Recognition of Non-self in Crustaceans

This paper reviews the current concepts of recognition of non-selfin crustaceans and relates these concepts to recognition inthe invertebrates in general. It focuses primarily on a decapodcrustacean, the blue crab(callinectes sapidus)and on resultsusing this animal as a model to study the clearance of virusesand xenogeneic proteins. Clearance studies indicate that bluecrabs possess a quasi-specific recognition system in the normalor "non-immunized"state. This system is capable of rapidly clearingforeign proteins and certain viruses from the circulation, andresults in concentration of such proteins into the gills andviruses into the hepatopancreas or gills. Although humoral factorswhich bind foreign proteins or neutralize viruses have beenisolated, transfusion exchange experiments involving depletionof circulating cells and/or humoral factors indicate that theblue crab does not require circulating hemocytes or humoralfactors for clearance of foreign proteins. These results suggestthat a population of fixed cells, possibly those in the gills,may be the critical component for recognition of foreign proteinsby normal crabs.     

Incorporation of Radioactive Pyrimidine Nucleosides into DNA and RNA of Eimeria tenella (Coccidia) Cultured In Vitro*

Autoradiographic methods were used to study the incorporation of tritiated cytidine, thymidine, and uridine into asexual stages of Eimeria tenella cultured in embryonic chick kidney cells. Developing parasites did not incorporate ³H-thymidine either when host cells were labeled prior to infection or when the cultures were labeled for 30 min, 48–72 hr after infection. Continuous exposure of infected cultures to ³H-thymidine for up to 18 hr resulted in light labeling of cell cytoplasm and schizonts. ³H-cytidine and ³H-uridine were incorporated into parasites developing in cultures that were labeled before infection. When the cultures were labeled for 30 min, 48–72 hr postinfection and fixed immediately, schizonts were labeled lightly with ³H-cytidine but contained dense accumulations of ³H-uridine.     

Hammondia pardalis sp. n. (Sarcocystidae) from the Ocelot, Felis pardalis, and Experimental Infection of Other Felines

Synopsis.
Hammondia pardals sp. n. (Eimeriorina: Sarcocystidae) from Panama Canal Zone is described as an obligate heteroxenous coccidian, with felids as the final host and laboratory mice as the experimental intermediate host. Ovoid oocysts. measuring 40.8 (36–46) × 28.5 (25–35) m. are shed unsporulated. Oocysts were infective only for the intermediate host. the laboratory mouse, Mus musculus , and the intracellular cysts were infective only for felids. Attempted passage of tissue cysts from mouse to mouse was unsuccessful.
Mice fed 5 × 10⁴ sporulated oocysts were found to harbor small intracellular cysts, 13–16 × 10–15 m, in the mesenteric lymph nodes, lungs, and intestinal submucosa 15 days postinfection. The meronts in these early cysts were stubby and measured 3 × 6 m. The prepatent period in the felids was 5 to 8 days and the patent period 5–13 days. Experimental infections of definitive hosts were successful with 6/6 domestic laboratory-reared kittens, Felis catus ; 5/5 ocelots, F. pardalis ; and 1/1 jaguarundi, F. yagouaroundi. None of the exposed raccoons, Procyon lotor , shed oocysts.     

The Effects of pH,Buffers, Bile and Bile Acids on Excystation of Sporozoites of Various Eimeria Species*

