Clearance of bacteria and non-antigenic markers following intra-uterine inoculation into maiden mares: Effect of steroid hormone environment

Uterine response to inoculation with Streptococcus zooepidemicus organisms (antigenic markers) and 15-mum microspheres and charcoal (non - antigenic markers) was determined in seasonally acyclic maiden mares treated with either progesterone (P) n = 4, estradiol (E) n = 4 or oil vehicle (C) n = 4. At 3, 7 and 15 d after inoculation with bacteria and the 2 non - antigenic markers, uteri were flushed and the clearance of these materials, as well as the number of white blood cells and immunoglobulin concentration, determined. P-treated mares had higher numbers of bacteria and IgA and a greater volume of purulent fluid in the uterus than E- or C-treated mares at 7 d after inoculation. Clearance of inoculated materials began within 2 h in E-treated mares, and the non-antigenic markers were completely cleared in E- and C-, but not in P-treated mares, in 3 d. This suggests that in the P-dominated uterus, reduced physical clearance may contribute to an increased susceptibility to uterine infection.     

The immunocytochemical demonstration of Toxoplasma antigen in the brains of congenitally infected mice

The peroxidase anti-peroxidase immunocytochemical staining method was used to identify Toxoplasma antigen in paraffin embedded sections of the brains of 22 mice congenitally infected with the parasite. Intact Toxoplasma tissue cysts were readily demonstrated in the brain in all cases. In 4 of the 22 infected mice there was evidence of rupture of the cyst wall and/or presence of extra-cystic Toxoplasma antigen. Further support for the extra-cystic location of Toxoplasma antigen was obtained by electron microscopy of reprocessed tissue which revealed endozoites in the area immediately surrounding a ruptured cyst. The possible implications of these findings in relation to the pathogenesis of congenital toxoplasmic meningo-encephalitis are discussed.     

Phytoplankton population dynamics of a small reservoir: physical/biological coupling and the time scales of community change

This paper describes the day-to-day changes in species compositionthat resulted from intermittent wind mixing of the surface watersof a small reservoir. Two major scales of community change weredetected: a short-term (>1 day) scale associated with theredistribution of cells within the basin, and a 5–14-dayscale associated with growth responses. The physical scalesof change were found to be almost identical to the biologicalscales: wind stress caused changes in the temperature gradientof surface waters at scales of a day, and major vertical mixingevents occurred at scales of 10–14 days. The presenceof buoyant species ensured that rapid advection of populationsfollowed wind events. Community change was a function of bothadvection and growth, so that both real and apparent changesin abundance occurred. The observed seasonal succession wasboth a true succession and a changing sequence of populationsdependent on horizontal advection of water within the basin.Consistent stratification was present throughout the summerperiod and phytoplankton diversity was low. Even so, the seasonalsuccession was best described as a series of allogenic perturbationsfollowed by biological restructuring of the community. Dailysampling was necessary to document fully the mechanisms drivingthe seasonal succession of species.     

Chromosome 8 breakpoint far 3'' of the c-myc oncogene in a Burkitt''s lymphoma 2;8 variant translocation is equivalent to the murine pvt-1 locus.

The 2;8 variant translocation of human Burkitt's lymphomas is closely related cytogenetically to the t(6;15) of murine plasmacytomas; both involve a reciprocal exchange between the Ig kappa locus and a band region indistinguishable from that bearing the c-myc oncogene. To define their molecular relationship, we have compared cloned chromosome 8 DNA from the t(2;8) breakpoint in the human Burkitt's lymphoma JBL2 with cloned DNA from the murine pvt-1 locus, the major chromosome 15 breakpoint region in murine t(6;15). DNA sequencing and Southern blot analysis shows that these two regions are homologous. Thus the t(2;8) in JBL2 is the molecular equivalent of many murine t(6;15). The murine pvt-1 locus lies an unknown distance 3' of c-myc; analysis of DNA from several tumours with c-myc amplification reveals that pvt-1 is co-amplified in at least one case, placing pvt-1 approximately 100-500 kb 3' of c-myc. The significance of these results with respect to the role of pvt-1 in tumorigenesis is discussed.     

