Characterization of Mendelian and Non-Mendelian Mutant Strains by Micronuclear Transplantation in Paramecium tetraurelia

ABSTRACT. Mutant strain d48 and d12 cannot express serotype A. In d48, the A i-antigen gene is present in the micronucleus, but not in the macronucleus. It has recently been shown that d12 contains the A gene in its micronucleus, but its macronucleus lacks the gene. Micronuclear transplantations into enucleated cells were performed to analyze those mutants. Reciprocal transplantation between wild type and d48 confirmed that d48 contains the A gene in the micronucleus and its cytoplasm is defective. Wild type 51 enucleated cells into which were transplanted d12 micronuclei could not express A. Amiccronucleate d12 cells into which were transplanted normal micronuclei from 51 or d48 showed no expression of A. These results show that even if the micronucleus of d12 contains the A gene, it must be abnormal, and its cytoplasm is also defective the same as d48. Genetic analysis showed that heterozygote of d12 and wild type 51 or d48 caused a cure of the cytoplasmic defect of d48 and d12 during the development of macronuclei.     

Is Geomagnetic Sensitivity Real? Replication of the Walker-Bitterman Magnetic Conditioning Experiment in Honey Bees

Although the presence of geomagnetic sensitivity has been suspectedfor a long time in a variety of marine and terrestrial animals,many responses reported in the literature have been based onextensive statistical analysis of orientation results or relyon obscure behavioral activities (like cetacean strandings orhoney bee waggle dances.) None of these reports have yet approachedthe level of clarity and simplicity displayed in experimentswith the magnetotactic bacteria, which is the best example ofgeomagnetic sensitivity in any living organism. Furthermore,claims of magnetic effects on living organisms pervade the literatureof biomagnetism, but many have failed subsequent attempts atreplication. We need to develop simple and easily replicatedexperiments for marine and terrestrial animals which can bemodified to answer basic questions concerning the psychophysicsof any geomagnetic sensory system which might be present. Inthis paper, we report the first replication of the Walker-Bittermanmagnetic anomaly conditioning experiment in honey bees, as wellas one of our attempts to slightly alter their basic protocol.We also report our attempts to condition honey bees to magneticdirection in simple maze experiments, and the initial resultsof a pulse-remagnetization experiment designed to test the ferromagnetictransduction hypothesis. We conclude honey bees are sensitiveto the geomagnetic field, that the signal processing for itis more complex than previously thought, and that a ferromagnetictransducer is compatible with all known behavioral data.     

Accumulation and Spatial Distribution of Poly(A)+RNA in Oocytes and Early Embryos of Drosophila melanogaster

We describe the accumulation and distribution of poly (A)⁺RNA during oogenesis and early embryogenesis as revealed by in situ hybridization with a radio-labeled poly (U) probe. The amount of poly (A)⁺RNA in nurse cell cytoplasm continuously increased untill mid-vitellogenic stage (st. 10), then decreased with the rapid increase of poly (A)⁺RNA in the oocyte (st. 11). The localization of poly (A)⁺RNA at stage 10 was in the anterior region of the oocyte, where it is connected by cytoplasmic bridge to the nurse cells. These observations indicate that most of the poly (A)⁺RNA synthesized in the nurse cells is transferred to the oocyte through the cytoplasmic bridges at stage 10–11. During the remainder of oogenesis (st. 11–14) and during preblastodermal embryogenesis, poly (A)⁺RNA was evenly distributed over the cytoplasm of oocytes and embryos. At blastoderm stage, poly(A)⁺RNA became concentrated in the peripheral region of embryos. Though the somatic nuclei of the blastoderm contained a detectable amount of poly (A)⁺ RNA, the pole cell nuclei did not. The cytoplasmic RNA visualised by acridine orange staining and the poly (A)⁺RNA detected by hybridization with [³H]poly (U) exhibited identical distributions during oogenesis and early embryogenesis. These observations provide a basis to assess the unique distributions of specific RNA sequences involved in early development.     

Light Actions in the Germination of Cocklebur Seeds: V. EFFECTS OF ETHYLENE, CARBON DIOXIDE AND OXYGEN ON GERMINATION IN RELATION TO LIGHT

Esashi, Y., Hase, S. and Kojima, K. 1987. Light actions in thegermination of cocklebur seeds. V. Effects of ethylene, carbondioxide and oxygen on germination in relation to light.–J.exp. Bot. 38: 702–710. Effects of ethylene, CO² and O² on the germination of after-ripenedupper cocklebur (Xanthium pennsylvanicum Wallr.) seeds wereexamined in relation to pre-irradiation by red (R) or far-red(FR) light In order to remove the pre-existing Pfr, seeds weresoaked in the dark for various periods prior to light irradiationand gas treatments. Regardless of light, 0.3 Pa C₂H₄ promotedgermination at 23 ?C, but it strongly inhibited germinationwhen applied at 33 ?C, the optimal temperature for the germinationof this seed. However, delayed application of C₂H₄ during 33?C incubation stimulated germination independently of lightin a similar manner to that seen at 23 ?C. It is, therefore,suggested that the germination-regulating action of C2H4 iscompletely independent of phytochrome. In contrast, the germination-promoting effect of 3–0 kPaCO₂ was pronounced only when the seeds were previously irradiatedby R, regardless of temperature, suggesting that CO₂ actionto promote germination depends upon Pfr. A synergism betweenCO₂ and C₂H₄ at 23 ?C was observed only in the germination ofseeds pre-irradiated by R, while at 33 ?C an antagonism occurredindependently of light. The stimulation of C₂H₄ production byCO₂ was most striking in the cotyledonary tissue pre-irradiatedby R. However, the R-dependent enhancement of CO₂-stimulatedC₂H₄ production was negated by the subsequent FR and it wasnot found in the presence of 1-aminocyclopropane-1-carboxylicacid (ACC). Moreover, the R dependency of the germination-promotingCO₂ effect disappeared in the presence of C₂H₄. The R-dependentC₂H₄ production enhanced by CO₂ may thus be involved, at leastpartially, in some step of conversion from methionine to ACC. The germination-promoting effect of C₂H₄, but not CO₂, was enhancedby O₂ enrichment regardless of light. However, the germination-promotingeffect of pure O₂ itself appeared to depend upon pre-irradiationwith R Key words: Carbon dioxide, cocklebur seed, ethylene, far-red light, germination, oxygen, red light, Xanthium pennsyloanicum     

