Phosphoproteins in dictyostelium discoideum

The phosphoproteins of Dictyostelium discoideum were compared at different stages of development by polyacrylamide gel electrophoresis. Certain phosphoproteins of vegetative amoebae were conserved while others appeared and disappeared during development. Four major phosphoproteins with apparent subunit molecular weights of 50,000, 47,000, 38,000, and 34,000 disappeared precociously in response to exogenous cAMP. Two membranal phosphoproteins, with apparent subunit molecular weights of 80,000 and 81,000, appeared precociously in response to added cAMP. One of these phosphoproteins, molecular weight of 80,000, has been identified tentatively as the “contact site A” glycoprotein. Another membranal protein, with apparent subunit molecular weight of 42,000, unaffected in its appearance by cAMP, has been identified tentatively as phosphoactin.     

Assay of zofenopril and its active metabolite zofenoprilat by liquid chromatography coupled with tandem mass spectrometry

Zofenopril is a pro-drug designed to undergo metabolic hydrolysis yielding the active free sulfhydryl compound zofenoprilat, which is an angiotensin converting enzyme (ACE) inhibitor, endowed also with a marked cardioprotective activity. A simple, highly sensitive specific LC–MS–MS method was developed for the determination of zofenopril and zofenoprilat in human plasma. In order to prevent oxidative degradation of zofenoprilat and its internal standard, their free sulfhydryl groups were protected by treatment with N-ethylmaleimide (NEM), which produced the succinimide derivatives. The compounds and their corresponding fluorine derivatives, used as internal standards, were extracted from plasma with toluene. The reconstituted dried extracts were chromatographed and then monitored by a triple-stage-quadrupole instrument operating in the negative ion spray ionization mode. The method was validated over the concentration range of 1–300 ng/ml for zofenopril and 2–600 ng/ml for zofenoprilat. Inter- and intra-assay precision and accuracy of both zofenopril and zofenoprilat were better than 10%. The limit of quantitation was 1 ng/ml with zofenopril and 2 ng/ml with zofenoprilat. Extraction recovery proved to be on average 84.8% with zofenopril and 70.1% with zofenoprilat. Similar recoveries were shown by the above two internal standards. The method was applied to measure plasma concentrations of zofenopril and zofenoprilat in 18 healthy volunteers treated orally with zofenopril calcium salt at the dose of 60 mg.     

Hierarchy of effects of the MHC and T cell receptor beta-chain genes in susceptibility to Theiler's murine encephalomyelitis virus-induced demyelinating disease.

Intracerebral inoculation of susceptible mice with Theiler's murine encephalomyelitis virus induces a demyelinating disease that is similar to human multiple sclerosis. This murine model for human multiple sclerosis is apparently immune-mediated and the genes involved in the immune response influence the outcome of disease susceptibility as observed with human multiple sclerosis. These genes include the MHC and TCR genes. However, the functional relationships among these genes on the disease susceptibility has not yet been studied. In this study, we demonstrate that the effect of the H-2s genotype from susceptible SJL/J mice overrides the resistant effect of the BALB/c TCR beta-chain gene in CXJ recombinant-inbred and BALB.S congenic mice. These results strongly suggest the presence of a hierarchy of genes involved in the immune response in Theiler's murine encephalomyelitis virus-induced demyelinating disease.     

Evolutionary relationships among hares from North Africa (Lepus sp. or Lepus spp.), cape hares (L. capensis) from South Africa, and brown hares (L. europaeus), as inferred from mtDNA PCR-RFLP and allozyme data

Systematics and taxonomy of hares of the genus Lepus (Lagomorpha) are under contentious debate, and phylogenetic relationships among many taxa are not well understood. Here we study genetic differentiation and evolutionary relationships among North African hares, currently considered subspecies of Lepus capensis , cape hares ( L. capensis ) from the Cape province in South Africa, and brown hares ( L. europeaus ) from Europe and Anatolia, using maternally (mtDNA) and biparentally (allozymes) inherited markers. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of a c. 1.8 kb long segment of the mitochondrial control region using eight hexanucleotide-recognizing restriction endonucleases yielded 28 haplotypes, and horizontal starch gel electrophoresis of proteins encoded by 25 structural gene loci revealed 52 alleles at 18 polymorphic loci. Diverse phylogenetic analyses (neighbor joining dendrogram, median joining network, multidimensional scaling of pairwise distances, AMOVA, F -statistics, hierarchical F -statistics) of genetic variants revealed marked substructuring of mtDNA into three phylogeographic groups, namely an African, a central European, and an Anatolian, but a somewhat less pronounced overall differentiation of the nuclear genome, despite a relatively high number of population-specific (private) alleles. However, all our results are not incongruent with Petter's (1959: Mammalia 23 , 41; 1961: Z. f. Säugetierkunde 26 , 30; 1972 : Société Des Sciences Naturelles et Physiques du Maroc 52 , 122) hypothesis that North African hares generally belong to L. capensis and that brown hares should be included in this species as well.     