SYNOPSIS. Oocysts of Eimeria bovis were found to undergo excystation when subjected at 39 C to a pretreatment consisting of exposure for 24 hr to CO₂ and air (50–50), and a treatment for 7 hr with a mixture of bile and trypsin. At pH's of 6.0 thru 10.0 with tris-maleate buffer, excystation occurred over the entire range of pH tested, with the highest levels at pH 7.5-8.5. No adverse or inhibitive effect on excystation or the viability of the sporozoites was observed. Disintegration of sporozoites occurred within the sporocysts of intact oocysts at each of the pH levels studied when boric acid-borax, ammediol, and glycine-sodium hydroxide buffers were used in the treatment medium. Phosphate buffer inhibited excystation when used in the excysting medium. Excystation occurred at levels above 90% in all dilutions of taurocholic, glycocholic, glycotaurocholic, and cholic acids included in the study (0.5-10.0%) except for the 10% and 5% dilutions of cholic acid and the 10% dilution of glycotaurocholic acid. In the latter 3 dilutions, sporozoites within the sporocysts of intact oocysts disintegrated. Excystation levels above 90% were observed in the 50% and 10% dilutions of fresh bovine bile, and in the 5% dilution of lyophilized bovine bile. Lower levels of excystation occurred in greater dilutions of both kinds of bile. No excystation occurred when any of the bile acids, fresh bovine bile or lyophilized bile were used without trypsin, except for fresh bile that contained a heavy suspension of bacteria and fungi. In a medium containing trypsin and heat-treated bile, heat-treated bile acids, or no bile, 2.5–8% of the oocysts excysted. The findings indicate that satisfactory excystation can be obtained with a treatment medium containing tris-maleate at pH 7.5–8.5, 0.25% trypsin, and 1% of one of the bile acids.     

The Effect of Interleukin-2 on Parasitemia and Myocarditis in Experimental Chagas' Disease

Previous investigations showed that interleukin-2 (IL-2) administered in vivo into mice infected with Trypanosoma cruzi reduced levels of parasitemia and increased longevity. Present experiments examined the effect of administration of different doses of IL-2 at different times during infection in mice on parasitemia and histopathoiogy of heart tissue. Two different doses of IL-2 (1,500 or 10,000 U) given at 3 different times during infection were equivalent in reducing parasitemia. All of the IL-2 treated groups of mice had significantly lower numbers of circulating trypomastigotes as compared with controls not receiving this fymphokine. This IL-2 treatment of T . crazi-infected mice resulted also in lower numbers of pseudocysts in all 4 ventricular regions in the hearts. This was particularly evident in the more severely infected right ventricular wall; however, a similar decrease was not as apparent in the less severely infected left ventricular wall. The IL-2 treated, infected mice showed minimal or no effect in reducing inflammation of myocardial cells. However, the mildest inflammation of ventricular wall tended to occur in mice receiving IL-2 treatment either as a low dose (1,500 U) or a high dose (10,000 U) at 5, 7 and 9 days after infection as compared with mice treated later on. It was concluded that IL-2 treatment of infected mice produced a significant decrease in parasitemia and decreased infection of myocardial cells. Key words. Heart, histopathoiogy, inflammation, lymphokine, myocardial cells, pseudocyst, Trypanosoma cruzi .     

Systematic anatomy of Oceanopapaver, a monotypic genus of the Gapparaceae from New Caledonia

Evidence from vegetative anatomy, reproductive morphology, and palynology does not support a relationship of Oceanopapaver with Cistaceae, Cruciferae, Flacourtiaceae, Papaveraceae, and Tiliaceae, but suggests placement of the genus in Capparaceae. The apparent occurrence of myrosin cells, among other features, effectively excludes all of the aforenoted families except Capparaceae and Cruciferae. However, multicellular non-glandular trichomes, bracteate inflorescences, sepals and petals each occasionally other than four per flower, presence of an androgynophore, numerous stamens, tricolporate and binucleate pollen, the unilocular mature ovary, the stipitate fruit, and the exotegmic seed in Oceanopapaver favour Capparaceae over Cruciferae. Floral histology and vasculature provide no clues about the relationships of Oceanopapaver. A few features are anomalous, most notably the presence of secretory canals and secretory cells in the genus versus their absence in Capparaceae and their rarity in Cruciferae, the trichomic floral nectary in the genus versus the massive, non-trichomic nectaries in these two families, and the straight embryo in the genus versus the more or less curved or folded embryo in the two families. The fleshy endosperm in Oceanopapaver has counterparts in a few Capparaceae, contrary to previous claims that endosperm is absent or scanty in this family. The report of stamen fascicle traces for Oceanopapaver is the first for Capparaceae, but these should be sought elsewhere in the family. Within Capparaceae the genus fits best in Capparoideae compared to Cleomoideae or the nine other very restrictive subfamilies variously proposed for Capparaceae. There is no justification for the monotypic segregate Oceanopapaveraceae. The phylogenetic and functional anatomy of vegetative and reproductive structures is discussed.     

