Chromatographic Studies of Sera from Calves Vaccinated with Brucella Abortus, Strain 19

The presence of antibody was detected by agglutination tests in the serum of calves four days after vaccination with Brucella abortus strain 19. Titres had reached a maximum by seven to ten days post-vaccination. Sucrose density-gradient ultracentrifugation demonstrated that the earliest antibodies were macroglobulins, IgM (19Sγ; γM)-globulins. Lighter antibodies, IgG (7Sγ₂; γG)-globulins, appeared a few days later. With time, antibody titres fell, IgM declining somewhat more quickly than IgG. After revaccination some seven months later, there was a rapid rise in both IgM and IgG.

Anion-exchange column chromatography (DEAE-cellulose) and gel filtration (Sephadex G-200) were applied in separating the two forms of antibody. The former method, in which a gradient buffer system was used, proved to be the more efficient; the IgG antibodies apeared in early eluates at pH 7.8 to 8.0 and low ionic strength, 0.03M, whereas IgM was eluted late when the pH had fallen below 6.0 and the molarity had increased to beyond 0.2. DEAE cellulose chromatography detected IgG as well as IgM sera collected as early as five days after vaccination.

     

Field trial of the efficacy of a combination of ivermectin and praziquantel in horses infected with roundworms and tapeworms

Two hundred and thirty-three horses were screened for the presence of roundworms by faecal egg counts (FECs) and for tapeworms by an ELISA specific for antibodies to the immunodominant 12 kDa and 13 kDa tapeworms antigen. The 62 horses were found to be infected with both parasites were treated with a combination of 0.2 mg/kg ivermectin and 1.5 mg/kg praziquantel. The treatment suppressed the median FEC of the horses to zero for 10 weeks and significantly reduced their anti-12/13 kDa antibody levels. The estimated risk of tapeworm-associated colic in these horses was halved by 12 weeks after the treatment.     

Use of chemokine receptors by poxviruses

Chemokine receptors serve as portals of entry for certain intracellular pathogens, most notably human immunodeficiency virus (HIV). Myxoma virus is a member of the poxvirus family that induces a lethal systemic disease in rabbits, but no poxvirus receptor has ever been defined. Rodent fibroblasts (3T3) that cannot be infected with myxoma virus could be made fully permissive for myxoma virus infection by expression of any one of several human chemokine receptors, including CCR1, CCR5, and CXCR4. Conversely, infection of 3T3-CCR5 cells can be inhibited by RANTES, anti-CCR5 polyclonal antibody, or herbimycin A but not by monoclonal antibodies that block HIV-1 infection or by pertussis toxin. These findings suggest that poxviruses, like HIV, are able to use chemokine receptors to infect specific cell subtypes, notably migratory leukocytes, but that their mechanisms of receptor interactions are distinct.     

Cell sorting: automated separation of mammalian cells as a function of intracellular fluorescence

A system for high-speed sorting of fluorescent cells was able to sort mouse spleen cells from Chinese hamster ovarian cells after development of fluorochromasia. Highly fluorescent fractions separated after similar treatment from mouse spleen cells immunized to sheep erythrocytes were enriched in antibody-producing cells by factors of 4 to 10.     

Chlorine oxide in the stratospheric ozone layer: ground-based detection and measurement

Stratospheric chlorine oxide, a significant intermediate product in the catalytic destruction of ozone by atomic chlorine, has been detected and measured by a ground-based 204-gigahertz, millimeter-wave receiver. Data taken at latitude 42 degrees N on 17 days between 10 January and 18 February 1980 yield an average chlorine oxide column density of approximately 1.05 x 10(14) per square centimeter or approximately 2/3 that of the average of eight in situ balloon flight measurements (excluding the anomalously high data of 14 July 1977) made over the past 4 years at 32 degrees N. We find less chlorine oxide below 35 kilometers and a larger vertical gradient than predicted by theoretical models of the stratospheric ozone layer.     

The visual impact of gossip

Gossip is a form of affective information about who is friend and who is foe. We show that gossip does not influence only how a face is evaluated--it affects whether a face is seen in the first place. In two experiments, neutral faces were paired with negative, positive, or neutral gossip and were then presented alone in a binocular rivalry paradigm (faces were presented to one eye, houses to the other). In both studies, faces previously paired with negative (but not positive or neutral) gossip dominated longer in visual consciousness. These findings demonstrate that gossip, as a potent form of social affective learning, can influence vision in a completely top-down manner, independent of the basic structural features of a face.