Effect of Zeitgeber Intensity Reduction on a Simulated Dual-Oscillator Human Circadian System: Classical and Dynamic Analysis

The two-oscillator model of human circadian rhythmicity was analyzed when a zeitgeber relative intensity of 1, 0.5, or 0.1 was introduced into the equations. Fourier analysis was compared with dynamic analysis such as attractor reconstruction or Liapunov exponent calculation. After a 50 or 90% reduction in zeitgeber intensity, the dynamics of the system became equivalent and differed significantly from those of a system with maximal zeitgeber intensity. When 10% aleatory noise was added to the data, the analysis was still applicable, and the results obtained were essentially the same as in the absence of noise. Dynamic analysis could thus provide a distinct classification for periodic data, based on the type of analysis.     

Nucleotide sequence and evolution of the orangutan ε globin gene region and surrounding Alu repeats

Summary We have mapped and sequenced the globin gene and seven surrounding Alu repeat sequences in the orangutan globin gene cluster and have compared these and other orangutan sequences to orthologously related human sequences. Noncoding flanking and intron sequences, synonymous sites of , , and globin coding regions, and Alu sequences in human and orangutan diverge by 3.2%, 2.7%, and 3.7%, respectively. These values compare to 3.6% from DNA hybridizations and 3.4% from the globin gene region. If as suggested by fossil evidence and molecular clock calculations, human and orangutan lineages diverged about 10–15 MYA, the rate of noncoding DNA evolution in the two species is 1.0–1.5×10^–9 substitutions per site per year. We found no evidence for either the addition or deletion of Alu sequences from the globin gene cluster nor is there any evidence for recent concerted evolution among the Alu sequences examined. Both phylogenetic and phenetic distance analyses suggest that Alu sequences within the and globin gene clusters arose close to the time of simian and prosimian primate divergence (about 50–60 MYA). We conclude that Alu sequences have been evolving at the rate typical of noncoding DNA for the majority of primate history.Presented at the FEBS Symposium on Genome Organization and Evolution, held in Crete, Greece, September 1–5, 1986     

Analysis of the shape of P vs I curves of a natural phytoplankton assemblage during the year in the mesotrophic Lake Maarsseveen (I), The Netherlands

Production versus light response curves were made of natural phytoplankton assemblages during the year in an incubator at 8 different light intensities ranging from 60 to 1500 Einstein.m^–2.sec^–1. The shape of these curves is analyzed in relation to the sensitivity for photo-inhibition. At the end of the month of April, there is a sudden shift in this sensitivity at higher light intensities. The algal assemblage becomes less sensitive for photo-inhibition. The influence of light-adaptation, temperature, nutrient limitation and species composition is discussed.     

Effect of liposome encapsulation on antigen presentation in vitro. Comparison of presentation by peritoneal macrophages and B cell tumors

We have studied the effect of liposome encapsulation of pigeon cytochrome-c (PCC) on its processing and presentation by peritoneal exudate cells and B-cell hybridomas to antigen specific T cells in vitro. Encapsulation of PCC in liposomes modestly increased the presentation when the macrophage was the presenting cell but totally eliminated presentation when the B cell hybridoma was the presenting cell as determined by the IL-2 response. Using radiolabeled PCC, the increased presentation by the macrophage was correlated with an increase in the uptake and rate of processing of the liposomal antigen. The elimination of presentation by the B cell was due to the inability of this cell type to internalize and degrade the encapsulated PCC. The results support the concept that the macrophage is the primary cell type involved in the initial stages of an immune response to a liposome encapsulated protein Ag in vivo.