioko form was also found to differ from other cytoforms of the S. damnosum complex in West Africa in the copy number or RFLP pattern of several different repetitive DNA sequences. It is clear that the Bioko form is genetically distinct from other populations of the S. damnosum complex, and whilst it is closest to S. yahense, it shows features that suggest a high degree of geographical and genetic isolation. Such isolation is an important consideration in the assessment of the potential for onchocerciasis vector eradication on Bioko.

Molecular detection of pathogen DNA in ticks (Acari: Ixodidae): a review.

Ticks play an important role in human and veterinary medicine, in particular due to their ability to transmit a wide spectrum of pathogenic micro-organisms of protozoal, rickettsial, bacterial and viral origin. Pathogens in ticks can be identified by conventional methods such as indirect immunofluorescence, isolation in cell culture or by using histological staining techniques. However, the advent of the polymerase chain reaction (PCR) has resulted in tremendous improvements in the specific and sensitive detection of pathogen DNA in ticks. In this paper, literature on DNA extraction methods, PCR protocols, primers and probes, which are in use for the successful detection and identification of pathogens in ticks, are critically reviewed. Some recommendations are also given towards the end of this review.

Distribution of the Simulium damnosum complex on Bioko island, Equatorial Guinea, and the potential for onchocerciasis elimination by vector eradication.

Onchocerciasis is endemic on the island of Bioko, Equatorial Guinea, where it is transmitted by the 'Bioko form' of the Simulium damnosum complex, a cytospecies unique to the island. To determine the distribution of vector breeding, three dry season and two wet season expeditions were made in 1989, 1996 and 1997, and 226 of the island's 247 rivers (91.5%) were visited. Of these 226 rivers, 130 (58%) were flowing during the dry season, forty-five (20%) supported aquatic stages of Simuliidae of any species and twenty-five (11%) contained larvae or pupae of the S. damnosum complex. The twenty-one rivers not prospected were in the mountainous south of the island, where an additional seventeen rivers were reached but not satisfactorily prospected. Of these thirty-eight rivers, twenty-nine were considered highly likely to support vector breeding, bringing the total number of rivers which could harbour the vector during the dry season to fifty-four (21.9% of the island's total). Breeding was believed to be limited to river stretches below 1000 m altitude, and during the dry season the total length of those stretches which could support breeding on Bioko was estimated to be 1020 km. A combination of factors, including low river discharges during the dry season, the relatively low water temperature on Bioko, the suitability of limited stretches of most rivers as vector breeding sites and the close proximity of many rivers within a small geographical area, render the vector vulnerable to eradication by aerial treatment of rivers with insecticide. The isolation of the Bioko form of the S. damnosum complex suggests that reinvasion following treatment would be unlikely, and eradication of the vector might be achieved by a dry season larviciding programme in one or two years.

[Preparation of drug containing extrusion pellets with a thermoplastic base. 2. The optimization of drug release]. / Darstellung wirkstoffhaltiger Extrusionsformlinge auf der Basis von Thermoplasten. Teil 2: Untersuchungen zur Optimierung der Wirkstofffreigabe.

The drug release can be improved by incorporation of additional auxiliary substances in extrusion pellets. The experimental results proved evidence, that especially the incorporation of calcium carbonate or polyvinylalcohol leads to an increase of the drug release. Their content must amount to 40%. In preparing thermically unstable drugs in pellets, it is necessary to prepare these products under thermically mild conditions. By using ethylene-vinyl-acetate-copolymers these unstable drugs can be incorporated in extrusion pellets.

[Preparation of drugs in extrusion pellets with a thermoplastic base. 1. Drug liberation]. / Darstellung wirkstoffhaltiger Extrusionsformlinge auf der Basis von Thermoplasten. Teil 1: Untersuchungen zur Wirkstoffliberation.

In connection with the preparation of solid sustained-release forms extrusion pellets were prepared. The conditions for the processing of the thermoplastics were determined. Lithium sulfate and caffeine served as model drugs. The drug release from the thermoplastics is insufficient. There was no evidence for a possible relation between the properties of the thermoplastics and the drug release. By means of selected examples a correlation between the thermoplastic capacity to water and the drug release could be found.

[Preparation of peroral delayed-action drug forms using biological polymers as the base. 4. Preparation of erosion tablets with a base of starch hydrolysis products]. / Darstellung peroraler Retardarzneiformen auf der Basis von biologisch abbaubaren Polymeren. 4. Mitteilung: Darstellung von Erosionstabletten auf der Basis eines Stärkehydrolyseproduktes.

The preparation and investigation of erosonic tablets using a modified starch product are described. Codeine phosphate and pholedrine sulfate served as model drugs. The pharmaceutical investigations showed, that this product is a good auxiliary substance for the direct compression. When in contact with water, the tablets form a gel. This gel determines the drug release. In in vitro investigations a degradation of the starch product by enzymes was detected. Especially the amount of the release values obtained were analyzed by the equation of Noyes-Whitney.

[Preparation of preoral sustained-release preparations with a base of biodegradable polymers. 3. Preparation of matrix tablets with a base of poly-3-hydroxybutyric acid]. / Darstellung peroraler Retardarzneiformen auf der Basis von biologisch abbaubaren Polymeren. 3. Mitteilung4: Darstellung von Matrixtabletten auf der Basis von Poly-3-hydroxybuttersäure.

