The use of a multipoint inoculation method to perform lysostaphin, lysozyme and glycerol-erythromycin tests for the differentiation of staphylococci and micrococci

A multipoint inoculation procedure for performing lysostaphin, lysozyme and glycerol-erythromycin tests for the separation of staphylococci from micrococci is described. The method enabled the tests to be carried out more rapidly and conveniently than with conventional methods.     

Amiodarone and its putative metabolites fail to activate wild type hTAAR1

The ability of amiodarone and its putative metabolites to activate unmodified human trace amine associated receptor 1 (hTAAR1) stably expressed in CHO cell lines was evaluated. Receptor activation was monitored by measuring the accumulation of cAMP, the putative hTAAR1 native second messenger, or calcium mobilization in cells where the receptor was coupled to the promiscuous Gq, G_α16. Despite literature reports of activation of rodent TAAR1 by these agents, no response was seen in either cell line although robust activation was obtained with the endogenous ligand β-phenethylamine. These results indicate that TAAR1 activation by amiodarone and its analogs is species specific.     

Sheep antibody response to cell wall antigens expressed in vivo by Pasteurella haemolytica serotype A2

Abstract Cells of Pasteurella haemolytica A2 were harvested directly from the pleural fluid of sheep with pneumonic pasteurellosis and the protein composition of their envelopes was examined by SDS-PAGE. Several high molecular-weight proteins expressed in pleural fluid were absent when the same isolate was grown in nutrient broth, but were produced during culture in iron restricted media. When the cell wall envelopes were examined by immunoblotting with sera and lung washes of lambs recovering from pneumonic pasteurellosis, antibodies to the major outer membrane proteins, the iron-regulated proteins and one other 'in vivo'-expressed antigen were present. These results have implications for the formulation of effective vaccines against pasteurellosis in sheep.     

Genetic interaction between Non-MHC T- and B-cell alloantigens in response to rous sarcomas in chickens

Chickens of Regional Poultry Research Laboratory (RPRL) inbred line 6₃ regress sarcomas induced by Bryan high-titer Rous sarcoma virus to a greater extent than chickens of line RPRL 100, although these lines are identical for the major histocompatibility B complex. They differ, however, at three independent autosomal loci: Ly-4 and Th-1 determine the surface alloantigens of partly overlapping subsets of T lymphocytes, and Bu-1 determines a surface alloantigen of B lymphocytes. The association of genotypes at these loci with quantitative variation in their ability to regress Rous sarcomas was tested in segregating F₄ generation progeny derived from crosses of lines 100 and 6₃. The Ly-4 and Bu-1 genotypes showed association with Rous sarcoma regression, but the Th-1 genotype did not. Chickens of the Ly-4 ^a/Ly-4 ^a, Bu-1 ^b/Bu-1 ^b and Ly-4 ^b/Ly-4 ^b, Bu-1 ^a/Bu-1 ^a genotypes had a significantly higher regressor ability than the other two double homozygous genotypes. These results indicate that higher regression is associated with (1) interaction between the Ly-4 and Bu-1 loci, and (2) complementation between either the line 6 Ly-4 ^a allele and the line 100 Bu-1 ^b allele, or the line 100 Ly-4 ^b allele and the line 6 Bu-1 ^a allele.     

Stress from air emersion fails to alter chloride cell numbers in the gills of rainbow trout

Air emersion stress caused an elevation in blood plasma cortisol of rainbow trout Oncorhynchus mykiss but this acute stressor did not elicit chloride cell proliferation in the gill tissue within 2 weeks following the disturbance.     

Physiological response of the unicellular green alga Chlorococcum submarinum to rapid changes in salinity

Cell volumes and intracellular concentrations of major solutes of Chlorococcum submarinum were determined before and after salinity shocks. Cells were found to shrink in size by about 30% following changes from 0.1 to 0.5 M NaCl, there was a transitory increase in sodium concentration and more permanent increases in concentrations of potassium, proline and glycerol (the major osmolyte). Conversely, cells doubled in size after the reciprocal downshock, there was rapid loss of about 70% of the cells' glycerol to the medium, a much smaller loss of cellular potassium and a steady disappearance of proline from the cells. The respiratory and photosynthetic responses to salinity fluctuations were also studied. Salinity downshocks stimulated respiration by 30% and inhibited photosynthesis by 16% within 5 min, but within 2 h these rates were identical to control rates. Upshocks caused a slight inhibition of respiration, but decreased photosynthesis by 40% within 5 min and recovery took 2 h. Downshocks had little effect on chlorophyll fluorescence, however, Fo strongly increased and both Fm and Fv/Fm declined within 5 min of salinity increases. This is consistent with a decrease in efficiency of PS2. Ecological and metabolic implications of the results are discussed.Abbreviations DMSO dimethyl sulphoxide - Hepes N-[2-hydroxyethyl]piperazine-N-2-ethane sulphonic acid - TCA trichloroacetic acid - Tris tris[hydroxymethyl]aminoethane     

The oral nerve plexus in amphioxus larvae: function,cell types and phylogenetic significance

Serial electron microscope reconstructions were used to examine the organization and cell types of the nerve plexus that surrounds the mouth in amphioxus larvae. The plexus is involved in a rejection response that occurs during feeding: a number of oral spines project across the mouth, and debris impinging on them triggers a contraction of the gill slit and pharyngeal musculature that forces water through the mouth, dislodging the debris. The oral spine cells are secondary sense cells that synapse with neurites belonging to a class of peripheral interneurons intrinsic to the oral nerve plexus. These in turn synapse with a second class of peripheral neurons with large axons that we interpret as sensory cells and which probably transmit signals to the nerve cord. The intrinsic cells also appear to synapse with each other, implying that local integrative activities of some complexity occur in the oral plexus. In comparative terms, the intrinsic neurons most closely resemble the Merkel-like accessory cells of vertebrate taste buds, and we postulate a homology between oral spine cells and taste buds, despite differences in function. There are also similarities between the amphioxus oral plexus and adoral nerves and ganglia of echinoderm larvae, suggesting homology of both the oral nerve plexus and the mouth itself between lower deuterostome phyla and chordates.