Biophysical and Biochemical Studies on Rhinovirus and Poliovirus II. Chemical and Hydrodynamic Analysis of the Rhinovirion

Chemical analysis of rhinovirus 14 revealed a ribonucleic acid (RNA) content of 29.8% and a high adenylic acid content (35%). A partial specific volume of 0.682 cm³/g was obtained for the rhinovirion. Rhinovirus and poliovirus had identical sedimentation coefficients of 158S. A diffusion coefficient of 1.71 × 10⁻⁷ cm²/sec was consistent with a hydrated diameter of 25 nm for the rhinovirion. The calculated molecular weights of the rhinovirion and its genome were 7.1 × 10⁶ and 2.1 × 10⁶ daltons, respectively. Sedimentation analysis of infectious RNA confirmed the similarity of the molecular size of the poliovirus and rhinovirus genomes.     

The Behaviour of Dasyuroides byrnei (Marsupialia) in Captivity

Das Verhalten des Beuteltiers Dasyuroides byrnei in Gefangenschaft wurde untersucht. Dasyuroides ist nachtaktiv und verbirgt sich tagsüber in einem Bau oder Schlupfwinkel. Körperhaltung, Fortbewegungsarten, Höhlengraben, Beutefang und andere Verhaltensweisen sind beschrieben. Das Duftmarkieren hat Mitteilungswert. Beide Geschlechter setzen Duftstoff ab, indem sie ihre Sternaldrüsen und Kloakengegend an Gegenständen reiben. Freundschaftliche, kämpferische, sexuelle und mütterliche Verhaltensweisen werden beschrieben. Dasyuroides scheint kein geselliges Tier zu sein; Angriffe gegen Artgenossen führen selten zu Verletzungen, weil das Angriffsverhalten stark stilisiert ist. Wachstum und Entwicklung der Jungen wurden verfolgt. Die durchschnittliche Wurfgröße beträgt fünf oder sechs; die Jungen bleiben an den Zitzen des ♀ bis zum 56. Lebenstag. Mit 100 Tagen können sie entwöhnt werden. Das Verhalten dieser Art wird mit anderen Arten der Familie Dasyuridae verglichen, auch mit Plazentaliern.     

Deoxyribonucleic Acid of Adeno-associated Satellite Virus

Staining patterns suggest that in the adeno-associated satellite virion there exist quasi single-stranded regions which are renatured after extraction to exhibit double strandedness.     

Physical Assay and Growth Cycle Studies of a Defective Adeno-Satellite Virus

Electron microscopic particle counting of the defective adeno-satellite virus (ASV), by use of pseudoreplication and negative staining with phosphotungstic acid, was shown to be a reproducible quantitative assay procedure. Particles of satellite type 4 that were counted in fluids from infected cultures had the same morphology as particles that banded at a buoyant density of 1.43 g/cc in cesium chloride. Other satellite virus serotypes examined in the same manner had a buoyant density of 1.37 to 1.38 g/cc. A comparison of satellite titers obtained by complement fixation and by particle counting demonstrated that an increase in satellite particles resulted in a corresponding increase in CF titers; however, electron microscopy was at least 10 times more sensitive than complement fixation for detecting satellite virus. Growth cycle studies of satellite virus in cells co-infected with adenovirus, as assayed by particle counting, indicated that the kinetics of satellite virus production closely followed the kinetics of its helper adenovirus production, with an eclipse period of 12 to 16 hr. The eclipse period of the satellite remained the same when cultures were preinfected with satellite 24 hr prior to adenovirus inoculation. However, when cultures were infected with adenovirus 12 hr before satellite virus, the eclipse period of the satellite was shortened to between 4 and 6 hr. Thus, satellite virus replication seems dependent upon a relatively late event in the adenovirus replication cycle. When cells were co-infected with adenovirus and its defective satellite, the yield of adenovirus was markedly reduced from that obtained in cells singly infected with adenovirus.     

