Oxygen binding properties,capillary densities and heart weights in high altitude camelids

Summary The oxygen binding properties of the blood of the camelid species vicuna, llama, alpaca and dromedary camel were measured and evaluated with respect to interspecific differences. The highest blood oxygen affinity, not only among camelids but of all mammals investigated so far, was found in the vicuna (P₅₀=17.6 Torr compared to 20.3–21.6 Torr in the other species). Low hematocrits (23–34%) and small red blood cells (21–30 m³) are common features of all camelids, but the lowest values are found in theLama species. Capillary densities were determined in heart and soleus muscle of vicuna and llama. Again, the vicuna shows exceptional values (3720 cap/mm² on average in the heart) for a mammal of this body size. Finally, heart weight as percent of body weight is higher in the vicuna (0.7–0.9%) than in the other camelids studied (0.5–0.7%). The possibility that these parameters, measured in New World tylopodes at sea level, are not likely to change considerably with transfer to high altitude, is discussed.In the vicuna, a unique combination of the following features seems to be responsible for an out-standing physical capability at high altitude: saturation of blood with oxygen in the lung is favored by a high blood oxygen affinity, oxygen supply being facilitated by low diffusion distances in the muscle tissue. Loading, as well as unloading, of oxygen is improved by a relatively high oxygen transfer conductance of the red blood cells, which is due to their small size and which compensates the negative effect of a low hematocrit on the oxygen conductance of blood. Blood oxygen transport is presumably favored by two factors: a relatively large heart mass and, as a result of low hematocrit, a low blood viscosity. Both are advantageous for achieving a high maximal cardiac output.     

Cytogenetische und cytologische Befunde bei enzymopenischen Panmyelopathien und Pancytopenien

Ohne ZusammenfassungDirektor: Prof. Dr. F. Vogel Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Quantitative and qualitative assay of amniotic-fluid acetylcholinesterase in the prenatal diagnosis of neural tube defects

Summary In 110 amniotic fluids the specific acetylcholinesterase was determined quantitatively and qualitatively. In the quantitative assay there were a considerable number of false positives and false negatives, although the mean value of the normal controls differed significantly from that of neural tube defect pregnancies. By the electrophoretic separation of acetylcholinesterase, however, all fluid samples with borderline alpha-fetoprotein levels or fetal blood contamination could be correctly classified. With the exception of one skin-covered spina bifida all neural tube defects in the second trimester could be identified by this method. The second fast-moving band characteristic of the specific acetylcholinesterase was also present in abdominal wall defects and intrauterine death.     

Position of chromosomes in the human interphase nucleus

Summary The problem of localization of chromosomes in relation to each other in the interphase nucleus of human lymphocytes was investigated by analysis of chromatid and chromosome aberrations observed in lymphocyte cultures of three patients with Fanconi's anemia, one patient with Bloom's syndrome, and in Trenimon-treated (Trenimon, Bayer) normal cells. Distribution of open gaps and breaks is highly correlated with chromosome length and distribution of breaks involved in chromatid translocations in Fanconi's anemia and in Trenimontreated cells. Both correlations are much lower in Bloom's syndrome. In Fanconi's anemia and in normal cells after Trenimon-treatment, the majority of chromatid translocations are between nonhomologous chromosomes, whereas in Bloom's syndrome mainly homologous chromosomes are involved. Statistical localization of chromosomes in relation to each other in the three-dimensional space by multidimensional scaling gives results consistent with the limited amount of independent evidence.     

Studies on the evolutionary relationships between hemoglobins inChironomus pallidivittatus andC. Tentans

Summary The monomeric hemoglobins ofChironomus tentans andC. pallidivittatus have been isolated and separated into their respective components by gel chromatography on Sephadex G-75 and ion-exchange chromatography on DEAE-Sephacel. The amino acid compositions of the purified components are given. The sequence of the 30 N-terminal amino acid residues of one of the monomeric components (Hb I fromC. pallidivittatus) was determined and found to be identical in almost all of its parts with the monomeric hemoglobins ofC. thummi (CTT III and CTT IV).Antibodies against the monomeric hemoglobins Hb I and Hb IIc and the dimeric fraction were highly specific and no cross reaction between dimeric and monomeric hemoglobins could be demonstrated. The antibodies against the monomers crossreact with the monomeric hemoglobins CTT III and CTT IV ofC. thummi. Taken together with genetic data, the immunological results indicate that divergence of monomeric from dimeric forms was an early event in the evolution of the various hemoglobins inChironomus.     

