Nuclear columns: labeling and release of virus specific RNA by nuclei of DNA-virus (SV 40) infected cells

Lipopolysaccharide and an acidic polysaccharide were extracted with phenol-water from a rough strain of $\text{Escherichia coli}$ (LP1092). The polysaccharide portion of lipopolysaccharide contained galactose, glucose, L-glycero-D-mannoheptose, small amounts of mannose and an unusually high proportion of 3-deoxy-D-manno-octulosonic acid; this polysaccharide was shown to represent the complete $\text{coli}$ R2 core. The acidic polysaccharide, which functioned as a K antigen, contained large amounts of a 2-keto-3-deoxy sugar acid. On colorimetric and chromatographic evidence this acid appeared to be 3-deoxy-D-manno-octulosonic acid.     

Capsule degradation in azotobacter

Enzymic degradation of $\text{Azotobacter}$ capsular polysaccharide by the depolymerases from azotophage lysates of $\text{A}$. $\text{vinelandii}$, and from a strain of $\text{A}$. $\text{chroococcum}$ was examined. The molecular size of the capsular polysaccharide was examined by molecular sieve chromatography both before and after exposure to the capsule depolymerase. The depolymerase appears to attack the polysaccharide substrate in a random fashion which results in polysaccharide fragments of a random size distribution. The ester linkages and hexuronic acids were proportionally the same in all fractions before degradation, but ester linkages were absent from the smaller polysaccharide molecules after enzyme action. The ester linkages were not the substrate bonds broken by the enzyme, but, in the case of some azotophage enzymes, they appeared to play a role in enzyme activity, possibly as recognition sites.     

Interaction of phenol with the polysaccharide of bacteria cell wall

Phenol forms an insoluble complex with the polysaccharide in the cell wall of $\text{M.}$$\text{lysodeicticus}$, and renders it resistant to the action of lysozyme. The formation of the stable complex in the wall accounts for the bactericidal action of phenol. The application of lysozyme in this study affords a unique means of measuring the rate and degree of reaction between phenol and the polysaccharide.     

Analysis of the acid polysaccharides from squid cranial cartilage and examination of a novel polysaccharide

The polysaccharides of cranical cartilge were isolated by ethanol precipitation after papain digestion and β-elimination procedures and were fractionated chromatographically on CPC-cellulose. In addition to the previously described, heavily oversulphated chondroitin sulphate, the tissue contained small amounts of hyaluronic acid, which, however, co-eluted with the chondroitin sulphate from the CPC-cellulose. Approx. 20% of the isolated polysaccharides consisted of an acidic polysaccharide which to our knowledge is not previously described. This polysaccharide consists mainly of glucuronic acid, galactose and mannose in a molar ratio of 1:2:1. Gel chromatography of the preparation indicated a polydisperse molecule with an apparent average molecular weight of 39200 on weight basis $\text{(}\text{M}{}_{\mathrm{<mtext>w</mtext>}}\text{)}$ and 31400 on number basis $\text{(}\text{M}{}_{\mathrm{<mtext>n</mtext>}}\text{)}$.     

Characterization of 3-deoxy-D-manno-octulosonic acid as a component of the capsular polysaccharide antigen from Neisseria meningitidis serogroup 29-e

3-deoxy-$\text{D}$-$\text{manno}$ acid (KDO) has been characterised as the major component (53%) of the capsular polysaccharide antigen of $\text{N}\text{. meningitidis}$ serogroup 29-e. This is the first reported occurrence of KDO in any biological polymer other than its well established occurrence in the lipopolysaccharides of gram-negative bacteria.     

Roles of sodium and potassium ions on p-aminohippurate transport in rabbit kidney slices

This investigation was principally undertaken to test the ionic gradient hypothesis as applied to active $\text{p-}\text{aminohippurate}$ uptake in the rabbit kidney cortical slice preparation. Efflux of $\text{p-}\text{aminohippurate}$ from the slice was shown to be independent of external Na⁺ concentration. Transferring slices from a low sodium preincubation to a high sodium incubation medium containing $\text{p-}\text{aminohippurate}$ increased intracellular concentrations of both Na⁺ and K⁺, and $\text{p-}\text{aminohippurate}$ accumulation occurred. Transferring slices from a low sodium preincubation to a high sodium incubation medium containing ouabain and $\text{p-}\text{aminohippurate}$ resulted in a net increase in intracellular Na⁺ concentration but no $\text{p-}\text{aminohippurate}$ accumulation occurred. Different combinations of preincubation and incubation media gave a high to low array of intracellular Na⁺ concentrations and these directly reflected their respective $\text{p-}\text{aminohippurate}$ uptake. These results suggest that the Na⁺-gradient hypothesis does not adequately explain the transport of organic acids in rabbit kidney. These results also suggest that Na⁺ possibly has an intracellular role through its stimulation of $\text{(Na}{}^{\mathrm{+}}\text{+ K}{}^{\mathrm{+}}\text{)-ATPase}$ channeled to energizing the $\text{p-}\text{aminohippurate}$ accumulative mechanism.     

