Listeriosis in Sheep

A comparison was made between a hay fed group, consisting of 23 ewes, and a grass silage fed group of 22 ewes, all pregnant. Excretion of Listeria monocytogenes (Lm) in the faeces and milk, antibody titres in sera and whey and delayed hypersensitivity against Lm, and several blood components were determined. The animals had previously been exposed to Lm, and Lm was isolated from the faeces from several animals when the experiment started. No significant difference in number of excretors between the 2 groups was found during the experimental period. The haemagglutination titres in both sera and whey were low and on the same level in both groups. The titres were higher in animals with 1 foetus than in animals with more than 1 foetus. In the first part of the experimental period the silage group had a reduced number of lymphocytes, lower total serum protein values and higher serum iron values, compared with the hay group. The silage group also had a stronger delayed hypersensitivity reaction against Lm than the hay group, and in the silage group the reaction was significantly stronger in ewes with 3 or more foetuses than in ewes with 1 foetus. In conclusion, the combined effect of some of the changes found in animals fed grass silage may leave them more susceptible to infections.     

Isolation of the porcine ileal intrinsic factor receptor by sequential affinity chromatography

An extract containing solubilised receptor was passed through four columns containing Sepharose to which had been covalently coupled anti-cobalophilin IgG, vitamin B-12-intrinsic factor, vitamin B-12, and free intrinsic factor, respectively. Following a wash the receptor was eluted with EDTA, then residual Triton X-100 micelles and vitamin B-12-intrinsic factor were removed by Sephadex G-200 filtration. The receptor was purified 84 000-fold, sodium dodecyl sulphate electrophoresis indicated two subunits and gel filtration of its vitamin B-12-inttrinsic factor complex resolved it into two molecular species.     

Arterial hypoxia does not affect subchondral pressure and regional blood flow

The influence of arterial hypoxia on bone marrow pressure, regional blood flow and oxygen and carbon dioxide tensions was investigated by simultaneous and continuous measurements in the femoral condyles of 8 rabbits. Arterial hypoxia was obtained by hypoventilation. The subchondral gas tensions and regional blood flow were measured by a previously described technique based on mass spectrometry. Arterial hypoxia caused a significant decrease in subchondral oxygen tension and an increase in subchondral carbon dioxide tension. There was no significant change in bone marrow pressure and regional blood flow.     

Macromolecules in the receptor lymph of campaniform sensilla

Summary The receptor lymph of campaniform sensilla on the halteres of the blowfly, Calliphora vicina, was analyzed histochemically. Acid mucopolysaccharides were demonstrated by a test for iron-binding capacity (Hale-reaction). Further characterization by enzyme treatment showed that the receptor lymph contains hyaluronic acid and/or chondroitin sulfate. Ultrahistochemical studies gave evidence for glycoproteins in the inner and outer receptor lymph space. The significance of acid mucopolysaccharides for arthropod sensilla is discussed.     

Aestival dormancy in the cabbage moth Mamestra brassicae L. (Lepidoptera: Noctuidae)

Summary In a geographically wide distribution the life cycles of different populations of the cabbage moth Mamestra brossicae are adapted to a remarkable diversity of climatic conditions. This is undoubtedly a proof of its success in adaptation. Some populations living in regions characterized by a drought period interrupting the growth season are capable of distinguishing between one critical day length signalling the onset of the drought period and another signalling the end of the growth season. This study, therefore, is primarily concerned with the geographical patterns in the variability of the adaptional responses of populations exposed to environmental conditions requiring different strategies and tactics in, synchronizing individual, life cycles. It is also a contribution to our understanding of evolutionary mechanisms maintaining median responses to photoperiodically inductive day lengths in geographically different populations. The populations investigated originated from regions differing in predictability of the incidence, onset and duration of a drought period: Freiburg (48.0°N, Southern Germany), Avignon (44.0°N, Southern France), and Argelès (42.5°N, Southern France). Geographical variation with respect to both onset and duration of a drought period consequently results in clinal variation of the variability of innate day length thresholds triggering aestival dormancy and of innate duration of aestivation. In this paper we considered the influence of geographically changing temperatures on aestival dormancy induction. Even in southern populations of M. brassicae a temperature dependent switch off-mechanism exists which prevents aestival dormancy under certain environmental conditions. The effective temperatures vary geographically, too. What the geographical patterns in adaptive responses really are, is discussed.This research was supported by the Deutsche Forschungsgemeinschaft (Sa 259/3-1)     

An immunological approach to enrich a mitotic stimulator and to reveal G2-phase-specific proteins in Physarum polycephalum

Purified antibodies from an antiserum against S-phase proteins of the myxomycete Physarum polycephalum were attached to protein-A-Sepharose CL-4B. A late G2-phase extract that contained a mitosis-stimulating protein was applied to this immunoadsorbent, and the mitosis-stimulating protein was enriched by a factor of ten. This protein, which is present in the cell in low amounts, is synthesized in late G2 phase and obviously degraded in a later stage of the cycle. Immunoadsorption of a G2-phase extract with anti-S-antibodies decreased the 700 main proteins to 20 as demonstrated by two-dimensional gel electrophoresis. No difference in protein pattern could be observed on two-dimensional gels between S-phase and G2-phase extracts before and after immunoadsorption with anti-S-antibodies. This indicates that there are no G2-phase-specific proteins among the 700 most abundant proteins of Physarum polycephalum.     

Pleiotropic effects of a butyrolactone-type autoregulator on mutants of Streptomyces griseus blocked in cytodifferentiation

Mutants of Streptomyces griseus blocked in cytodifferentiation regained their capacity to form differentiated mycelia and/or anthracycline pigments in the presence of butyrolactone-type autoregulatory effectors such as trans-2-(6'-methylheptanol-1'-yl)-3-hydroxymethyl-4-butanolide+ ++. In the pertinent indicator strains, the effect has been correlated with the increase of lipid synthesis, with changes in the composition of lipid fraction and with the restoration of the production of neutral proteinases. The results suggest that autoregulatory butyrolactones from streptomycetes stimulate cytodifferentiation of their producers at an early stage of development.     

Improved demonstration of exocytotic profiles in glomus cells of rat carotid body after perfusion with glutaraldehyde fixative containing a high concentration of potassium

Extensive secretion by exocytosis was demonstrated in the glomus (type I) cells of the adult rat after perfusion of carotid bodies with a potassium-rich (high K) glutaraldehyde fixative. Similar secretory profiles were very rare with a glutaraldehyde fixative containing a low concentration of potassium (low K). The increase in the incidence of exocytotic profiles in glomus cells with the high K fixative was highly significant, whereas no statistical difference could be observed in the incidence of coated pits with the different fixatives. Exocytotic profiles were characterized by the following features: (1) they predominated in non-synaptic regions, but were occasionally observed near synapses between two glomus cells; they were not observed near synapses between glomus cells and nerve terminals; (2) extruded electron-dense material associated with coating of the cell membrane was frequent; (3) different stages of dissolution of the extruded granule material was evident. The possible role of exocytosis as a mode of secretion in the glomus cells and the characteristics of the new high K-glutaraldehyde fixative are discussed.