Zellteilung und Kappensysteme der Oedogonien

Ohne Zusammenfassung     

Multiple-locus variable-number tandem-repeats analysis of Salmonella enterica subsp. enterica serovar Typhimurium using PCR multiplexing and multicolor capillary electrophoresis

The multiple-locus variable-number tandem-repeats analysis (MLVA) method is currently being used as the primary typing tool for Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) isolates in our laboratory. Our published initial MLVA was performed using a single fluorescent dye and the different patterns were assigned from gel images. Here we present a new and significantly improved assay using multiple dye colors, enhanced PCR multiplexing and the introduction of two new loci for better adaptation to capillary electrophoresis with increased speed. The different MLVA patterns are now based on allele sizes entered as character values, thus removing the uncertainties introduced when analyzing band patterns from gel images. We additionally propose an easy numbering scheme for the identification of separate isolates that will facilitate exchange of typing data. A total of 106 human, bird, animal and food isolates of S. Typhimurium, including 16 with definite type (DT) 104, were used for the development of the improved MLVA. The method is based on capillary separation of multiplexed PCR products from five VNTR loci in the S. Typhimurium genome labeled with multiple fluorescent dyes. The different alleles at each locus were then assigned allele numbers, which were used for strain comparison.     

Study of polymorphic variable-number of tandem repeats loci in the ECOR collection and in a set of pathogenic Escherichia coli and Shigella isolates for use in a genotyping assay

The Escherichia coli (E. coli) reference collection, ECOR, consists of 72 strains that are representative of the genotypic diversity, as indexed by multilocus enzyme electrophoresis (MLEE), in the species as a whole. MLEE revealed 4 main phylogenetic groups designated A, B1, B2 and D. We present a study of the relationship between the ECOR strains as determined by polymorphisms in seven variable-number of tandem repeats (VNTR) loci. Seven tandem repeats that were present in more than one of the fully sequenced E. coli strains were selected, and primers were constructed in order to amplify the targets in all species where the loci were present. The combined result for all VNTR loci was adapted as a multiple-locus variable-number tandem repeats analysis (MLVA) and showed that the ECOR collection was divided into 63 distinct genotypes. The ECOR phylogenetic groups defined by MLEE were not well conserved by MLVA. A set of 61 pathogenic isolates of both E. coli and Shigella spp. was then tested with the same set of VNTR loci, and revealed 54 distinct genotypes. In addition, the MLVA method was used to genotype isolates from patients and suspected sources in a recent outbreak of E. coli O103 in Norway. The pathogenic E. coli isolates contained the diarrhea causing categories EIEC, EAEC, STEC, ETEC and EPEC. Shigella isolates were of species S. flexneri, S. boydii, S. sonnei and S. dysenteriae. The MLVA method rapidly genotyped all isolates in the study at a Simpson's index of diversity of D=0.98.     

Neuropeptide profiling of the bovine hypothalamus: thermal stabilization is an effective tool in inhibiting post-mortem degradation

The hypothalamus is the central regulatory region of the brain that links the nervous system to the endocrine system via the pituitary gland. It synthesizes and secretes neuropeptide hormones, which in turn act to stimulate or inhibit the secretion of pituitary hormones. We have undertaken a detailed MS investigation of the peptides present in the bovine hypothalamus by adapting a novel heat stabilization methodology, which improved peptide discovery to direct our studies into the molecular mechanisms involved in bovine reproduction. The untreated samples contained large numbers of protein degradation products that interfered with the analysis of the neuropeptides. In the thermally stabilized samples, we were able to identify many more neuropeptides that are known to be expressed in the bovine hypothalamus. Furthermore, we have characterized a range of post-translational modifications that indicate the presence of processed intact mature neuropeptides in the stabilized tissue samples, whereas we detected many trimmed or truncated peptides resulting from post-mortem degradation in the untreated tissue samples. Altogether, using an optimized workflow, we were able to identify 140 candidate neuropeptides. We also nominate six new candidate neuropeptides derived from proSAAS, secretogranin-2 and proTRH.