Structure of the capsular polysaccharide (K6-antigen) from Escherichia coli LP 1092

The linkage pattern of the K6-antigen was investigated using material from the urinary pathogen, $\text{Escherichia coli}$ LP 1092. The polysaccharide consists of ribose and 3-deoxy-$\text{D}\text{-}\text{manno}$-2-octulosonate (KDO) in a ratio of 2:1. Colorimetric procedures, Smith degradation, methylation analysis, and nuclear magnetic resonance spectroscopy were applied to the whole polysaccharide and to a trisaccharide “repeating unit” obtained by mild-acid catalyzed hydrolysis. Together, the data are compatible only with a branched chain structure …$\text{3Rib}\text{f}\text{β1→7KDO}\text{p}\text{β2→3Rib}\text{f}\text{β}$…

     

Regulation of glutamate synthase from Bacillussubtilis by Glutamine

Glutamate synthase, an important enzyme in the assimilation of ammonia, was measured in cultures of $\text{Bacillus}\text{subtilis}$ grown with different nitrogen sources. An attempt was made to correlate the specific activity to the intracellular levels of five metabolites of glutamate metabolism: aspartate, glutamate, glutamine, alanine and $\text{NH}{}_4{}^{\mathrm{+}}$. An inverse relationship was found between the activity of glutamate synthase and the pool level of glutamine. We propose that the intracellular concentration of glutamine is an important element in controlling the level of glutamate synthase.     

Gene m3 mediated efflux of intracellular leucine from bacteriophage P22 infected Salmonella typhimurium

Infection of $\text{Salmonella}\text{typhimurium}$ with the $\text{m}{}_3$ mutant of bacteriophage P22 leads to a rapid and severe efflux of intracellular leucine. The superinfection exclusion ($\text{sie}$) genes of P22 interfere with the function of $\text{m}{}_3$ gene, the product(s) of which is speculated to be an internal protein of phage P22.     

Correlation of the perceived texture of random coil polysaccharide solutions with objective parameters

A wide range of concentrated random coil polysaccharide solutions have been assessed for textural attributes by a trained sensory panel. The only textural terms invoked to describe these model systems were ‘thickness’ and ‘stickiness’, which were shown to be highly correlated, and essentially identical numerically, using a ratio scaling technique. Viscosity (η) measurements over a wide range of shear rates (γ) for all these samples gave flow curves (log η versus log γ) of the same form. Differences in flow behaviour between samples could then be characterised completely by two parameters, the maximum viscosity at low shear rates (η₀), and the shear rate ($\text{γ}\text{?}{}_{\mathrm{0·1}}$) at which $\text{η =}\text{solη}{}_0\text{10}$. A simple linear relationship was demonstrated between these two parameters and perceived thickness (T) or stickiness (S), irrespective of polysaccharide type. For Newtonian liquids, log T (or log S) varied linearly with log η. Hence the effective ‘in-mouth’ thickness of random coil polysaccharide solutions, in normal viscosity units, may be predicted directly from η₀ and $\text{γ}\text{?}{}_{\mathrm{0·1}}$ by the simple relationship: $\text{log}\text{η}{}_{\mathrm{N}}\text{= 1·13}\text{log}\text{η}{}_0\text{+ 0·45}\text{log}\text{γ}\text{?}{}_{\mathrm{0·1}}\text{? 1·72}$ where η_N is the viscosity of a Newtonian solution which would be perceived as identical in thickness (and stickiness) to the polysaccharide solution.     

Protease secretion in Neurospora crassa

Secreted and constitutive intracellular proteases of $\text{Neurospora crassa}$ differ with regard to inhibitor sensitivity, substrate specificity, isoelectric points and other properties. Upon the induction of protease secretion the enzymes released from the mycelium are formed $\text{de novo}$ as demonstrated by density labelling with D₂O. Vesicles which contain the constitutive intracellular proteases are, therefore, not involved in the secretion of proteases.     

The intracellular location of hepatic fructose 1,6-biphosphate aldolase.

Foemmel $\text{et}\text{al.}$ (J. Biol. Chem. $\text{250}$, 1892–1897, 1975) have presented evidence that rat liver aldolase exists $\text{in}\text{situ}$ as a specific complex with the endoplasmic reticulum. In the present study we have examined the alternative possibility that binding of enzyme to the particulate element represents an artifact of the dilution of the ionic constituents of the cytoplasmic milieu. To this end, procedures were developed for homogenization and subfractionation which effected less than a 3-fold dilution of the intracellular content. Using these procedures, virtually all of the liver aldolase was recovered in the soluble supernatant fraction. We conclude that aldolase is not associated with the endoplasmic reticulum $\text{in}\text{situ}$.     

