Bovine fetal anoxia observed in pregnant beef heifers experimentally inoculated with Anaplasma marginale

Six heifers in the third trimester of gestation were inoculated with Anaplasma marginale carrier blood. Laparohysterotomies were performed under local anesthesia at varying stages of anemia induced by anaplasmosis and the placental blood gas exchange was examined. Laparohysterotomies were similarly performed on three uninoculated control heifers and the placental blood gas exchange compared to the fetuses recovered from anemic (inoculated) heifers. Blood samples from the dam and fetus were recovered at the time of surgery and arterial blood gases and pH determined. A decline in fetal oxygen tension accompanied the maternal anemia. The evidence suggests that third trimester fetal death in heifers experimentally inoculated with Anaplasma marginale is due to fetal anoxia.     

Influence of increased membrane cholesterol on membrane fluidity and cell function in human red blood cells

Cholesterol and phospholipid are the two major lipids of the red cell membrane. Cholesterol is insoluble in water but is solubilized by phospholipids both in membranes and in plasma lipoproteins. Morever, cholesterol exchanges between membranes and lipoproteins. An equilibrium partition is established based on the amount of cholesterol relative to phospholipid (C/PL) in these two compartments. Increases in the C/PL of red cell membranes have been studied under three conditions: First, spontaneous increases in vivo have been observed in the spur red cells of patients with severe liver disease; second, similar red cell changes in vivo have been induced by the administration of cholesterol-enriched diets to rodents and dogs; third, increases in membrane cholesterol have been induced in vitro by enriching the C/PL of the lipoprotein environment with cholesterol-phospholipid dispersions (liposomes) having a C/PL of >1.0. In each case, there is a close relationship between the C/PL of the plasma environment and the C/PL of the red cell membrane. In vivo, the C/PL mole ratio of red cell membranes ranges from a normal value of 0.9–1.0 to values which approach but do not reach 2.0. In vitro, this ratio approaches 3.0. Cholesterol enrichment of red cell membranes directly influences membrane lipid fluidity, as assessed by the rotational diffusion of hydrophobic fluorescent probes such as diphenyl hexatriene (DPH). A close correlation exists between increases in red cell membrane C/PL and decreases in membrane fluidity over the range of membrane C/PL from 1.0 to 2.0; however, little further change in fluidity occurs when membrane C/PL is increased to 2.0–3.0. Cholesterol enrichment of red cell membranes is associated with the transformation of cell contour to one which is redundant and folded, and this is associated with a decrease in red cell filterability in vitro. Circulation in vivo in the presence of the slpeen further modifies cell shape to a spiny, irregular (spur) form, and the survival of cholesterol-rich red cells is decreased in the presence of the spleen. Although active Na-K transport is not influenced by cholesterol enrichment of human red cells, several carrier-mediated transport pathways are inhibited. We have demonstrated this effect for the cotransport of Na + K and similar results have been obtained by others in studies of organic acid transport and the transport of small neutral molecules such as erythritol and glycerol. Thus, red cell membrane C/PL is sensitive to the C/PL of the plasma environment. Increasing membrane C/PL causes a decrease in membrane fluidity, and these changes are associated with a reduction in membrane permeability, a distortion of cell contour and filterability and a shortening of the survival of redcells in vivo.     

Adenosine 3′:5′-cyclic phosphate-dependent and -independent protein kinases of renal brush border membranes: Solubilization,separation, and characterization of multiple forms

Multiple protein kinase activities were found in the luminal segment of the renal proximal tubule cell plasma membrane (brush border membrane). Membranes were extracted with Lubrol, with no loss in activity, and the extract was chromatographed on diethylaminoethyl cellulose with a salt gradient. With protamine as substrate, activity eluted in two peaks, designated I and IIb, and was cyclic AMP independent. With histone VII-S, one peak, designated IIa, appeared, which eluted slightly ahead of IIb and was cyclic AMP dependent. The three activities eluted in their original patterns following rechromatography. Histone kinase activity in the combined IIa+b fraction was stimulated threefold by cyclic nucleotides (K_a = 0.013 and 0.94 μM for cyclic AMP and cyclic GMP, respectively) by increasing V. Cyclic AMP binding activity eluted with histone kinase activity. Rechromatography of IIa+b on diethylaminoethyl cellulose containing 1 μm cyclic AMP resulted in passage through the column of most of the histone kinase activity (IIa) prior to the salt gradient, but retention of kinase IIb, which again eluted in its original position. Characterization of the separated enzymes revealed that kinase I was highly specific for protamine and totally insensitive to cyclic AMP and a specific protein inhibitor of cyclic AMP-dependent kinases. Kinase IIa was relatively specific for histones and was completely inhibited by the protein inhibitor. Kinase IIb was nonspecific, catalyzing phosphorylation of protamine, casein, histones, and phosvitin in decreasing order of activity, and was insensitive to cyclic AMP and the protein inhibitor. Exposure of intact brush border membranes to elevated temperatures revealed that phosphorylation of intrinsic membrane proteins and protamine was thermolabile, whereas cyclic AMP-dependent histone kinase activity was relatively thermostable. These findings implicate cyclic AMP-independent protamine kinases in the cyclic AMP-independent autophosphorylation of the brush border membrane.     