The ecology and evolution of male reproductive behaviour in the bees and wasps

Males of aculeate Hymenoptera differ in the behavioural adaptations employed to locate and secure mates. The ecological and evolutionary bases of these differences are explored in this paper. Male bees and wasps search for females by patrolling widely within emergence-nesting areas or within patches of flowers attractive to conspecific females, or by waiting at landmarks, at specific emergence sites, or at nests. Nest dispersion, flower distribution, the type of female mating system and the nature of male-male competition appear to be key factors in determining the mate-locating behaviour of males. Of special interest in multiple-mating by females, which may be an evolutionary response to the costs of attempting to resist copulation in certain situations. When polyandry occurs, males are under selection pressure to be the last male to copulate with a female prior to oviposition if sperm precedence occurs. In species in which females mate just once, a selective premium is placed on being the first male to reach a virgin female. In either case, because receptive females are a limited resource, there is intense competition among males for access to the resource. The density of competitor males may play an important role in determining whether holding a relatively restricted territory is preferable to the strategy of patrolling widely at various sites which may have females. Territoriality is practiced by males of several species of aculeate Hymenoptera when the number of male competitors is relatively few in number and the distribution of emergence sites or foraging areas of females is clumped in space.     

Morphometric studies in inbred and hybrid house mice. Heterosis, homeostasis and heritability of size and shape

One size (SIZE) and four shape measures (SHAPE 1-SHAPE 4) were derived from a multiple group principal components analysis of 15 osteometric variables in inbred and hybrid house mice. In both sexes, SIZE and two of the four SHAPE variables showed positive heterosis, the other two SHAPE variables exhibiting negative heterosis. SIZE showed a greater magnitude of heterosis (average of about 2.3 standard deviations) than all SHAPE characters except SHAPE 2, a skull length/width contrast. Inbreds were more variable than hybrids (positive homeostasis) for all characters, and there was a significant, positive correlation between heterosis and homeostasis in these characters. The reciprocals category in hybrids was more important for SIZE than for the SHAPE variables, presumably because maternal effects have a greater influence on growth characters. Broad-sense heritabilities for SIZE were 0.8 in inbreds and 0.6 in hybrids whereas they averaged only 0.4 for the SHAPE variables. It was postulated that there is a greater number of loci governing SIZE compared to SHAPE, and that this explains both the heritability and heterosis differences between these characters.     

CALCIUM PROVISION TO EGGS IN TWO POPULATIONS OF HELIX ASPERSA BY PARENTS FED A DIET HIGH IN LEAD

The reproductive performance of two populations of Helix aspersawith different histories of exposure to lead was assessed bytheir egg production, hatching success and the metal contentof the eggs. By using laboratory-bred parents raised in a Pb-freeenvironment, the possibility of an inherited response to a highPb exposure was assessed. Following a period of dormancy, six individuals in each population werepaired for copulation and allowed to oviposit. During this time theywere fed a diet with 500 µg.g^-1 Pb, for a total of 14days. After oviposition, the egg mass from each pairing was weighed,counted and samples analysed. Metal concentrations in four tissuefractions of the parents (shell, hepatopancreas, reproductive systemand rest9) were also analysed. There was no significant transfer of Pb to the eggs in either population.There were differences in their egg massesthe population froman uncontaminated site, Rottingdean (RD), laid, on average,twice the number of eggs of the snails from Minera (MI), a contaminatedsite in North Wales. However the latter had a higher averagepercentage emergence (90% compared to 55% for RD). There wasalso considerable hatching asynchrony in the RD offspring, whilehatching within each MI egg mass was completed within two days.This is discussed in relation to the Ca status of the parentand possible differences in reproductive strategy between thetwo populations. (Received 22 February 2000; accepted 8 May 2000)