Modification of radiosensitivity of mammalian cells by cyclic nucleotides

Some $\text{in vitro}$ and $\text{in vivo}$ studies suggest that adesosine 3′,5′-cyclic monophosphate (cyclic AMP) may be one of the important factors in determining the radiosensitivity of certain mammalian cells; however, the role of guanosine 3',5'-cyclic monophosphate (cyclic GMP) in radiosensitivity of mammalian cells is completely unknown. Recent data also suggest that the mechanism of radiation protection afforded by moderate hypoxia and SH-containing compounds may involve an alteration in the intracellular level of cyclic AMP. At least one $\text{in vivo}$ study shows that cyclic AMP protects hair follicles and gut epithelial cells against radiation damage; however, it does not protect lymphosarcoma and breast carcinoma in mice. If a similar phenomenon is found in humans, an elevation of the intracellular level of cyclic AMP during radiation exposure may improve the effectiveness of radiation therapy in those cases where the radiation damage of normal tissue becomes the limiting factor for a continuation of the therapy program. More $\text{in vitro}$ and $\text{in vivo}$ studies on normal and cancer cells are needed to substantiate the role of cyclic nucleotides in radiosensitivity.     

Evidence that opiate receptors mediate suppression of hypertonic saline-induced drinking in the mouse by narcotic antagonists

The effects of naloxone, its $\text{dextro}$-stereisomer, and five other narcotic antagonists were determined on water intake induced by intracellular dehydration in the mouse. The intraperitoneal administration of a 2M sodium chloride solution served as the model for intracellular dehydration. $\text{1}$-Naloxone (0.01-10 mg/kg) reduced drinking in a dose-dependent fashion with an ED₅₀ of 0.55 mg/kg. In contrast, $\text{d}$-naloxone failed to suppress water consumption at doses up to 10 mg/kg. The other narcotic antagonists tested --- naltrexone, diprenorphine, levallorphan, oxilorphan, and nalorphine --- also produced dose-dependent decreases in water consumption. The order of potency of these narcotic antagonists in suppressing water intake was highly correlated with their orders of potency in other procedures involving the opiate receptor. The stereoselectivity and order of potency suggest that the suppressant effects of the narcotic antagonists on drinking induced by hypertonic saline administration in the mouse are mediated through an opiate receptor-dependent mechanism.     

Harmaline distribution in single muscle fibres and the inhibition of sodium efflux

Harmaline, a known inhibitor of the ($\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ in cell membranes, inhibited 50% of the ²²Na efflux from barnacle muscle fibres at an extracellular concentration of 2.4 mM. Injected harmaline inhibited 50% of the efflux at an estimated intracellular concentration of about $\text{8}\text{mM}\text{·}\text{kg}{}^{\mathrm{?1}}$, assuming complete equilibration with no binding. Total fibre harmaline was measured in separate fibres by ultraviolet spectrophotometry. Fibres in 3 mM harmaline saline accumulated harmaline with a half-time of 17 min and a final total fibre concentration of $\text{6–12}\text{mM}\text{·}\text{kg}{}^{\mathrm{?1}}$. In harmaline-free saline this accumulated harmaline was lost exponentially with a half-time of 35 min; injected harmaline was lost exponentially from fibres with a half-time of 50 min. It is proposed that harmaline crosses the fibre membrane as the uncharged base and that its apparent accumulation against a concentration gradient is mainly due to intracellular binding with an additional contribution from a transmembrane pH gradient. It is concluded that, in fibres exposed to harmaline saline, the intracellular concentration can reach a sufficiently high value, as judged from the results of the injection experiments, to inhibit Na⁺ efflux at an interior-facing site on the fibre membrane. In contrast, harmaline appears to inhibit the Na⁺-dependent uptake of l-glutamate at an extracellular site.     

Cytoplasmic factors in the gonads of Culex pipiens complex mosquitoes

Electron microscopic examination of the gonads of six species of the $\text{Culex pipiens}$ complex revealed rickettsia-like, intracellular symbionts in $\text{C.pipiens}$, $\text{C.molestus}$, $\text{C.pallens}$ and $\text{C.fatigans}$.¹ In the two endemic Australian members, $\text{C.a}$$\text{C.globocoxitus}$, no rickettsia-like symbionts were found, but virus-like particles were seen in the cytoplasm of the ovaries and certain associated tissues.     