Acid mine drainage treatment with rotating biological contactors

A pilot scale rotating biological contactor (RBC) was set up near a coal mine at Hollywood, Penn. to evaluate ferrous iron, Fe(II), oxidation. Acid drainage from this mine entered the treatment unit which consisted of four sets of plastic disks affixed to a rotating central shaft. As the disks rotated half immersed in the flowing mine water, iron-oxidizing bacteria, presumed to be Thiobacillus ferrooxidans, colonized the disk surfaces with an average population of 70,000 cells/cm² and mediated the transformation of Fe(II) to the less soluble ferric state, Fe(III). Kinetics of microbial Fe(II) oxidation were established during an eleven month period of continuous pilot operation and were found to follow a concentration dependent first order relationship. Operating at an optimum disk rotation rate and hydraulic loadings of 2.7 and 5.4 gal/day-ft² (0.11 and 0.22 m³/day-m²) resulted in the oxidation of an average 240 mg/liter influent Fe(II) to produce effluent Fe(II) of 2 and mg/liter, respectively. The RBC appears potentially useful as a first step in the total treatment of acid mine drainage.     

Glucose tolerance factor: an essential dietary agent

Glucose tolerance factor (GTF), the biologically active form of chromium, is an essential dietary agent that potentiates the action of insulin and thereby functions in regulating carbohydrate metabolism. Dietary trends that show increased consumption of more highly processed foods may be leading to deficiencies of'GTF and chromium in man.     

Critical adjustment of cysteine and glutamine concentrations for improved clonal growth of WI-38 cells

Summary Clonal growth of WI-38 cells with a plating efficiency of 45% has been achieved in a synthetic nutrient mixture (MCDB 102) supplemented with either whole or dialyzed fetal bovine serum. For optimum growth, the concentration of cysteine in the medium must be adjusted precisely. Deviation by a factor of three in either direction from the optimum concentration (9.0×10⁻⁵M) eliminates essentially all clonal growth. A high concentration of glutamine (2.5×10⁻³M) is also needed for, optimum clonal growth. Presented in preliminary form at the 26th Annual Meeting of the Tissue Culture Association, June 4, 1975. This work was supported by Grant No. HD-08181 from the National Institute of Child Health and Human Developement, Grant No. AG-00310 from the National Institute on Aging, and by Contract No. 223-74-1156 from the Bureau of Biologics, Food and Drug Administration.     

Role of calcium in the initiation of fast axonal transport of protein: Effects of divalent cations

Fast axonal transport of [³H]protein has been examined in bullfrog primary afferent neurons incubated in media supplemented with divalent cations that can act as agonists or antagonists of calcium ions. Incubation in calcium-free medium (CFM) had no effect on the rate of transport, but reduced the amount of transported [³H]protein by 40–60% relative to transport in the contralateral preparation maintained in normal medium. Preparations incubated in CFM supplemented with 1.8 mM SrCl₂ (equimolar to the CaCl₂ concentration in normal medium) carried out transport at control levels. Incubation conditions in which primary afferent somata were exposed to the Sr²⁺-medium while nerve trunks were maintained in CFM also supported normal transport. By contrast, selective exposure of nerve trunks to Sr²⁺-medium, and somata to CFM resulted in a reduced level of transport similar to that observed when the whole preparation was incubated in CFM. The depression of transport resulting from incubation in CFM was shown to be reversible when preparations were transferred from CFM to either Sr²⁺-supplemented CFM or to normal medium. By contrast to the effects of Sr²⁺, Ba²⁺ (up to 18 mM) did not substitute for Ca²⁺ in the transport process. When normal medium was supplemented with calciumantagonist cations, the amount of transport was depressed (Co²⁺ > Mn²⁺ >> Mg²⁺), with no concomitant effect on the rate of transport. Results of studies with Co²⁺, as well as those with Sr²⁺, suggest that a major locus of action of these cations is within the neuronal soma at a step subsequent to protein synthesis, and prior to the onset of protein translocation via the transport system. Thus, it is inferred that these divalent cations affect a calcium-dependent step that occurs during the initiation phase of fast axonal transport.     

Legionella pneumophila cell envelope: Permeability to hydrophobic molecules

Legionella pneumophila is sensitive to a number of toxic hydrophobic compounds. Suspensions of cells bound large amounts of the dye crystal violet, and disk agar diffusion assays confirmed the marked sensitivity to this compound. Fatty acids were also inhibitory to the growth ofL. pneumophila in liquid media, and growth inhibition increased with increasing chain length to a maximum with myristic acid. Oxygen uptake by respiring cells was inhibited by similar concentrations of fatty acids.L. pneumophila was also sensitive to low concentrations of progesterone. These results indicated thatL. pneumophila has an outer membrane with unusual permeability to hydrophobic compounds. This characteristic was accompanied by a measurable cell surface hydrophobicity as determined by adherence of the bacterium to the hydrocarbon hexadecane.