A Protozoon in the Central Nervous System of the Lungfish Polypterus enlicheri*

SYNOPSIS. Trophozoites and what appear to be early spore forms of a parasitic protozoan present in the spinal cord of the lungfish Polypterus enlicheri are described. They are probably intra- and extracellular invaders into the anterior horn and are frequently located near capillaries. They provoke a glial response. The organisms have some myxosporidan features (7) and are tentatively classified as cnidosporidans.     

Parasitic infection of the seahorse (Hippocampus erectus)--a case report

This report details the development of a microsporidan infection in a colony of seahorses (Hippocampus erectus) caused by Glugea heraldi. Of 76 animals imported from Florida Bay (USA), two survived. A myxosporidan (Sphaeromyxa sp.) and an unidentified nematode infection were also diagnosed in the same colony, but these infections were not considered important, causative factors in the mortalities.     

Occurrence of the Myxosporidan Parasite Myxidium minteri in Salmonid Fish1

SYNOPSIS. The myxosporidan Myxidium minteri was found in 3 recognized hosts, chinook and coho salmon and rainbow trout and 2 new hosts, cutthroat trout and mountain whitefish. Spores in all species examined were found primarily in the gall bladder. Fish infected with this parasite were obtained from both Oregon coastal rivers and Columbia River basin locations. In general the prevalence of infection was higher in the fish in coastal rivers.     

Myxosporida (Protozoa): The determination and maintenance of spore size and shape

Data are presented which suggest that the size of fish myxosporidan spores is primarily determined by the parasite's development in the tissues or organ's cavities and the spore's shape is determined by the presence of physiologically and behaviorally suitable fish.     

Fish Infected with Sphaerospora spp. Thélohan (Myxosporea) from Waters Enzootic for Proliferative Kidney Disease of Salmonids1

ABSTRACT. Sphaerospores were found among three species of fish examined from waters known to be enzootic for proliferative kidney disease (PKD) of salmonids. They were detected in the renal tubules of both hatchery-reared rainbow trout (Salmo gairdneri) exposed to the infectious stage of PKD and in chubs (Gila bicolor) in the headwaters of a hatchery where PKD is enzootic. Sticklebacks (Gasterosteus aculeatus) collected near net pens where Pacific salmon had experienced a PKD epizootic were also found to harbor sphaerospores in the lumen of the kidney tubules. The latter two host species contained developmental stages of a myxosporidan in the blood and in the lumen of the kidney tubules which are similar to those of PKX, the causative agent of PKD in salmonid fish. The sphaerospores observed in the rainbow trout are the first to be observed in this species. The similarity to previously observed developmental stages, rarity, and presence of these sphaerospores in salmonid fish from a hatchery where PKD is enzootic suggest that they are the most mature stage of the PKX myxosporidan yet observed.     

Fish infected with Sphaerospora spp. Thélohan (Myxosporea) from waters enzootic for proliferative kidney disease of salmonids

Sphaerospores were found among three species of fish examined from waters known to be enzootic for proliferative kidney disease (PKD) of salmonids. They were detected in the renal tubules of both hatchery-reared rainbow trout (Salmo gairdneri) exposed to the infectious stage of PKD and in chubs (Gila bicolor) in the headwaters of a hatchery where PKD is enzootic. Sticklebacks (Gasterosteus aculeatus) collected near net pens where Pacific salmon had experienced a PKD epizootic were also found to harbor sphaerospores in the lumen of the kidney tubules. The latter two host species contained developmental stages of a myxosporidan in the blood and in the lumen of the kidney tubules which are similar to those of PKX, the causative agent of PKD in salmonid fish. The sphaerospores observed in the rainbow trout are the first to be observed in this species. The similarity to previously observed developmental stages, rarity, and presence of these sphaerospores in salmonid fish from a hatchery where PKD is enzootic suggest that they are the most mature stage of the PKX myxosporidan yet observed.     

Effects of fixation, dehydration and staining on dimensions of myxosporidan

The effects of fixation, dehydration and staining on the morphological dimensions of myxo- and microsporidan spores were tested. Seven fixatives, two dehydrants and five stains were tested. Ten % formalin produced the least shrinkage and provided the best cytological detail of fixed material in both types of spores. All fixatives caused shrinkage of myxosporidan spore length and polar capsule length. Spore capsule width and polar capsule width were unaffected by 10% formalin. Ethyl alcohol caused no significant change in spore width. Microsporidan spore length shrunk with all fixatives, but spore width was generally unaffected. Dehydration, with either isopropyl alcohol or acetone, produced additional, significant shrinkage. The influence of stains on spore size was negligible. Heidenhains iron hematoxylin followed by eosin, and Mallory's analine-blue collagen stain, effectively stained myxo- and microsporidan spores.     

