In vitro Development of First-Generation Schizonts of Eimeria canadensis (Bruce, 1921)*†

SYNOPSIS. In vitro development of Eimeria canadensis from cattle was studied in monolayer cultures of various bovine cell lines grown on coverslips in Leighton tubes. Excysted sporozoites were used for inoculation of the cell cultures. Sporozoites entered the host cells within a few minutes, but apart from a reduction in the number of refractile bodies, changed little in appearance during the first 9 days. Beginning at 91/2 days postinoculation, sporozoites developed into sporozoite-shaped schizonts or, less frequently, transformed into trophozoites. Sporozoite-shaped schizonts with as many as 8 nuclei were observed transforming into spheroid schizonts. At 111/2 days, intermediate schizonts had a characteristic single mass of refractile granules and 60–80 nuclei. Deep invaginations, which resulted in the formation of several blastophores, usually occurred when schizonts had about 100 nuclei. Merozoites were formed as a result of radial outgrowth from the surface of spheroid schizonts as well as of blastophores. Mature merozoites were seen 1st after 13 days.     

Effect of Antilymphocytic Serum on Circulating Interferon in Mice as a Function of the Inducer

MOST investigators concerned with interferon synthesis in vivo have used the experimental procedure described by Baron and Buckler¹, in which circulating interferon is induced by intravenous administration of viruses. When interpreting results, however, it is difficult to know which cells are responsible for circulating interferon synthesis in the animal. Using a radiobiological approach, we have shown that after an intravenous injection of virus, interferon released into the blood stream of mice originates in cell populations of varying radiosensitivities, depending on the virus inoculated². Myxo-virus-induced circulating interferon production is characterized by high radiosensitivity, for serum interferon titres are decreased by more than 90% in C3H/He mice after one total body X-irradiation of 250 r. Moreover, the species specificity of interferon has enabled us to show that circulating interferon induced by Newcastle disease virus (NDV) is of donor type in xenogeneic radiochimaeras, from which we concluded that cells responsible for interferon synthesis with this virus originate from haemopoietic stem cells^3,4. Both granulocytes and lymphocytes fulfil the criteria of very radiosensitive elements derived from haemopoietic stem cells^5,6. We wish to report that myxovirus-induced circulating interferon production is selectively depressed after administration of antilymphocyte serum (ALS).     

绒毛膜促性腺激素及其α、β亚单位抗体的抗生育作用

本文研究结果证明给小白鼠子宫分别注射特异的抗hCG及其α、β亚单位血清后,唯有抗hCG及β亚单位血清能表现出显著的抗生育作用。这一结果在经纯化过的hCG及卢亚单位免疫球蛋白G的相同实验中也得到了验证。从而证实着床前的小白鼠胚泡中存在hCG样糖蛋白物质。 特别使人感兴趣的是这类抗体只对妊娠第三天的小白鼠胚泡的着床有明显的抑制效应,这是一个前所未曾遇见的问题。     

Photo-oxidative Degradation of Chlorophyll-a and Unsaturated Lipids in Liposomal Dispersions at Low-Temperature

Liposomal dispersions in water were used as a tool to study photo-oxidation of chlorophyll-a and photo-oxidation of unsaturated lipids at 1 or 4°C. The presence of monogalactosyl diglyceride stimulated chlorophyll-a degradation. In addition the level of linolenic acid was decreased in liposomal dispersions containing chlorophyll-a, dipalmitoyl phosphatidyl choline, and monogalactosyl diglyceride, indicating that monogalactosyl diglyceride and chlorophyll-a were coupled in the preparations. In liposomal dispersions containing equal (molar) quantities of a-tocopherol, monogalactosyl diglyceride, and chlorophyll-a, a-tocopherol fully protected linolenic acid against photo-oxidative degradation, while chlorophyll-a degradation was only slightly reduced. In liposomal preparations containing a-tocopherol, chlorophyll-a and phosphatidyl choline, a-tocopherol catalyzed degradation of chlorophyll-a. Absorption spectra of the liposomal dispersions showed that the presence of a-tocopherol caused increased absorption in red light, which was attributed to structural changes in the liposomal preparations and thus could explain the noted effects. Tocopherol itself was rapidly degraded in chlorophyll-a containing liposomal preparations. Complex formation between chlorophyll-a and monogalactosyl diglyceride in chloroplasts is suggested and protection by a-tocopherol against photo-oxidation in chilling-sensitive plants; a suggestion which is founded on the similarities that exist between chloroplast preparations and liposomal preparations containing chlorophyll-a and monogalactosyl diglyceride as regards photo-oxidative degradation of chlorophyll-a, a-tocopherol and linolenic acid.     

