On a Gyrodactylus Species from Northern Sweden and the Subgeneric Position of G. hrabei Ergens, 1957 (Trematoda, Monogenea)

A Gyrodactylus species from northwestern Sweden is described. Because only one specimen of the species was found no specific name is given. The type of protonephridial system of the new species showed that it belongs to the subgenus G. ( Paranephrotus ). Because of the strong resemblance between the new species and G. hrabei Ergens these two species are placed in a new species group: the G. hrabei-group. The Eurasian fresh water fauna seems to have very few representatives belonging to G. ( Paranephrotus ) and because of this the above find is of special interest.     

Effects of cultivation techniques and media on yields and morphology of the basidiomycete Armillaria mellea

Summary The yield of cell mass and the morphology of Armillaria mellea, strain ATCC 11114, was studied using a variety of cultivation methods: solid media, standing liquid culture, shake flasks, tower reactors and impeller-stirred reactors. Two different media, malt extract broth and a glucose/asparagine/peptone-medium, and the corresponding agar media, were used. Yields were higher in the malt extract media than in the glucose media. Generally the highest yields were obtained on solid media while agitated cultures gave the lowest yields. Morphological characteristics such as pellet formation, adhesion to surfaces and pigment production were significantly affected by culture conditions.     

Developmentally regulated antigen associated with calcium crystals in tobacco anthers

We have found and characterized an antigen associated with crystal-containing cells in the stomium and connective tissue of the anthers of Nicotiana tabacum L. (tobacco). The antigen, defined by the monoclonal antibody NtF-8B1, localizes to subcellular regions surrounding the crystals. At the light-microscope level, the antigen is detectable just after the first appearance of crystals in the connective tissue of the anther, and at approximately the same time as the appearance of crystals in the stomium. The antigen is not detectable on a Western blot, and gave inconclusive results on a test of periodate sensitivity. It is not the crystals themselves, nor is the presence of the crystals required for antibody recognition. The antigen is sensitive to heat and protease treatment, indicating that it is a protein. The antigen is not tightly membrane-bound, in spite of its localization closely surrounding the crystals. Chemical tests indicate that the druse crystals in the stomium are calcium oxalate.Abbreviations ELISA enzyme-linked immunosorbent assay - FITC fluorescein isothiocyanate This research was supported by a National Science Foundation postdoctoral fellowship to B.L.H., by National Science Foundation grants DMB-87-15799 and to W.E.F. BSR-88-18035, and by U.S. Department of Agriculture grant GAM-89-01056. The authors thank Phillip T. Evans (Louisiana State University, Baton Rouge, USA), Wilma L. Lingle, Harry T. Horner, Jr. (Iowa State University), and A. Jack Fowler, Jr., for advice and helpful discussions.     

High prevalence of asthma in cross country skiers.

OBJECTIVES--To study the prevalence of asthma (asthma symptoms and bronchial hyperresponsiveness) in Swedish cross country skiers compared with non-skiers and monitor changes in symptoms and bronchial hyperresponsiveness during the year. DESIGN--Cross sectional study during the winter ski season and in the summer. SETTING--Six ski clubs for élite skiers (total 47) in two different areas of Sweden. SUBJECTS--42 élite cross country skiers and 29 non-skiing referents. MAIN OUTCOME MEASURES--Bronchial responsiveness, asthma symptoms, and lung function. RESULTS--Bronchial responsiveness was significantly greater and asthma symptoms more prevalent in the skiers than in the referents. There was no difference in bronchial responsiveness within either group between winter and summer. 15 of the 42 skiers used antiasthmatic drugs regularly and 23 had a combination of asthma symptoms and hyperresponsive airways or physician diagnosed asthma, or both. Altogether 33 skiers had symptoms of asthma or bronchial hyperresponsiveness. One of the referents had symptoms of asthma and bronchial hyperresponsiveness, and none used antiasthmatic drugs regularly. CONCLUSIONS--Asthma, asthma-like symptoms, and bronchial hyperresponsiveness are much more common in cross country skiers than in the general population and non-skiers. Strenuous exercise at low temperatures entailing breathing large volumes of cold air is the most probable explanation of persistent asthma in skiers.     

Effects of Prostaglandin E2 and Capsaicin on Behavior and Cerebrospinal Fluid Amino Acid Concentrations of Unanesthetized Rats: A Microdialysis Study

Abstract: Prostaglandin E₂ (PGE₂) delivered to the spinal cord produces an increased sensitivity to noxious (hyperalgesia) and innocuous (allodynia) stimuli. The mechanisms that underlie this effect remain unknown, but a PGE₂-evoked enhancement of spinal neurotransmitter release may be involved. To address this hypothesis, we examined the effect of PGE₂ on CSF concentrations of amino acids and also the modulatory effect of PGE₂ on capsaicin-evoked changes of spinal amino acid concentrations using a microdialysis probe placed in the lumbar subarachnoid space. Amino acids were quantified using HPLC with fluorescence detection. Addition of 1 mM, but not 10 or 100 µM, PGE₂ to the perfusate for a 10-min period (flow rate, 5 µl/min) evoked an immediate increase (80–100%) in glutamate (Glu), aspartate (Asp), taurine (Tau), glycine (Gly), and γ-aminobutyric acid (GABA) concentrations. Similarly, capsaicin infusion (0.1–10 µM) induced a dose-dependent increase in Glu, Asp, Tau, Gly, GABA, and ethanolamine levels. Significant increases in amino acid levels evoked by PGE₂ or capsaicin were associated with a touch-evoked allodynia. The combination of PGE₂ (10 µM) and capsaicin (0.1 or 1.0 µM) at concentrations that individually had no effect together evoked a significant increase (60–100%) in Glu, Asp, Tau, Gly, and GABA concentrations and produced tactile allodynia. These data demonstrate that spinally delivered PGE₂ or capsaicin substantially elevates CSF concentrations of both excitatory and inhibitory amino acids. The capacity of PGE₂ to enhance and prolong capsaicin-evoked amino acid concentrations may be one of the mechanisms by which spinal PGE₂ produces hyperalgesia and allodynia.     

