Isolation of Actinobacillus suis from a Canada goose (Branta canadensis)

Blindness from conjunctivitis caused by Actinobacillus suis was found in a Canada goose (Branta canadensis) from a wildlife refuge in Kentucky. Lesions were not observed elsewhere and other body organs were grossly normal. Actinobacillus spp. in birds is rare and this is apparently the first report of conjunctivitis resulting from this infection in waterfowl.     

Beta-adrenergic agonists and cyclic AMP decrease intracellular resting free-calcium concentration in ileum smooth muscle

Intracellular free-calcium levels were measured in strips of longitudinal smooth muscle from guinea-pig ileum; fura-2 was used as a calcium monitor. At rest the calcium concentration was about 180 nM, and this rose to 300-400 nM following electrical stimulation and during spontaneous calcium transients (all measurements at 23-25 degrees C). Isoprenaline suppressed the spontaneous calcium transients, and reduced the resting calcium level to about 130 nM. This fall in resting calcium concentration was seen even in muscle strips which did not have spontaneous activity. Elevation of intracellular cyclic AMP levels, produced by forskolin or dibutyryl cyclic AMP, mimicked the actions of isoprenaline. We conclude that the relaxant effects of beta-adrenergic agonists of visceral smooth muscle may be explained partly by a fall in intracellular resting free-calcium level, mediated via an increase in cyclic AMP.     

Critical considerations in the development of an assay for sulfidopeptide leukotrienes in plasma

A sensitive and specific assay has been developed for measurement of total sulfidopeptide leukotrienes (LT) in plasma. LTC4 and LTD4 in plasma are converted to LTE4 which is then extracted by C18 Sep-Pak binding and elution. Total LTE4 is resolved by reverse phase high performance liquid chromatography (RP-HPLC) and quantitated by radioimmunoassay (RIA). A [3H]LTE4 internal standard is added to the starting plasma sample to allow overall recovery to be calculated and to define the fractions from RP-HPLC to be assayed for LTE4-like immunoreactivity. The correlation between the measured increase in LTE4 concentration after addition of incremental amounts of LTC4 and LTE4 to plasma was 0.989 and 0.978, respectively, with slopes of 1.05 and 1.11. Addition of 51 pg/ml LTE4 to 5 ml plasma was detectable; the measured increase was 48 +/- 12 pg/ml (mean +/- SE, n = 7). The intra-assay coefficient of variation for 341 pg/ml of added LTC4 was 3.2% (n = 6). Sulfidopeptide leukotrienes could not be detected in blood samples taken from 12 normal volunteers in whom the theoretical detection limit, calculated from the sensitivity of the RIA, the overall recovery of LTE4, and the volume of plasma extracted, was 83 +/- 4 pg LTE4/ml plasma (0.19 +/- 0.01 pmol sulfidopeptide leukotriene/ml plasma; mean +/- SE).     

Evaluation of the single radial-immunodiffusion assay for measuring the glycoprotein content of rabies vaccines

The glycoprotein content of rabies vaccines containing the Pitman-Moore strain of rabies virus was measured by the single radial immunodiffusion assay and correlated with vaccine potency. The variability of this assay was 6.3% for a single vaccine lot tested over a one-year period. Using sera prepared against rabies virus glycoprotein from different strains of virus, the assay gave different values. These differences could be eliminated by using a homologous vaccine strain as an internal reference. Single radial-immunodiffusion values for Pitman-Moore vaccines correlated with the manufacturers' NIH potency assay, but required a mathematical transformation to convert values from one assay to the other. Single radial-immunodiffusion values for Street Alabama Dufferin and Flury-LEP vaccines did not correlate with NIH values. Modification of the single radial immunodiffusion technique and the feasibility of using this assay for the determination of rabies vaccine potency are discussed.     

Short-term movements of chalk-stream invertebrates

SUMMARY 1. Trays of gravel were implanted for 24 h periods in several chalk streams. The trays were variously modified to monitor colonization from different sources, particularly drift (D), other downstream movements (DSM), upstream movements (USM), and all sources combined (ALL).
2. The abundance of invertebrates in the streams was high (maximum of 717 per 0.04 m²) and colonization of the trays was extensive, especially by Gammarus pulex , the predominant species in all but one of the streams (maximum number of individuals of G. pulex per tray: for D, 473; for DSM, 462; tor USM, 286; and tor ALL, 639). In some cases benthic densities were achieved in the trays in the 24 h exposure period, and in most cases any one source of colonization could provide benthic densities in a few days.
3. Patterns of movement differed between species, between size classes of G. pulex , and between sites for particular species. No one source of colonization could be regarded as generally predominant although downstream movements in total (D + DSM) usually far exceeded USM. DSM was usually an important source of colonization.
4. The extent and direction of movement appeared to be determined by local factors and were explained in terms of the high densities of invertebrates and the current and substratum characteristics of each site.
5. Estimates of the relative importance of different sources of colonization varied greatly according to the criteria used in determining proportions.     

