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1.
Results of histopathological examination of a solitary chronical amoebic abscess in the liver of a patient from Cambodia are described. The abscess was at a proliferously reparative phase and Entamoeba histolytica was detected at the border between the necrosis and inner wall of abscess, as well as in the proper non-specific granulation tissue of the inner layers of abscess capsule. A differential diagnosis of the amoebic abscess from similar parasitary or pseudoparasitary liver lesions and differential diagnosis of amoebae in histological sections are given. For orientation examinations of the liver tissue for the presence of amoebae the authors recommend the impregnation after Grocott and staining with Goldner's trichrome for a more detailed evaluation of histological sections. 相似文献
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L Cerva 《Folia parasitologica》1978,25(1):1-8
The effects of pH, various viscosity of the medium, changed ratio between the concentrations of dissolved and corpuscular components in the medium, and dissolved inorganic salts on the growth of axenic cultures of Naegleria fowleri and N. gruberi have been studied. The cultures were grown in liquid CALYG and BCS media. The pH optimum was 6.5 for N. fowleri and 6.0--6.5 for N. gruberi. No negative influence on the growth of N. fowleri was observed even at 0.5% concentration of highly viscous methylcellulose, whereas the growth of N. gruberi was distinctly inhibited by more than 0.2% of methycellulose. N. fowleri preferred the osmotorphic and N. gruberi phagotrophic nutrition in the given system of cultivation. The growth of both Naegleria species was inhibited by 0.1 N concentration of sodium chloride and potassium chloride without any significant difference in the tolerance. The inhibitory effect of these salts correlated primarily with the concentration of chloride anion. The ability to grow in a medium with increased viscosity and the preference for osmotrophic nutrtion are, besides the higher temperature optimum determined earlier, further characteristics of the pathogenic species N. fowleri. 相似文献
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This is a follow-up report on the viability of pathogenic Naegleria fowleri, Naegleria australiensis and Acanthamoeba castellanii isolates during 5 to 10 years of cryopreservation at -70 degrees C. The greatest decrease in viability occurred with N. fowleri and the least occurred with N. australiensis. At 10 years of cryostorage, viability was 21% for N. fowleri, 32% for A. castellanii and 51% for N. australiensis. 相似文献
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Dynamics of granular leucocyte response in peripheral blood of naive and sensitized pigeons infested with Argas polonicus larvae was only slightly dissimilar. In both cases a marked increase of heterophil and eosinophil counts and only a mild increase of basophil count were recorded at 6 hours post-infestation. In naive hosts the basophil count increased again at 96 hours post-infestation, but in sensitized hosts it did so as early as 48 hours post-tick attachment and was also accompanied by an increase of eosinophil levels 72 and 96 hours post-infestation. Cutaneous response of sensitized hosts at the tick feeding site was characterized by a large heterophil accumulation at 24 hours post-infestation, by an increased eosinophil count at 48 hours and basophil counts at 72 and 96 hours post-infestation. In primary hosts lesions were characterized by a mild increase of heterophil count later than 48 hours post-infestation and by slight eosinophil accumulations at 24 and 48 hours post-tick attachment, as well as basophil accumulation as late as 96 hours post-infestation. Cutaneous lesions of sensitized hosts were accompanied by apparent inflammatory changes which were mild and sometimes missing in primary hosts. Cytotoxic and degenerative alterations of basophils and other granulocytes were observed as well as vesiculation of secretory granules of basophils. Cutaneous response of sensitized hosts to larval A. polonicus feeding can be characterized as a cutaneous basophil hypersensitivity. 相似文献
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通过在旱区坡耕地上模拟降雨试验,研究在降雨强度40 mm·h-1和历时为3 h的条件下,7种线性水溶性高分子聚合物（PAM）和新型节水保水材料（SAP）交并施用方式对径流和氮素淋溶的影响。结果表明：与对照处理（不施用PAM和SAP）相比较,施加PAM和SAP有效减少了径流量和氮素淋溶量,减少的地表径流量达93.29%,相应地降低水中总氮淋溶量达25.58%,保水作用SAP强于PAM;同时,减少的土壤侵蚀量达91.85%,相应地降低泥沙中总氮淋溶量达37.96%;由降雨后土壤剖面养分分布可知,0~15 cm深度土壤的含氮量比对照组高50.24%。说明施加PAM和SAP增加了根系层的持水和保肥能力,降低了土壤养分随水的深层渗漏,且保土作用PAM强于SAP。在坡耕地施加PAM和SAP不但可以减少水土流失,而且能降低土壤氮素的流失,防止肥料对地下水的污染。 相似文献
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PRELIMINARY STUDIES ON THE TRANSLOCATION OF 14 C-LABELLED HERBICIDES IN BRACKEN (PTERIDIUM AQUILINUM)
G. I. McINTYRE 《Weed Research》1962,2(1):51-59
Summary. The translocation of 14 C-labelled herbieides in field bracken has been sludied in some preliminary experiments by means of autoradiography. A detailed account is given of the methods employed. It is shown that when 2,4-D is applied to fronds at different stages of development movement of the tracer into the rhizome is considerably greater from parts of the frond which are still immature. Trasnslocation within the frond is predominantly basipetal at all stages of development; within the rhizome the direction of movement appears to be determined primarily by the nature of the vascular connections with the treated pinna.