Host-cell invasion by Trypanosomacruzi: Role of cell surface galactose residues

Alpha-galactosidase treatment of blood, insect and intracellular forms of $\text{T.}\text{cruzi}$ enhanced their ability to associate with mouse peritoneal macrophages or rat heart myoblasts as evidenced by significant increases in both the percentage of infected cells and the number of parasites per cell. The magnitude of the enhancement was greater with invasive (blood and insect) than with noninvasive (intracellular) forms of the parasite. The enzyme effect was reversible, attaining total recovery in 2.5 hr. By contrast, when either host cell was pretreated with the enzyme, the extent of cell-parasite association was significantly reduced. These results indicate that galactose residues on $\text{T.}\text{cruzi}$ and host cells modulate their association in opposite ways.     

Inhibitory effect of unconjugated bilirubin on p-aminohippurate transport in rat kidney cortex slices

(1) The effects of unconjugated bilirubin on the accumulation of $\text{p-}\text{aminohippurate}$, kinetics of $\text{p-}\text{aminohippurate}$ uptake, the efflux of pre-accumulated $\text{p-}\text{aminohippurate}$ and water and electrolyte distribution were investigated in the rat kidney cortical slice. (2) The addition of unconjugated bilirubin to the incubation medium decreased the 60 min slice-to-medium concentration ratio of $\text{p-}\text{aminohippurate}$. (3) The decrease in $\text{p-}\text{aminohippurate}$ accumulation by unconjugated bilirubin was found to be more pronounced by increasing the concentration of pigment in the medium. (4) The rate of uptake of $\text{p-}\text{aminohippurate}$ as a function of $\text{p-}\text{aminohippurate}$ concentration differed in aerobiosis and anaerobiosis, and unconjugated bilirubin decreased only the uptake of $\text{p-}\text{aminohippurate}$ in aerobic conditions. (5) The efflux of pre-accumulated $\text{p-}\text{aminohippurate}$ decreased when unconjugated bilirubin concentration in the medium was low (10–20 μM) but the efflux increased when the concentration of pigment was much higher (100 μM). (6) The addition of unconjugated bilirubin to the medium (40–100 μM) increased intracellular sodium and total tissue water content, and decreased intracellular potassium and oxygen consumption of tissue. However the slices incubated with low concentration of pigment (20 μM) did not exhibit significative changes in cellular functional parameters. (7) These findings suggest that unconjugated bilirubin impairs $\text{p-}\text{aminohippurate}$ transport by a complex mechanism that might involve binding of pigment to sites necessary for anion transport, although effects related to pigment toxicity or to its oxidative decomposition are not excluded.     

The effects of environmental factors on growth and the chemical and biochemical composition of marine diatoms. I. Light and temperature effects

Temperature and light interact to modify the chemical and biochemical composition of a nitrogen-limited marine diatom, Thalassiosira allenii Takano, grown at a constant dilution rate in continuous culture and under a light:dark cycle.The percent of the total ¹⁴C incorporated into protein, polysaccharide and lipid, the N/C ratio and the C/cell varied with temperature in a markedly non-linear manner. The N/cell was negatively correlated to temperature. The Chl $\text{a}\text{C}$ ratio was positively correlated with temperature under saturating light and non-saturating light for temperatures > 25 °C, but was constant under non-saturating light conditions for temperatures < 25 °C.Productivity index (PI) was negatively correlated to temperature under saturating light conditions, but did not vary under low light. In each case, the variation in PI with temperature was governed by the variation in Chl $\text{a}\text{C}$.The dark carbon loss rate was exponentially related to temperature and independent of light. Variation in the percent of the total ¹⁴C incorporated into protein and polysaccharide, the $\text{N}\text{C}$ ratio and C/cell was primarily due to the effects of N-limitation < 20 °C and primarily due to the effects of temperature > 20 °C. Variation in N/cell was primarily due to the effects of temperature over the entire range of temperature studied. Variation in Chl $\text{a}\text{C}$ was caused by the interaction of temperature and light effects.In most cases, temperature and nutrient effects interacted to govern how a particular parameter varied with temperature while light affected the range of values over which the parameter varied.The percent of the total ¹⁴C incorporated into protein exhibited a significant linear relationship with $\text{N}\text{C}$.The dark carbon loss rate, $\text{N}\text{C}$ ratio and Chl $\text{a}\text{C}$ ratio data were used to test the applicability of a model for the physiological adaptation of unicellular algae. The model, with parameters derived from a non-linear least-squares fit of the dark carbon loss rate data, adequately described the $\text{N}\text{C}$ ratio between 15 and 25 °C at 290 and 137 μE · m^?2 · s^?1, but failed to describe the data at 28 °C and at 48 μE · m^?2 · s^?1. The Chl $\text{a}\text{C}$ ratio was adequately described by the model under all light and temperature conditions.