Regeneration of whole plants from callus culture of diverse genetic lines of Pisum sativum L.

Sixteen genetic lines of peas were screened for their ability to regenerate whole plants from callus cultures. Epicotyl sections from germinating seeds were placed on callus-inducing medium; the resulting callus was subcultured monthly and was tested every other month for its regeneration ability. Six lines were found that would regenerate after 2 months' growth as callus. Four of these continued to regenerate after 4 months and, of these, two after 6 months. The cultivars Frosty and Alaska were among the lines that would not regenerate at all.Michigan Agricultural Experiment Station Journal Article No. 8932     

Variability of measurements of cranial growth in the rabbit

This study concerns techniques used in experimental cranial growth research: roentgen cephalometry, roentgen stereophotogrammetry, and gross measurements (osteometry). A comparison of the precision of these methods has not been found in the literature. Computation of technical errors is fundamental to the sound evaluation of registered findings, and such a presentation must be obligatory in all biometric reports. We compared the measurement error of roentgen cephalometric and osteometric data with that obtained by roentgen stereophotogrammetry (RSA). RSA demonstrates a superior replicability, and this technique gives possibilities for kinematic and volumetric determinations simultaneously with distance evaluation. Roentgen cephalometry has the advantage of enabling distance and angular measurements between any well-defined skeletal points or lines. This technique, preferably after implantation of bone markers, is a reliable alternative, but optimal results necessitates calculations of the magnification factor for each bone segment involved. Direct osteometry does not contribute additional information, but problems of image magnification are omitted. Preferably, one individual should perform all measurements regardless of the method used. Growth rates and values calculated by one technique cannot be directly transformed to some other approach. In all probability, assessments of distance changes would gain substantially by using one technical approach consistently throughout actual age intervals. The least variable measurements of sutural growth are made for sutures growing primarily in one plane and with substantial growth rates. One must realize that differences among studies may be due to the limitations of, in particular, the cephalometric and osteometric techniques.     

Solubilization and spectral characteristics of chlorophyll-protein complexes isolated from the thermophilic blue-green alga Synechococcus lividus

The thermophilic blue-green alga Synechococcus lividus was grown at 38 and 55°C. The reaction center chlorophyll-protein complexes (CP) of Photosystem (PS I) and PS II, CP a_I and CP a_II, were isolated by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis at 4°C. SDS solubilization of thylakoids was performed in the temperature range 0–65°C. The low-temperature absorption and fluorescence emission spectral properties of the isolated chlorophyll-protein complexes were analyzed. Only traces of CP a_I were solubilized at temperatures below the lipid phase transition temperature. Instead, a minor PS I component, CP a′_I, was obtained that had absorption and fluorescence characteristics similar to those of CP a_I. CP a′_I had a slightly lower mobility than CP a_I in SDS-polyacrylamide gel electrophoresis. The amount of CP a_I in the gel scan profile increased dramatically when solubilization was carried out above the phase transition temperatures, but started to decrease above 60°C. CP a_II, on the other hand, could be efficiently extracted even at 0°C and was stable in the scan profile up to extraction temperatures of 30–40°C. Low-temperature absorption and fluorescence emission spectra were typical for CP a_I and CP a_II and no specific effects of the two growth temperatures on these properties were observed. The phase transition temperature was considered to be critical for the solubilization of CP a_I, either because of the difficulties of SDS (especially as it forms micelles at low temperatures) in penetrating the solidified membrane lipids at temperatures below that of the phase transition or because the CP a_I monomers of the PS I antennae are so strongly bound to each other that they cannot be dissociated by SDS before thermal agitation has reached a certain level that is achieved above the phase transition temperature. We consider both the difficulties in solubilizing CP a_I at sub-transition temperatures and the heat stability of the two complexes as adaptations which enable Synechococcus to grow under extreme high-temperature regimes.     

NOTE—THE STA-1 MUTATION PREVENTS ASSEMBLY OF STARCH GRANULES IN NITROGEN-STARVED CELLS AND SERVES AS A USEFUL MORPHOLOGICAL MARKER DURING SEXUAL REPRODUCTION IN CHLAMYDOMONAS MONOICA (CHLOROPHYCEAE)

Iodine staining of clones of nitrogen-starved Chlamydomonas cells was used to screen for mutants with altered levels or altered composition of storage starch. Mutations leading to defects in quantity or morphology of starch granules not only can provide information on storage starch biosynthesis and granule assembly but can also be used as morphological markers in genetic and cell biological studies. A mutant of Chlamydomonas monoica Strehlow devoid of starch granules was obtained following ultraviolet mutagenesis. Nitrogen-starved cells of the sta-1 strain lacked pyrenoidal starch granules and granules normally associated with thylakoid membranes. The mutant phenotype was the consequence of a single Mendelian mutation that appeared to affect granule assembly rather than starch biosynthesis per se and that had no effect on vegetative growth, sexual reproduction, or zygospore viability.