In a comparison between the translocation of 2,4-D, 4-CPA and dalapon no difference was apparent after 24 hours, but when the treatment period was extended to 96 hours there was evidence that 4-CPA bad been translocated in a considerably greater amount than either of the other two herbicides.
Rechrches iréliminaires sur la migration des herbieides marqués am14 C dans la fougrère algle (Pteridium aquilinum) 相似文献
In a comparison between the translocation of 2,4-D, 4-CPA and dalapon no difference was apparent after 24 hours, but when the treatment period was extended to 96 hours there was evidence that 4-CPA bad been translocated in a considerably greater amount than either of the other two herbicides.
Rechrches iréliminaires sur la migration des herbieides marqués am
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烟粉虱感染白僵菌后的组织病理变化 总被引：1，自引：0，他引：1
病症观察表明,烟粉虱感染白僵菌96 h后虫体颜色变为深红色。组织切片观察表明,白僵菌处理后36 h,可在表皮下面观察到芽生孢子。48 h后可在体内观察到明显的菌丝段。60 h可以观察到菌丝入侵到脂肪体中,96 h发现内部组织器官病变,肌肉边界变得模糊不清,体内出现大量菌丝,120 h后菌丝突破体壁向外生长,132 h后形成菌丝层。 相似文献
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In South Bohemia, Czech Republic, 178 shrews, including 98 common shrews, Sorex araneus L., 70 pygmy shrews, Sorex minutus L., and 10 lesser white-toothed shrews, Crocidura suaveolens (Pallas), were examined for Soricimyxum fegati Prunescu, Prunescu, Pucek et Lom, 2007 infections, using squash preparations of unfixed tissues, histological sections and molecular methods. The infection was found in 51 (52%) S. araneus, 14 (20%) S. minutus and 1 (10%) C. suaveolens. The records of the latter two species extend host range of S. fegati. Lesions associated with S. fegati infections in the liver, the organ of specific localisation of the parasite, were found to be induced by proliferative stages migrating toward lumina of bile ducts. In other organs of these three host species, xenoma-like formations (XLFs) were found that severely injured blood vessels. XLFs contained presporogonic stages of S. fegati, whose species identity was evidenced using molecular methods. 相似文献
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为了测定菵草抗性生物型SD-04-SS和敏感生物型SD-12对精唑禾草灵代谢速度的差异,建立了精唑禾草灵及其主要代谢产物精唑禾草酸、6-氯苯并唑酮的高效液相色谱(HPLC)分析方法.结果表明,在0.123~30.000 μg/mL范围内、0.977~1 000.000 μg/mL范围内、0.469~30.000 μg/mL范围内6-氯苯并唑酮、精唑禾草酸、精唑禾草灵浓度与响应值线性关系良好,相关系数(r)分别为0.991 2、0.972 2、0.996 3.应用上述方法分析发现,精唑禾草灵处理后2 h在菵草体内即可检测到精唑禾草酸和6-氯苯并唑酮,药后2~96 h抗性生物型SD-04-SS体内精唑禾草灵的含量始终略高于敏感生物型SD-12,药后24~72 h抗性生物型SD-04-SS体内精唑禾草酸的含量显著低于敏感生物型SD-12,说明抗性生物型降解精唑禾草酸的速度比敏感生物型更快. 相似文献
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Vieira P Banora MY Castagnone-Sereno P Rosso MN Engler G de Almeida Engler J 《Phytopathology》2012,102(10):990-996
Plant-parasitic nematodes possess a large number of proteins that are secreted in planta, allowing them to be successful parasites of plants. The majority of these proteins are synthesized mainly in the nematode subventral and dorsal glands as well as in other organs. To improve the immunovisualization of these proteins, we adapted a methacrylate embedding method for the localization of proteins inside nematode tissues, and extracellularly when secreted in planta or within plant cells. An important advantage is that the method is applicable for all nematode stages: preparasitic as well as parasitic stages, including large mature females. Herein, the method has been successfully applied for the localization of four nematode secreted proteins, such as Mi-MAP-1, Mi-CBM2-bearing proteins, Mi-PEL3, and Mi-6D4. In addition, we could also localize 14-3-3 proteins, as well as two cytoskeletal proteins, by double-immunolabeling on preparasitic juveniles. Superior preservation of nematode and plant morphology, allowed more accurate protein localization as compared with other methods. Besides excellent epitope preservation, dissolution of methacrylate from tissue sections unmasks target proteins and thereby drastically increases antibody access. 相似文献