AN ULTRASTRUCTURAL STUDY OF THE GIANT GREEN ALGAL COENOCYTE, CAULERPA PROLIFERA

The general fine structure of the giant coenocyte Caulerpa prolifera (Forsskål) Lamouroux is presented. The cytoplasm forms a parietal layer throughout the plant without any regular membranous separations within organs or between organs. The vacuome is similar in structure. There are distinct patterns of organelle distribution in the highly polar cytoplasm of rhizoids and blades. The organelles are compared to those of other members of the division Chlorophyta and are typical. Amyloplast structure is compared to that of chloroplasts. A possible developmental sequence from chloroplast buds through an unusual circular body is suggested.     

Sucrose utilization by Zymomonas mobilis: formation of a levan

1. Molar growth-yield coefficients of Zymomonas mobilis for glucose, fructose, glucose plus fructose, and sucrose are reported. Yield coefficients for sucrose are appreciably lower than those for the equivalent concentrations of glucose plus fructose. 2. Only 2.6% of [U-(14)C]glucose supplied in the growth medium is incorporated into cell substance by Z. mobilis utilizing glucose as the energy source. 3. During growth on sucrose a levan is formed. It has been characterized and shown to resemble other bacterial levans. 4. Levan formation from sucrose could be demonstrated with both washed cell suspensions and cell extracts of Z. mobilis. 5. Sucrose phosphorylase could not be demonstrated in extracts of the organism.     

Studies on the endogenous metabolism and senescence of starved Sarcina lutea

1. When washed suspensions of Sarcina lutea are starved aerobically in phosphate buffer at the growth temperature of 37 degrees , the rate of endogenous oxygen consumption decreases to very low values after 10hr., although many of the cells survive for 40hr. If starvation is prolonged further, the bacteria die at a rate of approximately 1.5% of the initial viable population per hour. 2. Oxidation of intracellular free amino acids accounts for most of the observed endogenous oxygen uptake but RNA is also utilized and a portion of the component bases and pentose is degraded and presumably oxidized. Ammonia appears in the supernatant and some pentose and ultraviolet-absorbing nucleotide are released from the cells. DNA, protein and polysaccharide are not measurably degraded. 3. Survival can be correlated with the ability of aerobically starved bacteria to oxidize exogenous l-glutamate and glucose. When starved under nitrogen for 40hr. cells continue to oxidize their endogenous reserves at undiminished rates when transferred to aerobic conditions; on prolonging anaerobic starvation the rate of oxidation declines during the period of most rapid loss of viability. 4. In the presence of Mg(2+), RNA degradation during aerobic starvation is almost completely suppressed without affecting the period for which the bacteria survive. 5. Cells grown in peptone supplemented with glucose accumulate reserves of polysaccharide which are metabolized in aerobic starvation, together with free amino acids. Ammonia is evolved and RNA is degraded to a greater extent than in peptone-grown suspensions. Bacteria rich in polysaccharide survive less well than those which are deficient in the polymer; the reason for this phenomenon has yet to be established. 6. In peptone medium, endogenous oxygen uptake and the concentration of intracellular free amino acids decline as growth progresses and they continue to decrease when the organism is held in stationary phase. Under the conditions used, the endogenous Q(o2) and free amino acid pool of cells grown in peptone with 2% (w/v) glucose did not decline so markedly and the bacteria contained large amounts of polysaccharide at all stages of growth.     

Tissue culture of Ecklonia radiata (Phaeophyceae,Laminariales): effects on growth of light,organic carbon source and vitamins

The effects of light quality and irradiance, and supply of organic carbon and vitamins on the growth of two forms of Ecklonia radiata in tissue culture were examined. A callus of unpigmented cells developed over the cut surface of newly excised explants of stipe. This growth was best in the dark but stopped after 10 weeks. Pigmented, mainly filamentous clumps of cells developed from explants after several weeks in culture. These required light for growth, with growth being enhanced by increasing photon flux density up to 30 μmol photon m^-2 s^-1, with the active spectral component being red light (> 600 nm). The addition to the medium of a range of organic carbon sources or vitamins did not stimulate growth of either culture type in the dark. author for correspondence