Menstrual cycle patterns of hormones and sexual behavior in gorillas

Oppositely sexed pairs of gorillas were tested behaviorally during the menstrual cycle to determine the relationship between hormone concentrations of the female and the frequency of sexual activity by the pair. Five females were tested individually during two cycles with each of two males, but serum samples for hormone assay were obtained from each female only during the first cycle of testing. There was no clear relationship between hormones and behavior for the single cycle in which the serum samples were obtained, with the exception that no copulations occurred after the early luteal phase, when progesterone was greater than 5 ng/ml. Normalized behavioral data from all four test cycles for all pairs suggested that female-solicited copulations were restricted primarily to the periovulatory period. Male sexual initiative (by one of the males) accounted for most copulations temporally dissociated from the periovulatory period. Normalized hormone data for all of the females suggested that (1) attractivity was associated with estradiol concentrations during the follicular phase, (2) proceptivity with estradiol and testosterone at midcycle, whereas (3) receptivity was not associated with hormone patterns or cycle phase. The data suggest that hormones are one of several variables that contribute to the regulation of sexual behavior in gorillas.     

On the O2 flash yields of two cyanophytes

We explored O₂ flash yield in two cyanophytes, Anacystis nidulans and Agmenellum quadruplicatum. On a rate-measuring electrode, a single flash gave a contour of O₂ evolution with a peak at about 10 ms which was maximum (100) for 680 nm background light. On 625 nm illumination the peak was smaller (62) but was followed by an increased tail of O₂ attributed to enhancement of the background. After a period of darkness, repetitive flashes (5 Hz) gave a highly damped initial oscillation in individual flash yields which finally reached steady state at 94% of the yield for 680 nm illumination. When O₂ of repetitive flashes was measured as an integrated flash yield the results was distinctive and similar to that for a continuous light 1 (680 nm). An apparent inhibition of respiration which persisted into the following dark period was taken as evidence for the Kok effect. With a concentration-measuring electrode, integrated flash yield vs. flash rate showed the same nonlinear behavior as O₂ rate vs. intensity of light 1. We draw three conclusions about the two cyanophytes. (a) The plastoquinone pool is substantially reduced in darkness. (b) Because of a high ratio of reaction centers, reaction center 1 / reaction center 2, for the two photoreactions, saturating flashes behave as light 1. (c) Because repetitive flashes are light 1, they also give a Kok effect which must be guarded against in measurements designed to count reaction centers.     

The effect of ACTH on the blood clearance rate of aldosterone, cortisol, 17 alpha-hydroxyprogesterone and 17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one in the sheep

The blood clearance rate (BCR) of aldosterone, cortisol, 17 alpha-hydroxyprogesterone (17 alpha OHP) and 17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one (17 alpha 20 alpha OHP) has been measured in conscious sheep prior to and after 5 or 6 days ACTH treatment. ACTH increased the BCR of cortisol but did not change the BCR of the other three steroids. 17 alpha OHP had a BCR greater than liver blood flow suggesting extra-hepatic metabolism. In vivo conversion of 17 alpha OHP to 17 alpha 20 alpha OHP by ovine red cells has been shown to be a significant site of this metabolism. It is suggested that this conversion of 17 alpha OHP to 17 alpha 20 alpha OHP may be important in the expression of the "hypertensionogenic" effect of 17 alpha OHP.     

Hemorrhagic enteritis in captive American kestrels (Falco sparverius)

Hemorrhagic enteritis and hepatitis of suspected adenovirus etiology were the apparent cause of death of nine captive American kestrels. Cloacal hemorrhage was the only prominent gross lesion: disseminated hepatocellular necrosis, and intranuclear inclusion bodies were evident microscopically. Electron microscopy revealed numerous adenovirus-like particles associated with the hepatic lesions. Attempts to serologically identify the agent were unsuccessful.     

Fatty acid composition of the lipids of Puffinus tenuirostris (Temminck) in relation to its diet

The fatty acid composition of lipids isolated from the depot fat, stomach contents, and proventricular oil of adult and chick Puffinus tenuirostris (Temminck) has been analysed. The diet of both adults and chicks is almost exclusively derived from the euphausiid Nyctiphanes australis Sars, and an attempt was made to determine whether dietary lipid affects the composition of depot fat, and whether individual fatty acids in the stomachs and proventricular oil can be used as markers for the origin of the diet. An apparent selectivity in the deposition of fatty acids in the fat depots can be explained by the conversion of fatty alcohols, derived from the euphausiid wax ester, into fatty acids of equivalent chain length and unsaturation. Hexadecadienoic acid appeared to be the only possible marker fatty acid from the euphausiid, but wide variations in its level limits its usefulness as a reliable index of the diet of Puffinus tenuirostris.