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Two-week-old seedlings of two rice varieties, resistant CH13 and susceptible Benibhog, were inoculated with a conidial suspension ofHelminthosporium oryzae. The resistant host exhibited greater peroxidase activity than the susceptible one when infected with the pathogen. Enzyme activities were measured 0, 24, 48, 72, 96 and 120 h after infection. Peroxidase activity in diseased leaves bearing young lesions,i.e., 24 h after inoculation, was not appreciably different from that in non-infected leaves. At the intermediate and mature stages of lesion development,ri.e., 72 and 120 h after inoculation, a marked increase in peroxidase activity was observed. The pattern of increased enzyme activity was similar in both varieties but the whole event proceeded faster in the resistant variety. No marked change in peroxidase activity in healthy leaves of both the varieties was noticed with increase of seedling age. 相似文献
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Loma salmonae is a common gill parasite of salmonids, and essentially all species in the genus Oncorhynchus are susceptible. Infections occur in both fresh and salt water. Loma salmonae is directly transmissible by ingestion of spores or infected tissue. The parasite infects the wall of blood vessels of various organs, but the gill is the primary site of infection. Initial infection occurs in the intestine, and xenomas are easily detected in the gills by standard histology at 4-6 wk post-exposure. A few presporogonic stages of the parasite are found in the heart endothelium prior to xenoma formation in the gills. Ultrastructure studies of early infections demonstrated that wandering blood cells transport the meronts to the gills, and that merogony occurs in pillar cells and other cells underlying the gill endothelium. Xenomas develop in these cells, resulting in hypertrophied host cells filled with spores. Xenomas ultimately rupture, and are associated with severe inflammation in which free spores are found in macrophages. The parasites are most pathogenic during this phase of the infection, resulting in severe vasculitis and clinical disease. Both rainbow trout (Oncorhynchus mykiss) and Chinook salmon (Oncorhynchus ishawytscha) recover from infections, but free spores persist in kidney and spleen phagocytes for many months after xenomas are absent in Chinook salmon. Fish that have recovered from the infection show strong immunity against the parasite, lasting up to 1 year. Fish are susceptible to infection by other routes of exposure by spores; co-habitation, anal gavage, and intramuscular, intraperitoneal and intravascular injection. Autoinfection probably occurs following release of spores in blood vessels after xenomas rupture. The optimal temperature for L. salmonae infections is 15-17 degrees C, with a permissive range of 11-20 degrees C. 相似文献
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Two experimental trials were performed to elucidate the role of rodents in the life cycle of Hepatozoon species using snakes as intermediate hosts. In one trial, two ball pythons, Python regius Shaw, 1802 were force fed livers of laboratory mice previously inoculated with sporocysts of Hepatozoon ayorgbor Sloboda, Kamler, Bulantová, Votypka et Modry, 2007. Transmission was successful in these experimentally infected snakes as evidenced by the appearance of intraerythrocytic gamonts, which persisted until the end of trial, 12 months after inoculation. Developmental stages of haemogregarines were not observed in histological sections from mice. In another experimental trial, a presence of haemogregarine DNA in mice inoculated with H. ayorgbor was demonstrated by PCR in the liver, lungs and spleen. 相似文献
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Pfender WF 《Phytopathology》2004,94(3):308-316