Maternal Messenger RNA as a Determinant of Pole Cell Formation in Drosophila Embryos

Some polar plasm components are UV-sensitive. Messenger RNA extracted from oocytes or cleavage embryos can to induce pole cells in embryos that have been deprived of ability to form pole cells by UV-irradiation. This article reviews studies on the role of this mRNA in the developmental pathway leading to germ cell formation.     

消炎痛及PGF_(2α)对在体培养人子宫内膜出血的影响

利用甾体激素撤退方法造成移植在地鼠颊囊内人子宫内膜出血的动物模型,研究消炎痛和PGF_(2a)对内膜出血的作用。结果表明,注射三种不同剂量消炎痛并不能完全抑制内膜出血,但对内膜出血时间有延缓作用。用两种不同剂量的PGF_(2a)采取缓慢释放给药方法,虽然地鼠在给药后外周血液中PGF_(2a)水平比给药前显著增高,但内膜出血并不出现在撤退甾体激素之前。结果提示,PGF_(2a)对内膜血管破裂无直接作用,而纤溶活性变化可能是触子宫内膜出血更直接的原因。     

Macrophage Activation by Tetrahymena pyriformis II. Active Protein Fractions from Tetrahymena

ABSTRACT. Water-soluble and 0.6 M KCl-soluble protein fractions prepared from Tetrahymena pyriformis , when inoculated into mice, could effectively induce activated macrophages having the ability to kill Toxoplasma gondii in vitro. This effect was not induced by other proteins tested, such as bovine serum albumin, pepsin from porcine stomach mucosa and chicken egg-white lysozyme, nor by muramyl dipeptide (MDP), a potent immunoadjuvant. Five fractions obtained by DEAE-Sephadex chromatography of the water-soluble protein fraction were compared with regard to induction of toxoplasmacidal activity in macrophages. The first peak was most effective for activation of macrophages. Five fractions obtained by chromatography of the 0.6 M KCl-soluble protein fraction were also examined and it was found that the first peak had the activity. No marked difference in activity was observed between the active fractions of water-soluble and 0.6 M KCl-soluble protein fractions. For practical use, we focused on the water-soluble active fraction. The minimum effective dose of the active fraction was 100 μg and the fraction could activate macrophages directly in vitro. Four fractions obtained by gel filtration of the active fraction on Sephadex G-200 were compared and the first peak had the activity. The first peak contained a single protein, revealed by SDS-polyacrylamide gel electrophoresis; its apparent molecular weight was 64,000.     

The role of electrogenic xylem pumps in K+ absorption from the zylem of Vigna unguiculata: the effects of auxin and fusicoccin

Abstract We tested the hypothesis that electrogenic ion pumps, working at the parenchyma symplast/xylem interface of pea hypocotyls, provide the driving force for K⁺ uptake from the xylem. Solutions of known composition were perfused through a hypocotyl segment. The K⁺ activity of the solution flowing out of the xylem (K⁺_out) increased (i.e. K⁺ uptake decreased) when aerobic respiration was inhibited by lack of O₂, and this was preceded by a decrease in V_px (electrical potential difference between parenchyma symplast and xylem). Perfusion with auxin (1AA) and fusicoccin (FC) stimulated the electrogenic activity of the ‘xylem pumps’ (111 and 205% respectively) and stimulated uptake of K ⁺ from the xylem (with 71% and 29% respectively). The close correlation between xylem pump activity and K⁺ uptake corroborated the aforementioned hypothesis. Interestingly, inhibition of pump activity by anoxia was incomplete in the presence of FC. It is thought that FC increases the affinity of the ATP-requiring xylem pump for ATP, thus ensuring that ATP production during fermentation is sufficient to fuel the pump in the absence of O₂.     

Obstruction of Blastodisc Formation by Cytochalasin B in the Zebrafish, Brachydanio rerio

The blastodisc formation in the zebrafish, Brachydanio rerio , was obstructed by treatment with 1.0 μg/ml of cytochalasin B (CB), but not by 1.0 μg/ml of colchicine. The cortex in normal eggs contained a meshwork of microfilaments associated with the plasma membrane. The cortex was thicker at the vegetal pole and thinner at the animal pole of the egg. In CB treated eggs the cortex contained masses of microfilaments detached in places from the plasma membrane. Microtubules were never observed in the cortex of eggs with or without CB treatment. These results suggest that ooplasmic segregation, which results in blastodisc formation, is carried out by activity of the cortex, which contains CB sensitive microfilaments.