Effect of α-Tocopherol, β-Carotene, Monogalactosyldiglyceride and Phosphatidylcholine on Light-Induced Degradation of Chlorophyll a in Acetone

The effect of α-tocopherol, β-carotene, monogalactosyldi-glyceride and phosphatidylcholine on red light induced degradation of chlorophyll a was studied in acetone at 4°C. Monogalaclosyldi-glyceride was ineffective up to a molar ratio of monogalactosyldi glyceride to chlorophyll of 1:10. α-Tocopherol, β-carotene and phosphatidylcholine inhibited chlorophyll degradation. Maximal protection by α tocopherol and β-carotene was similar (76%) but on a molar basis a tocopherol was less effective. Protection by phosphatidylcholine was less than by a tocopherol and α-carotene but the lipid was effective at a lower ratio of chlorophyll to protectant. Inhibition by phosphatidylcholine was independent of the degree of unsaturation of the fatty acids. Effects of β-carotene and α-tocopherol were additive at suboptimal concentrations, but addition did not increase the maximal protection of 76% by these substances alone. Phosphatidylcholine increased the effectiveness of α-tocopherol and β-carotene independent of their concentrations. It is suggested that interactions between lipids participate in the mechanism protecting chlorophyll a against photooxidation in the chloroplast membrane.     

Influence of ecdysterone, precocene and compounds with juvenile hormone activity on induction, termination and maintenance of diapause in the parasitoid wasp, Nasonia vitripennis

ABSTRACT. Using the Galleria bioassay, no difference could be found between the JH titre of diapausing and developing Nasonia larvae. Compared to the values found in some Lepidoptera, the JH titres in Nasonia larvae are low, c. 14 Galleria units/g live weight. Induction of diapause could not be brought about by topical application of JH I, JH analogues, precocene, or ecdysterone to the maternal generation, nor by treating eggs or larvae with compounds with JH activity. Diapause was easily terminated by topical application of ecdysterone, however. If ecdysterone treatment was preceded by JH-treatment, the percentage of larvae terminating diapause was reduced: JH II seems to be more potent than JH I or JH III in this effect if the interval between JH and ecdysterone treatment is 72 h.     

A Comparison of Methods and the Validity of Deoxyribonuclease Tests for the Characterization of Staphylococci Isolated from Animals

Strains isolated from pigeons belonging to the coagulase-positive species Staphylococcus intermedius , coagulase-negative Staph. hyicus subsp. chromogenes strains from cattle and pigs, and Staph. aureus strains from poultry, gave weakly positive reactions in DNase plate culture tests and heat-resistant DNase tests. Staph. aureus and Staph. intermedius strains from other sources and coagulase-negative and coagulase-positive Staph. hyicus subsp. hyicus strains reacted strongly in these tests. A standardized plate culture test procedure is proposed and the use of DNase tests in the identification of staphylococci isolated from animals is discussed.     

Phylogenetic relationships in Ephedra (Ephedraceae) inferred from chloroplast and nuclear DNA sequences

Sequences of the nuclear ribosomal DNA internal transcribed spacer region 1 and the chloroplast-encoded genes maturase K and ribulose-1,5 biphosphate carboxylase large subunit were obtained from species of Ephedra (Ephedraceae) representing the geographic range and morphological diversity of the genus. Phylogenetic analyses of the DNA data indicate that relationships within the genus are better predicted by geographic region of origin than by ovulate cone characters. The sampled species with dry, winged (versus fleshy) ovulate cone bracts or single-seeded cones do not form monophyletic groups and therefore the previous classification systems of Ephedra based on these aspects of bract morphology appear to be largely unnatural. Three groups were identified among the Old World species studied, one comprising European and Mediterranean species and two including only Asian species. The sequence data suggest a possible early divergence of a New World clade of Ephedra from among the Old World groups. The South American species form a distinct clade apparently related to one of two groups of North American species, which accords with a frequent floristic pattern of close relationships between species groups in western South America and southwestern North America.