ABSTRACT Perennial ryegrass (Lolium perenne) was inoculated with urediniospores of Puccinia graminis subsp. graminicola at four stages of reproductive tiller development. All developmental stages, from expansion of the penultimate leaf through anthesis, were equally susceptible to infection measured as number of pustules per total inoculated plant area. However, within each stage from boot through anthesis, there was a negative correlation of susceptibility with age of host tissue, the highest disease severities occurring on expanding or newly expanded leaves or inflorescences. Within-plant spread of the disease from primary lesions on the flag leaf sheath to the elongating stem of the inflorescence was observed and verified. A single primary infection on the leaf sheath can produce an elongated strip of contiguous secondary infections on the inflorescence head and stem, which is a characteristic sign of stem rust. Position and timing of eruption of the secondary pustules on the stem can be explained by assuming that infections occur on the stem slightly distal to the overlying sheath lesion and erupt one latent period later, by which time tiller elongation has moved the stem infection site upward. Repeated infections occur as the stem elongates, producing contiguous lesions. Expansion rate and final lesion area on the stem were correlated with elongation rate of the inflorescence. Microscopic observation of plant tissue sections revealed that the fungus sporulates on the inner surface of the sheath, and germinating urediniospores are attached to the stem surface under the covering sheath starting 1 to 2 cm distal to the location of the sheath infection site. 相似文献
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Escherichia coli endotoxin instilled intranasally into mice and rats caused a severe pulmonary oedema associated with progressive increases in lung weights of up to 30% within 2 days. When mice were injected with DDT (20 mg/kg) 20 and 2 hr prior to the administration of endotoxin the animals were found to be tolerant to the endotoxin. The inflammatory oedema induced by endotoxin is caused by release of lung histamine, and as DDT injections also lowered histamine content in the lungs, the protective effect of DDT against the oedema induced by endotoxin appears to be due to its prior depletion of the lung histamine stores. An opposite effect, increased and accelerated inflammation, was observed by chronic exposure of rats to dietary DDT (150 ppm) fed for 36 days. The long-term feeding of DDT is known to cause adaptations in many physiological systems. One of these may be increased histamine synthesis and subsequently increased severity of histamine mediated reactions. 相似文献
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为了明确水稻田除草剂三唑磺草酮(QYR301)的最佳施药条件,以稗草Echinochloa crus-galli和水稻Oryza sativa作为测试靶标,采用温室盆栽法研究了其施药适期、耐雨水冲刷性、温度和光照强度对其除草活性的影响。结果显示:三唑磺草酮对不同叶龄水稻具有较高的安全性,在有效成分360 g/hm^2的剂量下,对2叶期以后的水稻干重抑制率为0%;其除草活性与稗草的叶龄显著相关,其中2~3叶期的稗草最为敏感,有效成分30 g/hm^2的三唑磺草酮对其干重抑制率为95%~98%;三唑磺草酮具有一定的耐雨水冲刷能力,药后降雨间隔达到8 h以上,其除草活性与药后降雨间隔时间无显著相关性,在有效成分30~120 g/hm^2的剂量下,对稗草的干重抑制率为75%~93%;在20~35℃区间,三唑磺草酮药效稳定,对稗草的GR50值在44.6~51.4 g/hm^2之间;相较于中度光照(45%)和低光照(4%),高光照(100%)条件下三唑磺草酮对稗草的干重抑制率显著增加。分析表明杂草叶龄、降雨、温度和光照会显著影响三唑磺草酮除草活性,为使其发挥最大药效,应选择在水稻2叶期以后至稗草2~4叶期,天气晴朗,气温高于20℃的情况下施药;如药后8 h以内遇降雨天气,则需进行补喷。 相似文献
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The pathogenicity of Ganoderma boninense isolated from oil palm was tested using wood blocks from a rubber tree as the substrate for the inoculum. Seedlings with roots placed in close contact with the inoculum blocks gave 100% infection. There was a progressive desiccation of leaves from the oldest to the youngest. Sporophores emerged as a white mass of mycelial tissue which rapidly became button-like. This was followed by the development of the stipe. Bracket-shaped sporophores formed within 12–16 weeks after inoculation. Longitudinal sections of affected seedlings revealed bole and stem decay. Hyphae were detected in the cortex, endodermis, pericycle and vascular tissues of infected roots. Gummosis and the production of tyloses in xylem vessels were common. 相似文献