The Nature of the Iodinophilous Vacuole of Myxosporidan Spores, and a Proposal to Synonymize the Genus Myxosoma Thélohan, 1892 with the Genus Myxobolus Bütschli, 1882

SYNOPSIS. The myxosporidan genera Myxobolus and Myxosoma differ only by the presence or absence of a so-called iodinophilous vacuole in their spores which has in the past been shown to contain glycogen. In the present study, spores of Myxobolus pseudodispar, M. cyprini, M. muelleri, Myxosoma heterospora and Agarella gracilis were tested for glycogen using Best's carmine, iodine, and the Bauer-Feulgen technic. These tests showed that (a) Glycogen was present in variable amounts in spores of each species. In some spores this took the form of a vacuole, while in others the distribution was diffuse or particulate; (b) In no species of Myxobolus did the majority of spores contain a vacuole; (c) In Myxosoma heterospora vacuoles were present in a small proportion of spores. It is concluded that the iodinophilous vacuole cannot be used as a taxonomic criterion in the Myxosporida, and therefore that the genus Myxosoma should be synonymised with the genus Myxobolus .     

Five New Species of Henneguya (Protozoa: Myxosporida) from Ictalurid Fishes*

SYNOPSIS. Four new species of Henneguya (myxosporidan) are described from Ictalurus punctatus Rafinesque (channel catfish). They are as follows: Henneguya postexilis sp. n. and Henneguya longicauda sp. n. from the gills; Henneguya adiposa sp. n. from the adipose fin; and Henneguya diversis sp. n. from the liver, kidney, connective tissue of muscles and fins, and tumor-like external growths. Henneguya pellis sp. n. is described from the dermis of Ictalurus furcatus (LeSueur) (blue catfish). The development stages of all described species are discussed. Henneguya exilis Kudo was found on the gills of one I. punctatus; notes on its spore characteristics are presented.     

Some Myxosporida from Marine Fishes in South Florida1

SYNOPSIS. Myxosoma cephalis n. sp. is described from the brain meninges, gills, jaw bone, crop tissue and buccal cavity of Mugil cephalus Linnaeus (striped mullet) of south Florida. The fresh spore is subspherical in front view, lenticular in side view and averages 14.1 × 11.0 × 9.0 μ (length, width, thickness). The sutural ridge is broad, the sutural line is faintly visible and the polar filaments are coiled 4–5 times. This parasite is apparently associated with an epizootic in mullet. Three species of beloniform fishes from south Florida waters were examined for myxosporidan parasites. New host records and extensions of ranges are provided for Myxidium sphaericum Thélohan in Strongylura timucu (Walbaum) (timucu), and Ceratomyxa aggregata Davis in Hyporhamphus unifasciatus (Ranzani) (halfbeak). A single spore of the genus Myxidium was found in the gall bladder of Hemiramphus brasiliensis Linnaeus (ballyhoo).     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

医疗机构合理用药评价模型的构建研究

目的 针对医疗机构的合理用药水平进行评价研究。方法 根据医疗机构合理用药的具体要求,构建医疗机构合理用药评价指标体系,采用基于模糊群决策的方法和多指标评价分析法构建医疗机构合理用药评价模型。结果 构建了基于模糊群决策的医疗机构合理用药评价模型,并通过实例分析证明了评价模型的可行性。结论 建立的基于模糊群决策的医疗机构合理用药评价模型能够对医疗机构的合理用药水平进行科学评价,为提高医疗机构合理用药水平奠定基础。     

青蒿素生物合成机理研究现状

本文总结了目前有关青蒿素生物合成机理方面的研究,主要包括青蒿素生物合成中生理因子的影响,青蒿素生物合成中间体及前体,青蒿素生物合成细胞定位等。指出了存在的一些问题及今后的研究发展前景。     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Estimation of the Timing of Perinatal Transmission of HIV

Knowledge of the timing of perinatal transmission of HIV would be valuable for the determination and evaluation of preventive treatments and would shed light on the mechanism of transmission. Estimation of the distribution of the time of perinatal transmission is difficult, however, because tests of infection status can only be undertaken after birth. DNA and RNA polymerase chain reaction (PCR) assays and HIV culture have been the most commonly used diagnostic tests for perinatal HIV infection. Such tests have high sensitivity and specificity, except when they are given shortly after infection. In this paper we use the time-dependent sensitivity of these diagnostic tests to make nonparametric and semiparametric inferences about the distribution of the time of perinatal HIV transmission as well as the cumulative probability of perinatal transmission. The methods are illustrated with data from a clinical trial conducted by the AIDS Clinical Trials group.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.