Effects of Tween 80 and Freon 113 on Measles Virus

Measles vaccines were prepared from the same virus fluids by inactivation with formaldehyde or by extraction with ether, ethyl acetate, or Freon 113 in the presence of Tween 80. Tests of antigenic potency, based on antibody levels in guinea pigs, showed that the formaldehyde-inactivated vaccines were more potent than the solvent-inactivated preparations and had the additional advantage of long shelf life. Residual Tween 80 in the solvent-extracted vaccines resulted in marked loss of immunogenic potency without significant loss of hemagglutinating activity. Neither extraction with organic solvents nor exhaustive dialysis efficiently removed Tween 80 from aqueous solutions.     

Genduplikation durch polyploide Evolution: die Isoenzyme der Sorbitdehydrogenase bei herings- und lachsartigen Fischen (Isospondyli)

Zusammenfassung Die elektrophoretische Analyse der Isoenzyme der Sorbitdehydrogenase (SDH) bei verschiedenen Säugerspecies unter Einschluß des Menschen läßt darauf schließen, daß bei Säugern nur 1 Genlocus für dieses Enzym existiert. Auch bei Knochenfischen läßt sich in der Regel nur 1 SDH-Gen nachweisen. Eine Ausnahme bilden einige Species der Fischordnung Isospondyli. Innerhalb dieser Ordnung findet sich eine Diploid-tetraploid-Beziehung. Arten mit diploiden Charakteristika wie der Hering (Clupea harengus) besitzen 1 SDH-locus, an dem 3 Allele zu beobachten waren. Bei einigen phylogenetisch tetraploiden lachsartigen Fischen läßt sich eine Duplikation des SDH-Gens nachweisen. Während bei der Bachforelle (Salmo trutta) die nach der Tetraploidisierung zunächst identischen loci sich divergent entwickelt haben und jetzt diploidisiert sind, zeigen Regenbogenforelle (Salmo irideus) und Blaufelchen (Coregonus lavaretus) tetrasome Phänotypen der SDH. Beim Blaufelchen findet sich ein Überschuß an Heterozygoten, der auf eine meiotische Vorzugspaarung der Chromosomen mit identischen Allelen schließen läßt. Diese Befunde geben Einblick in den Mechanismus der Diploidisierung, der in der Evolution der höheren Wirbeltiere eine wesentliche Rolle gespielt haben dürfte.

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Sorbitol dehydrogenase isozymes in clupeoid fish: a further example of gene duplication through polyploid evolution

Summary Electrophoretic analysis of the sorbitol dehydrogenase isozymes (SDH) in various mammalian species including man revealed the existence of only 1 gene locus for this enzyme. As a rule, the same is true for Teleostean fishes. Some species of the fish order Isospondyli, however, represent an exception. Within this order, a diploid-tetraploid relationship exists. Species exhibiting diploid characteristics as the herring (Clupea harengus), are endowed with a single SDH gene locus at which 3 different alleles were observed. In some Salmonoid fish having passed through tetraploid evolution, a duplication of the SDH gene can be demonstrated. While in Salmo trutta the duplicated genes evolved divergently and became diploidized, in Salmo irideus and Coregonus lavaretus tetrasomic phenotypes occur. In Coregonus, the predominance of heterozygotes is to be interpreted as the consequence of preferential pairing of meiotic chromosomes endowed with identical alleles. These findings give some insight in the diploidization mechanism which may have played an important role during evolution of higher vertebrates.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Microbiological studies of Indonesian fermented foodstuffs

Microbiological studies were made of certain Indonesian foodstuffs obtained from Malang, Surakarta, and Djakarta.Saccharomyces cerevisiae andCandida solani were isolated from ragi-roti (a baker's yeast preparation). From ragi-tempe and tempe were isolatedRhizopus oryzae, R. arrhizus, R. oligosporus, R. stolonifer, Mucor Rouxii, M. javanicus andTrichosporon pullulans. The microbiological flora of ragi-tape was found to includeCandida parapsilosis, C. melinii, C. lactosa sp. nov.,Hansenula subpelliculosa, H. anomala, H. malanga sp. nov.,Chlamydomucor oryzae andAspergillus oryzae. From ragi-ketjap, used to prepare soysauce, were isolatedRhizopus oligosporus, R. arrhizus, Aspergillus oryzae, andA. flavus, the latter species probably being an accidental contaminant. Two new species are described:Candida lactosa andHansenula malanga, from ragi-tape from Surakarta and Malang, respectively.From a thesis presented to the Graduate School of Vanderbilt University in partial fulfillment of the requirements for the Ph.D. degree, August, 1969.Financial support of Dakimah Dwidjoseputro by the Ford Foundation is grate-fully acknowledged.     

Yield Coefficients of Thiobacillus neapolitanus in Continuous Culture

Thiobacillus neapolitanus, when grown in continuous culture with thiosulfate limiting growth, possessed an apparent maximal molar growth yield of 8.0 g (dry weight) per mole of thiosulfate. The substrate requirement for energy of maintenance was the highest yet reported, amounting to 21.8 mmoles of thiosulfate per g per hr. The molar growth yield, corrected for this maintenance energy requirement, was 13.9 g (dry weight) per mole of thiosulfate. It was concluded that substrate-level phosphorylation during sulfite oxidation accounted for about 45% of the adenosine triphosphate (ATP) requirement for CO₂ assimilation and maintenance during growth on limiting thiosulfate, that three sites of energy conservation exist in the electron-transport chain terminating in oxygen, and that 7.8 moles of ATP are required to fix and assimilate 1 mole of CO₂ into cell material.     

DIFFERENTIATION OF NEURONAL TYPES AND SYNAPSES IN MYELINATING CULTURES OF MOUSE CEREBELLUM

The Holmes silver impregnation method has made possible the recognition of multiple neuronal types and synapses in myelinating cultures of mouse cerebellum. Well stained large and medium-sized neurons are always found in small numbers near ependymal formations and are considered to be roof nuclear neurons. Neurons with poorly stained somas, abruptly demarked from intensely stained axons, are numerous and often are arranged in palisades. With prolonged maintenance in vitro these neurons develop some but not all of the features of mature Purkinje cells. A few small, densely stained, bipolar neurons, often with one process bifurcated, are found in dense regions of some cultures of newborn cerebellum. These neurons are commoner in cultures from cerebella of older mice. They closely resemble the immature granule cell in vivo. All the neuron types recognized in cultures are present in the initial explants; neurons differentiate further in vitro, but new neurons probably do not form. Synaptic boutons are found on somas and dendrites of many Purkinje cells. Two cultures contained structures resembling the basket endings which surround Purkinje cell somas in vivo. The complexity of neuronal relationships in cultures of central nervous tissue is emphasized.