Poly-3-hydroxybutyric acid belongs to the biological polymers, which are produced by bacterials. The determination of the grain size, moisture content, flowability and the parameters for the direct compression was performed in regard of their use as auxillary substance for the preparation of solid sustained release dosage forms. The production of the matrix tablets was performed on the basis of a factorial design. The content of substance, an addition of Heweten 12 and the compression power served as factors. Caffeine was used as model drug. The in vitro release values show, that all three factors have an influence of the drug release. Optimized matrix tablets were produced on the basis of this result.

[Preparation of oral sustained-action preparations with a base of biologically degradable polymers. 2. Preparation of matrix tablets with a base of polylactic acid]. / Darstellung peroraler Retardarzneiformen auf der Basis von biologisch abbaubaren Polymeren. 2. Mitteilung: Dartstellung von Matrixtabletten auf der Basis von Polymilchsäure.

It is reported on the preparation and investigation of matrix tablets on the basis of the polylactic acid. Caffeine and phenazone served as model drugs. The release values obtained were analyzed by the equations of Noyes-Whitney and of Higuchi. It was demonstrated, that the solubility and the grain size of the drugs, their content in the tablets and an addition of Heweten 12 have an influence of the release of the drugs. In in vitro-investigations can be shown a hydrolytic degradation of the polymer, but not an enzymatic degradation.

[Preparation of peroral sustained release drug forms on a base of biodegradable polymers. 1. Preparation and characterization of polylactic acid]. / Darstellung peroraler Retardarzneiformen auf der Basis von biologisch abbaubaren Polymeren. 1. Mitteliung: Darstellung und Charakterisierung von Polymilchsäure.

Biodegradable polymers get more interest for the preparation of drug formulations. Their main advantage is their physiological safety. Polylactic acid is one of the biodegradable polymers. It was prepared by the direct polyesterification of lactic acid and by polymerisation of the cyclic oligomers. Both the polymers were identified by elementary analysis, by IR spectroscopy, by X-ray-test and by the molecular mass. They differ in their molecular mass and in the degree of the crystalline state. The determination of the grain size, moisture content, flowability and of the parameters for the direct compression were carried out with regard to the use of polylactic acid as auxiliary substance for the direct compression. The results show, that polylactic acid which was prepared on the basis of polyesterification, is a very suitable auxiliary substance for the direct compression.

[Preparation and testing of polymer drugs. 4. Water-soluble polymer drugs with a base of vinylpyrrolidone-maleic acid anhydride-copolymers]. / Darstellung und Testung von Polymerpharmaka. 4. Mitteilung: Wasserlösliche Polymerpharmaka auf der Basis von Vinylpyrrolidon-Maleinsäureanhydrid-Copolymeren.

Watersoluble polymeric drugs were synthesized on the basis of alternating copolymer of 1-vinyl-2-pyrrolidone and maleic anhydride. Benzocain served as model drug. The drug was bound directly as well as about epsilon-aminocapronic acid as spacer. The pancreatin catalyzed hydrolysis of these polymeric drugs was studied. No hydrolysis was noted, if the drug is directly bound on the copolymer. The polymeric drug with the epsilon-aminocapronic acid as spacer showed a small release. Possible reasons for these facts are discussed.

[Preparation and testing of polymer drugs. 3. Binding of benzocaine to polyacrylic acid with a spacer]. / Darstellung und Testung von Polymerpharmaka. 3. Mitteilung: Bindung von Benzocain über einen Spacer an Polyacrylsäure.

epsilon-Aminocapronic acid (1) as spacer was introduced in polymeric drugs on the basis of polyacrylic acid. Benzocain served as model drug. Polymeric drugs were synthesized by copolymerisation with free acrylic acid. Not all functional groups of the carrier reacted with the model drug. This product showed a strong swelling during the release of the covalently bound drugs. Pancreatin was used for this investigation. A raising of the splitting rate was achieved by incorporation of the spacer in the polymeric drugs. However, the low rate of cleaving is not relevant for practical use.

[The control of drug release of heavy-soluble, weak basic drugs in matrix tablets using the example of medazepam]. / Zur Steuerung der Arzneistofffreigabe schwerlöslicher, schwach basischer Arzneistoffe aus Matrixtabletten am Beispiel von Medazepam.

According to ideas about the diffusion layer in the process of dissolving solids the release of medazepam as a model substance for heavy-soluble, weak alkaline substances is modified by incorporation of solid acids of different solubility and dissociation rate into the matrix. The determination of the solubility and a "virtual" pH-value within the matrix tablets leads to the evaluation of the liberation. A relatively continuous release of medazepam following different pH-values in the medium was obtained by microencapsulation of the citrus acid incorporated. Using the ideas of the diffusion layer to explain the conditions within the matrix it becomes possible to control and influence the drug release from the matrix tablet.

[Preparations of matrix tablets from a polyacrylate base]. / Darstellung von Matrixtabletten auf der Basis von Polyacrylaten.

The authors report with the example of the model drug, caffeine, on the preparation and investigation of matrix tablets on the basis of acrylates. The release values obtained were analysed by the equations of Higuchi and also Noyes-Whitney. It was demonstrated, that the polymer composition and the drug content in the tablets have an influence on the release of the drug.