Algae have acquired plastids by developing an endosymbiotic relationship with either a cyanobacterium (primary endosymbiosis) or other eukaryotic algae (secondary endosymbiosis). We report a protist, which we tentatively refer to as Hatena, that hosts an endosymbiotic green algal partner but inherits it unevenly. The endosymbiosis causes drastic morphological changes to both the symbiont and the host cell architecture. This type of life cycle, in which endosymbiont integration has only partially converted the host from predator to autotroph, may represent an early stage of plastid acquisition through secondary symbiosis. 相似文献
To investigate the prevalence of diseases in the Borna disease virus (BDV) antibody positive race horses, we undertook seroepidemiological studies of BDV infection on 125 culled race horses in Hokkaido, Japan. The serological study disclosed the presence of antibodies only to BDV-p40 or -p24 in 19.2% (24/125) and 3.2% (4/125) of culled horses, respectively. Antibodies to both BDV-p40 and -p24 were found in 24.0% (30/125) of these horses. Of particular note was the finding that locomotorium disorders were detectable at a significantly higher rate in BDV antibody positive horses than that in the seronegative horses. These results imply that BDV infection may possibly contribute to an increase in the incidence rate of locomotorium disorders in race horses. 相似文献
We have studied the quantitative analysis of potassium in agricultural materials by measuring the radioactivity of K4o by means of Radiation Counter since 1951. When the fundamental experiment was almost over and we were to begin the applications in fertilizers and crops, we found unexpectedly in May 1954, rain containing fission products presumably carried from H-bomb explosion test at Bikini. Temporarily abstaining from the experiment, we surveyed the degree of contamination of radioactive substances in crops, especially grapes, which are the main horticultural crop in this prefecture. Here, we explain the experimental data of the radioactivity in the grapes and the relations between the contamination of the artificial radioactivity and the potassium content in them. 相似文献
Although chinese yam plants are an important crop in Japan, relatively little is known about their content of the organic constituents. IZAWA and NATAKE (1,2,3) showed some aspects of the effect of the fertilizer treatment on the organic composition of chinese yam plants at various phase of their vegetation. Many reports on chinese yam plants have appeared; nevertheless, the nature of carbohydrate and nitrogen metabolism has remained unknown. However, there are a number of excellent reports (4, 5, 6) which directly or indirectly have a bearing on these biochemical phase in sweet Potato plants. Therefore, the objectives of the Present study were twofold : a) to determine the contents of sugars, starch, alcohol-insoluble solids, and various nitrogen constituents in sweet potato plants during growth as affected by mineral nutrition, and b) to compare the effect of mineral nutrition on sweet potato plants with its effect on chinese yam plants. 相似文献
Seedlings of bok choy and tomato were grown in soils with different nitrogen (N) sources [no N (?N), ammonium sulfate (AS), and cattle farmyard manure (CM)]. Comparison between soils treated with ?N and CM indicated that the growth and N accumulation in bok choy were significantly enhanced by CM treatment, whereas no difference was found in tomato. In the rhizosphere soils, the highest protease activity was detected in CM treatment irrespective of species. Correlation analysis between rhizospheric protease activity and total N accumulation of plant treated with –N and CM showed a significant positive correlation only for bok choy. The determination of amino acid absorption rate in excised roots indicated that glycine was taken up at a significantly higher rate in bok choy than tomato. This study suggested that at least two possible factors affected the acquisition of organic N: rhizospheric protease activity and ability to absorb amino acids in roots. 相似文献
The chromosomal banding patterns of canine normal chromosome were analyzed by G-, Q-, C- and N-banding techniques. The chromosomes of canine normal lymphocytes consisted of 38 acrocentric autosome pairs and X-, Y-metacentric sex chromosomes. Their G- and Q-banding patterns corresponded to the those reported by Manolache et al. in 1976. C-bands of chromosomes were found on the centromeric regions of the 7th, 26th, 34th, 35th, 37th and 38th pairs of chromosomes. In addition, N-bands whose location had not been confirmed until now were recognized on the telomitic regions of the 7th, 9th and 22nd pairs of chromosomes. 相似文献
1. Fourteen‐week‐old intact and castrated cockerels (White Leghorn) were injected intramuscularly with zinc (100 μg/kg body weight) as zinc ammonium sulphate solution once daily for 4 weeks and the effects on testes, pituitary and adrenal glands investigated histologically.
2. In intact cocks zinc decreased testes weight significantly, inhibited spermatogenesis and disturbed testicular hormone production. There was an increase in pituitary gonadotrophic cell activity, perhaps an indication of feed‐back response to low concentration of testicular hormone. Cortical and medullary cells of the adrenal glands showed signs of activation.
3. No discernible effects of zinc injection on pituitary and adrenal cells of castrates were observed. This may reflect a decrease in pituitary and adrenal responsiveness to repeated stimulation with zinc.
4. The results indicate that the effectiveness of a given dose of zinc was dependent on the physiological condition of the cockerels and the effective site of zinc action was centred in the testes. 相似文献
We investigated the effect of fucoidan, a sulfated polysaccharide, on acceleration of healing of experimental cartilage injury in a rabbit model. An injured cartilage model was surgically created by introduction of three holes, one in the articular cartilage of the medial trochlea and two in the trochlear sulcus of the distal femur. Rabbits in three experimental groups (F groups) were orally administered fucoidan of seven different molecular weights (8, 50, 146, 239, 330, 400, or 1000 kD) for 3 weeks by screening. Control (C group) rabbits were provided water ad libitum. After the experimental period, macroscopic examination showed that the degree of filling in the fucoidan group was higher than that in the C group. Histologically, the holes were filled by collagen fiber and fibroblasts in the C group, and by chondroblasts and fibroblasts in the F groups. Image analysis of Alcian blue- and safranin O-stained F-group specimens showed increased production of glycosaminoglycans (GAGs) and proteoglycans (PGs), respectively. Some injured holes were well repaired both macroscopically and microscopically and were filled with cartilage tissues; cartilage matrices such as PGs and GAGs were produced in groups F 50, F 146, and F 239. Thus, fucoidan administration enhanced morphologically healing of cartilage injury. 相似文献