Additional characteristics of one-carbon-compound utilization by Eubacterium limosum and Acetobacterium woodii

Growth characteristics of Eubacterium limosum and Acetobacterium woodii during one-carbon-compound utilization were investigated. E. limosum RF grew with formate as the sole energy source. Formate also replaced a requirement for CO2 during growth with methanol. Growth with methanol required either rumen fluid, yeast extract, or acetate, but their effects were not additive. Cultures were adapted to grow in concentrations of methanol of up to 494 mM. Growth occurred with methanol in the presence of elevated levels of Na+ (576 mM). The pH optima for growth with methanol, H2-CO2, and carbon monoxide were similar (7.0 to 7.2). Growth occurred with glucose at a pH of 4.7, but not at 4.0. The apparent Km values for methanol and hydrogen were 2.7 and 0.34 mM, respectively. The apparent Vmax values for methanol and hydrogen were 1.7 and 0.11 mumol/mg of protein X min-1, respectively. The Ks value for CO was estimated to be less than 75 microM. Cellular growth yields were 70.5, 7.1, 3.38, and 0.84 g (dry weight) per mol utilized for glucose, methanol, CO, and hydrogen (in H2-CO2), respectively. E. limosum was also able to grow with methoxylated aromatic compounds as energy sources. Glucose apparently repressed the ability of E. limosum to use methanol, hydrogen, or isoleucine but not CO. Growth with mixtures of methanol, H2, CO, or isoleucine was not diauxic. The results, especially the relatively high apparent Km values for H2 and methanol, may indicate why E. limosum does not usually compete with rumen methanogens for these energy sources.(ABSTRACT TRUNCATED AT 250 WORDS)     

A new species of Bradyidius (Copepoda, Calanoida) from the Gulf of Carpentaria, Australia

A new species of copepod belonging to the family Aetideidae,Bradyidius slyliformis sp. nov. is described and figured. Therelationship of this species to the other 12 members of thegenus is discussed. ¹Present address: 121 Jalan Athinahapan Dua, Taman Tun Dr Ismail,60000 Kuala Lumpur, Malaysia     

Effect of high concentration of nutrients onBacillus thuringiensis cultures

Summary Bacterial insecticide production using a strain ofBacillus thuringiensis var. kurstaki was studied in batch culture considering the influence of increasing concentration of components of a glucose — yeast extract — mineral salts medium.It was found that spore counts were increased from 1.08×10¹² spores. 1^–1 to 7.36×10¹² spores. 1^–1 and toxin level from 1.05 mg.ml^–1 to 6.85 mg.ml^–1, when the concentration of glucose was increased from 8 to 56 (g 1^–1), with the corresponding increase in the rest of medium components. Higher concentration of nutrients inhibit either spore count or toxin production.Preliminary experiments of fed-batch cultures which allows the use of high amounts of nutrients were also carried out. In this case spore counts of 1.2×10¹³ spores.1^–1 were achieved.     

Pheophytin-mediated energy storage of photosystem II particles detected by photoacoustic spectroscopy

The photoacoustic (PA) characteristics (energy storage and heat dissipation) of photosystem II (PSII) core-enriched particles from barley were studied (i) in conditions where there was electron flow, i.e., in the presence of a combination of the electron acceptor K₃ Fe (CN)₆, referred to as FeCN, and the electron donor diphenylcarbazide (DPC), and (ii) in conditions where electron flow was suppressed, i.e., in the absence of FeCN and DPC. The experimental data show that a decrease of heat dissipation with a minimum at 540 nm can be interpreted as energy storage resulting from the presence of pheophytin (Pheo) in the PSII particles. On account of the capability of the PA method to measure the energy absorbed by the chromophores which is converted to heat, it is suggested that the PA detection of Pheo present in the PSII complex will permit to clarify the function of processes involving non-radiative relaxation of excited states in P680-Pheo-Q_A interactions.Abbreviations -Car -Carotene - Chl Chlorophyll - DPC Diphenylcarbazide - EPR Electron Paramagnetic Resonance - FeCN potassium ferricyanide - HEPES N-2-hydroxyethylenepiperazine-N-2-ethanesulfonate - P680 reaction center of PSII - PA Photoacoustic - Pheo pheophytin - PSI photosystem I - PSII photosystem II - Q_A primary electron acceptor of PSII